Download - Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

Transcript
Page 1: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GravityVolume IV, 2013 SSNC

Physics SocietySwami Shraddhanand College

University of Delhi, Alipur, Delhi-110036

Page 2: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

2GRAVITY 2013-14

Inaugural of ESST-2012 Renewable Energy Exhibition-

Lecture on God Particle Lecture on God Particle

Discussion Session of EESC- Valedictory Session of ESST-

Physics Activities 2013-14Physics Activities 2013-14Physics Activities 2013-14Physics Activities 2013-14Physics Activities 2013-14

Shri Krishna Sahitya Sadan

Page 3: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 3

MessageFrom the Desk of the Principal

I am glad to know that the Department of Physics of the college is planningto bring out the fifth issue of the magazine “Gravity” which will enable thestudents and teachers to express their views on the most recent happenings infield of Physics. As has been with the previous issue, the magazine shall includeother departmental activities and variety of information to stimulate academicdialogue.

I wish all the best for the success of the magazine and future activities ofthe department.

Dr. S.K. Kundra Dr. S.K. Kundra Dr. S.K. Kundra Dr. S.K. Kundra Dr. S.K. Kundra Principal,SSNC

Lokeh JºkuUn egkfo|ky;(fnYyh fo'ofo|ky;)] vyhiqj] fnYyh&110036

Swami Shraddhanand College(University of Delhi), Alipur, Delhi-110036

Page 4: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

4GRAVITY 2013-14

MessageMessageMessageMessageMessage From teacher In-charge of the Physics From teacher In-charge of the Physics From teacher In-charge of the Physics From teacher In-charge of the Physics From teacher In-charge of the Physics

DepartmentDepartmentDepartmentDepartmentDepartmentSwami Shraddhanand CollegeSwami Shraddhanand CollegeSwami Shraddhanand CollegeSwami Shraddhanand CollegeSwami Shraddhanand College

It is the matter of great happiness and pride to announce the fifth issueof departmental magazine “GRAVITY”. The “Gravity” will enable thestudents and teachers to express their views on the most recent happenings infield of Physics.

As precurred with the previous issue the magazine shall include otherdepartmental activities and variety of information to stimulate academicdialogue.

Wish the magazine a great success.

Dr. Vinod PrasadDr. Vinod PrasadDr. Vinod PrasadDr. Vinod PrasadDr. Vinod Prasad

Teacher Incharge,

Department of Physics

Lokeh JºkuUn egkfo|ky;(fnYyh fo'ofo|ky;)] vyhiqj] fnYyh&110036

Swami Shraddhanand College(University of Delhi), Alipur, Delhi-110036

Page 5: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 5

Preface & Editorial

The Physics department of SSN College came out with fresh edition of itsannual publication “GRAVITY”.“GRAVITY”.“GRAVITY”.“GRAVITY”.“GRAVITY”. The main motto behind it was to bring thewandering minds into the wondering minds.

This edition of magazine contains a wide range of topics which lie in thearena of your interest and enhance your curiosity in knowing the nature ofscience. As always, we reached out to a distinguished panel of contributors andas usual we have run up a huge debt of gratitude.

This issue cleaves many hidden facts and figures also that could be accessibleto all. Knowledge is immeasurably vast but it should not dampen one frompursuing the quest for knowledge. Its single spark leads us to new horizon andspirituality. This ordinary magazine is an extraordinary step towards perennialspring of knowledge which can alone quench the thirst of soul. I hope morestudents will join the caravan on this path of knowledge in years to come andreaders will boost their morale and confidence in their own ways.

All of this would have been impossible without the constant efforts of ourteam, who expediently managed the subject of content and design to bringforth this issue in time.

I hope you enjoy this journey which aims to provide enough matter toarouse your interest but not enough to keep you from wanting more.

“Gravity is a translation of wonderful ideas of physics…”

EDITORIAL BOARD

Dr. Mukesh Rana Dr. Mukesh Rana Dr. Mukesh Rana Dr. Mukesh Rana Dr. Mukesh Rana . Bhartendu, Physics(H) 3rd year

Prashant, physics(H) 1st year

Lokeh JºkuUn egkfo|ky;(fnYyh fo'ofo|ky;)] vyhiqj] fnYyh&110036

Swami Shraddhanand College(University of Delhi), Alipur, Delhi-110036

Page 6: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

6GRAVITY 2013-14

INDEX

Teacher CornerTeacher CornerTeacher CornerTeacher CornerTeacher Corner

1. Nature, Symmetry and Conservation Laws — Dr. Mukesh Kumar

2. Mysteries of Outer Space — Dr. Ruby Gupta

3. 10 Things that Happe to an exposed — Dr. Monica Gambhir

Humans in Space.

4. Overview of Rotational Dynamics, — Urvashi Arya

Orientation and Alignment of molecules

Almuni SectionAlmuni SectionAlmuni SectionAlmuni SectionAlmuni Section

5. nm-Scaled motion of charge carriers ————— Vedant Dhaka

6. Science & Spirituality — Swetank Bhartiprobed by microwaves

Student SectionStudent SectionStudent SectionStudent SectionStudent Section

7. Gravity light — Bhartendu Papnai

8. Light came second? — DigvijayShighTomar

9. Pros and cons of nuclear power. — SauravSarkar

10. Oh Physics! — Ashish Kumar

11. Einstein life and his achievements. — AnjuDeshwal

12. Newton’s Biography — Komal Chauhan

13. Power saver: Can it really help to reduce — VikasBeliwalour electricity bill.

14. nm-Scaled motion of charge carriers — Vedant Dhakaprobed by microwaves.

15. The Importance of Physics to — Kiranman and Society

16. Time travel — Prashant Joshi

17. Terraforming. — Prashant Tyagi

18. God Particle — Sanjeet Kumar

19. Vehicle’s Electric Charging System — Sagar Dahiya

Page 7: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 7

The nature is essential to beconsidered in the way of promotinghuman economic growth. Nearlyeveryone admits the importance ofscience in understanding naturalphenomena . We cannot alter the waynature works, but we can put its lawsto our use if we know what they are.The supremacy of nature, to definethe natural phenomena is alsodescribed in Hindu philosophy viz.

Bhµumiråpo analo vayu ̈kham mano Buddhireva ca

Aha≈kårak it∂yam me bhinna prakætirastadhå

(The laws of Natural sciences do not go beyond thedomain of these eight constituents of Nature - Earth,

Water, Fire, Air, Ether, Mind, Intellect and Ego)

[Ref. Srimad Bhagwad - Gita : chapter7, verse 4]

Physical world appears to operateaccording to certain fixed principlesas described. They may be written interms of words, equations or inequa-lities, but they are all summaries ofpatterns which have been discoveredin nature.

It was the great achievement ofSir Isaac Newton to find a single setof physical laws which would explainmost of the natural phenomena. AfterNewton one expected much morefrom a physical theory than that itshould fit a limited set of data. It is

the science of Mechanics which seeksto define the quantities that are vitalto the description of motion anddiscover the laws that govern themotion to establish phenomena.

The first complete formulation ofthe physical theory of dynamics wasbrought by Newton (1642 - 1729)in his famous book, { PhilosophiaerNatural’s Principia Mathematica},probably, the most important singlework ever published in the physicalscience. After Newton, a very widerange of physical theories weredeveloped and elaborated by G.W.Leibnitz (1646-1716),L.Euler (1707-1783), J.L.Lagrange (1736-1813),S.D.Poisson (1781-1840),C.G.J.Jacobi (1804-1851),W.R. Hamilton(1805-1865), M.Lie (1842-1899),A.E.Noether (1882-1935) and manyothers. Even now the Newtonianmechanics forms the basis for thedescription of motion of macroscopicparticles like planets.

Let us study few Natural factLet us study few Natural factLet us study few Natural factLet us study few Natural factLet us study few Natural fact

• An isolated system of particlescan be set into motion in manydifferent ways, no matter how westart the system moving, its

Dr. Mukesh KumarDr. Mukesh KumarDr. Mukesh KumarDr. Mukesh KumarDr. Mukesh KumarAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNC

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Nature, Symmetry and Conservation Laws

Page 8: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

8GRAVITY 2013-14

energy that remain the same.That energy might characterizethe system itself, rather thanparticular state of motion wechoose. The particular from ofthe energy function containsdetailed information about howone configuration of the systemdeveloped into another such thatthe energy retains the initialvalue.

• Most of the physical pheno-mena around us are observed tobe regular. For example , the sunrises in east and sets in the west,the earth spins about its axis andrevolves around the sun etc.

• The laws of physics are not foundto change day by day. Forexample, energy used incompressing a spring today wouldbe exactly the same as that isrecovered by releasing the springtomorrow.

• We can express the laws ofnature in the form that look thesame to all inertial obser-vers, nomatter where they are or how theyare moving .

The physical laws that describe theabove given phenomena, show thatsuch laws exhibit invariance prin-ciples. The invariance is not just aconvention about how laws arewritten down, but a very powerfulrestriction on which laws are possible.The physicists have a special term forgeometric idea of invariance, called

symmetry. A similar idea of symmetryis also well known in ancient time,Viz.,

“Vyasti in Samasti” or “Samasti in Vyasti”

(All in one) (One in All)[Reference : Srimad Bhagwad - Gita :

chapter 3, verse 11]

The significance of symmetry wasrealized very early in the classic workof H. Weyl , in 1928 as :“Symmetry is one idea by which man throughthe ages has tried to comprehend and create

order ,beauty and perfection.”

The concept of symmetry arisesfrom Euclidean abstractions likeperfect cube, perfect spheres etc. Theidea of symmetry is that of lack ofperceptible difference once antransformation has been performed.

A transformation is a rule of somekind whereby the appropriate imagecan be derived for every state ofsystem. A transformation acts on asystem no matter what state it is in.Analytic analogue of symmetry iscalled invariance. A function isinvariant when it does not change

Page 9: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 9

under a transformation; samegeometrical appearance of an objectfrom two or more differentperspectives is called symmetry.Conservation laws refer to a physicalquantity that remains constantthroughout the multitude of processeswhich occur in nature. Indeed,conservation laws of a system is oftenthe first step toward its solutions, moreconservation laws means moreprecisely the solution. An illustrationof the deep connection amongsymmetry, invariance and conser-vation laws is:

Symmetry Operation Conservation Laws

Translation in Space Linear Momentum

Rotation in Space Angular Momentum

Translation in Time EnergyReflection about a plane Parity

or point in Space

Lorentz Transformation Energy-Momentum Relation

Gauge Transformation of Electric Charge

electromagnetic Potentials

Permutations of identical Bose-Einstein or Fermi-

Particle Dirac Statistics

For example, a square is invariantunder rotation by 90 degree or 180

degree or 270 degree about an axisthrough its center and perpendicularto its plane, since its shape is such thatthe result of this rotation is indistin-guishable from the initial state forevery state. All the invariant states aresymmetric state. For example, If thetransformation along a particularCartesian axis provide the invarianceof Euclidean space, it has the symmetryalong that Cartesian axis , and thereexists a conserved quantity calledlinear momentum along that axis.

Symmetry which implies conser-vation laws, is a useful physicalconcept. It is the conservation lawsthat are responsible for the descriptionof the natural behavior. This is whythe conservation laws are so impor-tant.

Hence symmetry is a geometricidea, transformation is a geometricoperation, invariance is its algebraicor analytic idea and conservation lawis the useful physical output.

Page 10: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

10GRAVITY 2013-14

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Since the beginning of life, man has

looked to the stars with a sense of

wonder. Between then and now,

many advances have been made in the

fields of astronomy, mathematics, and

physics in an attempt to explain the

things we see above, yet the more we

believe we understand, the less we

really seem to know. In something as

big as the universe, there are bound

to be unexplainable phenomena, and

things we truly can’t grasp. The

universe shows us how small we really

are, and in a place so big, is it really

plausible to believe that we are alone?

And is there any reason someone

might not want us to know? This is a

list of what I believe to be some of the

best mysteries and conspiracy theories

of outer space.

1. Dark Energy1. Dark Energy1. Dark Energy1. Dark Energy1. Dark Energy

Dark energy is the greatest mystery in

the universe today, because of the fact

that it is believed to be all around us,

and it explains why there seems to be

anomalies within the law of gravity.

By the law of gravity, large objects, like

galaxy clusters, should attract each

other, and their gravita-tional pull

should pull in other objects. This

however, is not the case, and the fact

is most galaxy clusters are moving

farther apart. This is due to the fact

that the universe is expanding at an

incredible rate. To answer the

question of why this is, scientists

developed the theory of Dark Energy,

which has the opposite effect as

gravity, pushing things apart.

Mathematical calculations have shown

that if it exists, it makes up 74% of

our universe, outweighing gravity, and

this is why the universe is stretching

out. However we still have no

conclusive proof, so it remains a

mystery to us.

2. Ruins on Moon2. Ruins on Moon2. Ruins on Moon2. Ruins on Moon2. Ruins on Moon

In this list we have discussed the

possibility of life on distant planets,

and in near planets. But could it

possibly at one time have been as close

as the moon? This conspiracy theory

states that there are indeed ancient

ruins and buildings on the moon, but

the government has been censoring

them from the public. This theory had

Mysteries of Outer Space

Dr. Ruby GuptaDr. Ruby GuptaDr. Ruby GuptaDr. Ruby GuptaDr. Ruby GuptaAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNC

Page 11: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 11

no backing until two recent

breakthroughs. A man who claims to

have worked for the government

censoring moon photos came forward

with several, explaining how the

censorship was done and that indeed

there were structures on the moon.

More recently, scientist announced

they believe they have discovered

water, possibly in ice or liquid form,

under the surface of the moon. For

conspiracy theorists, this was all the

proof they needed, while critics

dismiss it as “ridiculous speculation”.

3. “White” Holes3. “White” Holes3. “White” Holes3. “White” Holes3. “White” Holes

One of Albert Einstein’s greatest

accomplishments was the proving,

though mathematics, the existence of

black holes. From the advances in

technology, we now have been able

to find several black holes, and believe

one to be at the center of our very own

Milky Way galaxy. What is astonis-

hing, however, is what Einstein also

proved through his equations; white

holes also exist. The exact opposite of

black holes, white holes are believed

to “spit out” an incredible amount of

matter from seemingly nothing. Such

an object should be easy to find, yet

none have been. If one was found, it

may help us explain other unknown

mysteries, such as where the material

that made the galaxies came from.

4. UFO sight ings by NASA4. UFO sight ings by NASA4. UFO sight ings by NASA4. UFO sight ings by NASA4. UFO sight ings by NASA

AstronautsAstronautsAstronautsAstronautsAstronauts

NASA Astronauts are some of the

most highly trained and specialized

people in the world. Often they are

expert scientists that can explain

almost anything. So when they see

something they can’t explain, you can

bet it is going to raise eyebrows. One

of the most famous incidents occurred

on a live broadcast on NBC in 1963.

Major Gordon Cooper was at the end

of his 22 orbit solo journey around

the earth when he said that out of one

of his windows he could see a glowing

green object fast approaching. The

object then made a sharp turn and

shot away. He was sure he was not

seeing things, as the radar in his

spacecraft picked up the object as well.

Upon his return to earth interviewers

wanted to ask him about the object,

however NASA officials would not

allow it.

5. Mars/ Earth Connection5. Mars/ Earth Connection5. Mars/ Earth Connection5. Mars/ Earth Connection5. Mars/ Earth Connection

When talking about life on other

planets, some say we need go no

further than our own solar system.

Mars has always been thought to

harbor life by many conspiracy

theorists, saying that NASA is

covering it up. Many photos have also

called into question civilization on

Mars, such as the face on Mars,

Pyramids on Mars, and photo of what

appears to be an ape like figure sitting

Page 12: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

12GRAVITY 2013-14

on a rock on Mars. While scientists

have come out to debunk these

photos, they have also admitted that

they believe liquid oceans once

covered the surface of Mars before its

magnetic field disappeared. Is it

possible that life did indeed once exist?

The current mission to Mars hopes to

answer this question.

6. 6. 6. 6. 6. Dark MatterDark MatterDark MatterDark MatterDark Matter

Albert Einstein’s equation E = MC2 is

perhaps the best known equation of

the century. However when applied

to space, an anomaly occurs. When

we use it to determine how much

matter the universe should have, we

realize that we have only found four

percent of the matter in the universe!

Where is the rest of it? Many believe

it is in the form of dark matter. Where

is this dark matter? It’s every-

where, wherever there is no visible

matter. Scientists have yet to show any

conclusive proof that dark matter does

in fact exist. The fact that you can’t

see it, touch it, and light and radio

waves pass right through it undeterred

makes it extremely hard to detect.

7. Are there Other Universes?7. Are there Other Universes?7. Are there Other Universes?7. Are there Other Universes?7. Are there Other Universes?

This is one of the more controversial

arguments out there. The theory is

that there are an infinite number of

universes, each of which is governed

by its own set of laws and physics.

Many scientists dismiss this argument

as nothing more than speculation, as

there is no evidence or mathematical

law that allows for the existence of

other universes. However, believers in

this theory have argued that there are

none that disprove it either. This is

one mystery which can only be solved

if we were able to travel there;

however, with the expansion of the

universe, it is unlikely humanity will

ever find the answer.

8. Other Earths8. Other Earths8. Other Earths8. Other Earths8. Other Earths

Our star, the sun, is just one of trillions

in the universe. When you look at the

fact that our star has eight planets, and

do the math, it tells you that it is

possible for there to be eight times as

many planets in the universe than

stars; an astounding figure. Is it not

possible that just one of those planets

might have life on it? It is a fact that,

since the year 2000, hundreds of extra

solar planets have been discovered

orbiting distant stars. Some of these

have found to be earth- like, such as

the planet Gliese 581d, a planet

believed to have liquid water on its

surface. Could it possibly contain life?

Hopefully with advances in

technology in the next decade, we will

soon know the answer. Till then, it

remains one of space’s greatest

mysteries.

9. Where did galaxies come from?9. Where did galaxies come from?9. Where did galaxies come from?9. Where did galaxies come from?9. Where did galaxies come from?

Page 13: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 13

123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789011234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890112345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901

Science has only recently been able to

explain where the stars and planets

came from. Now, scientists have

turned their attention to a much

bigger mystery, where did galaxies

come from? What is known is that

galaxies are not scattered randomly

throughout space, rather they are

found in clusters, known as “super

clusters”. Scientists have two main

theories to attempt to explain galaxy

formation. First, the gas left over from

the big bang clustered together to

form galaxies, in which stars and

planets were born. Second is that gas

from the big bang created stars and

planets all over the universe, and they

migrated through gravity into galaxies.

Neither theory has been universally

accepted yet.

10. Simulacrum in Eagle Nebula10. Simulacrum in Eagle Nebula10. Simulacrum in Eagle Nebula10. Simulacrum in Eagle Nebula10. Simulacrum in Eagle Nebula

One of the strangest photos that have

ever been taken of space is that of the

Eagle Nebula. The photo itself is

supposed to show the birth of a star

from the gaseous clouds. However,

when the photo was shown on CNN,

hundreds of calls came in from people

reporting they could see a face in the

cloud. When the color of the photo

was adjusted, a large human form

seemed to appear within the cloud.

Scientists have not been able to

explain this phenomenon.

Wilhelm Conrad Rontgen (1845 - 1923)

It was on 8th November 1895, that Rontgen detected aIt was on 8th November 1895, that Rontgen detected aIt was on 8th November 1895, that Rontgen detected aIt was on 8th November 1895, that Rontgen detected aIt was on 8th November 1895, that Rontgen detected aspecific wavelength of electromagnetic radiation now knownspecific wavelength of electromagnetic radiation now knownspecific wavelength of electromagnetic radiation now knownspecific wavelength of electromagnetic radiation now knownspecific wavelength of electromagnetic radiation now knownas X-rays. This discovery helped him bag the Nobel prize inas X-rays. This discovery helped him bag the Nobel prize inas X-rays. This discovery helped him bag the Nobel prize inas X-rays. This discovery helped him bag the Nobel prize inas X-rays. This discovery helped him bag the Nobel prize in1901.1901.1901.1901.1901.

Pierre Curie (1859 - 1906) and Marie Curie(1867 - 1934)

A pioneer of radioactivity, piezoelectricity and magnetism,A pioneer of radioactivity, piezoelectricity and magnetism,A pioneer of radioactivity, piezoelectricity and magnetism,A pioneer of radioactivity, piezoelectricity and magnetism,A pioneer of radioactivity, piezoelectricity and magnetism,he shared his Nobel prize, received in 1903, with his wifehe shared his Nobel prize, received in 1903, with his wifehe shared his Nobel prize, received in 1903, with his wifehe shared his Nobel prize, received in 1903, with his wifehe shared his Nobel prize, received in 1903, with his wifeMarie and Prof. Henri Becquerel, for their contribution toMarie and Prof. Henri Becquerel, for their contribution toMarie and Prof. Henri Becquerel, for their contribution toMarie and Prof. Henri Becquerel, for their contribution toMarie and Prof. Henri Becquerel, for their contribution tothe radiation phenomena discovered by Professor Henrithe radiation phenomena discovered by Professor Henrithe radiation phenomena discovered by Professor Henrithe radiation phenomena discovered by Professor Henrithe radiation phenomena discovered by Professor HenriBecquerel. He also put forth the Curie’s law, which showsBecquerel. He also put forth the Curie’s law, which showsBecquerel. He also put forth the Curie’s law, which showsBecquerel. He also put forth the Curie’s law, which showsBecquerel. He also put forth the Curie’s law, which showsthe effect of temperature on paramagnetism. The unit ofthe effect of temperature on paramagnetism. The unit ofthe effect of temperature on paramagnetism. The unit ofthe effect of temperature on paramagnetism. The unit ofthe effect of temperature on paramagnetism. The unit ofradioactivity, ‘Curie’, is also coined after their names.radioactivity, ‘Curie’, is also coined after their names.radioactivity, ‘Curie’, is also coined after their names.radioactivity, ‘Curie’, is also coined after their names.radioactivity, ‘Curie’, is also coined after their names.

Page 14: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

14GRAVITY 2013-14

Physics is a branch of science that is

one of the oldest and also the most

basic type of academic discipline.

Physics is an unconfined subject, and

its boundaries cannot be rigidly

defined. If it were not for the genius

minds who dedicated their lives to the

study of physics and its manifesta-

tions, we wouldn’t have been enjoying

the fruits of their labor like the “oh-

so-essential” computer. The following

list of famous physicists will help you

learn about some of the well-known

physics scientists, who have increased

the acceleration and minimized the

friction in the technological advance-

ment of the world.

Wilhelm Conrad Rontgen (1845 -Wilhelm Conrad Rontgen (1845 -Wilhelm Conrad Rontgen (1845 -Wilhelm Conrad Rontgen (1845 -Wilhelm Conrad Rontgen (1845 -

1923)1923)1923)1923)1923)

It was on 8th November 1895, that

Rontgen detected a specific wave-length of electromagnetic radiationnow known as X-rays. This discovery

helped him bag the Nobel prize in1901.

Pierre Curie (1859 - 1906) andPierre Curie (1859 - 1906) andPierre Curie (1859 - 1906) andPierre Curie (1859 - 1906) andPierre Curie (1859 - 1906) and

Marie Curie (1867 - 1934)Marie Curie (1867 - 1934)Marie Curie (1867 - 1934)Marie Curie (1867 - 1934)Marie Curie (1867 - 1934)

A pioneer of radioactivity, piezoel-ectricity and magnetism, he shared hisNobel prize, received in 1903, withhis wife Marie and Prof. HenriBecquerel, for their contribution tothe radiation phenomena discoveredby Professor Henri Becquerel. He also

List of Famous Physicists

Dr. Monica GambhirDr. Monica GambhirDr. Monica GambhirDr. Monica GambhirDr. Monica Gambhir

Assistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNCAssistant Professor in Physics, SSNC○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Galileo Galilei (1564 - 1642)

An Italian genius, Galileo created the telescope. He discovered

the phases of Venus and, the four satellites of Jupiter: Io, Europa,

Callisto, and Ganymede., He also proved that the ocean tides

were caused due to the gravitational pull of the moon and not

due to the earthís rotation. Compass and thermometer were also

his inventions. He died after he had turned completely blind.

Page 15: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 15

put forth the Curie’s law, which showsthe effect of temperature onparamagnetism. The unit of radio-activity, ‘Curie’, is also coined aftertheir names.

Antoine Henri Becquerel (1852 -Antoine Henri Becquerel (1852 -Antoine Henri Becquerel (1852 -Antoine Henri Becquerel (1852 -Antoine Henri Becquerel (1852 -

1908)1908)1908)1908)1908)

Becquerel shared his Nobel withdoctoral student Marie Curie and herhusband Pierre Curie.

Lord Rayleigh (1842 - 1919)Lord Rayleigh (1842 - 1919)Lord Rayleigh (1842 - 1919)Lord Rayleigh (1842 - 1919)Lord Rayleigh (1842 - 1919)

He earned the Nobel prize for hisdiscovery of argon gas in 1904. Butthere was another phenomenon called‘Rayleigh scattering’ which wasdiscovered by him. ‘Rayleigh waves’,that travel on the solid surfaces, werealso discovered by him.

Johannes Diderik van der WaalsJohannes Diderik van der WaalsJohannes Diderik van der WaalsJohannes Diderik van der WaalsJohannes Diderik van der Waals

(1837 - 1923)(1837 - 1923)(1837 - 1923)(1837 - 1923)(1837 - 1923)

He established the equation of statefor liquids and gases that describes thebehavior of gases and their conden-

sation on the liquid phase. He receivedthe Nobel prize in 1910. Some moreterms like, ‘van der Waals forces’, ‘vander Waals molecules’ and ‘van derWaals radii’ are coined after his nameto honor his accomplishments.

Max Planck (1858 - 1947)Max Planck (1858 - 1947)Max Planck (1858 - 1947)Max Planck (1858 - 1947)Max Planck (1858 - 1947)

Planck established the Quantum

Theory, that earned him the Nobel

prize in 1918. It was one of the

fundamental theories on which

physics rests.

Albert Einstein (1879 - 1955)Albert Einstein (1879 - 1955)Albert Einstein (1879 - 1955)Albert Einstein (1879 - 1955)Albert Einstein (1879 - 1955)

He needs no introduction, Einstein

put forth one of the pillars of modern

physics, ‘General theory of Relativity’.

E=mc2 has been dubbed as the ‘world’s

famous equation’, and it also earned

him a Nobel prize in 1921. In his

lifetime, he published nearly 300

scientific papers.

Niels Bohr (1885 - 1962)Niels Bohr (1885 - 1962)Niels Bohr (1885 - 1962)Niels Bohr (1885 - 1962)Niels Bohr (1885 - 1962)

He put forth the theory of nuclear

James Watt (1736 - 1819)

While repairing a damaged

steam engine, Watt found out

that it was hopelessly inefficient

and tried to improve its design.

While the SI unit of power,

ëWattí, is named after him, the

concept of ëhorsepowerí was

also his brainchild.

Charles-Augustin deCoulomb (1736 - 1806)

Coulombís Law was one of his

greatest contribution to physics.

He invented a device called

ëtorsion balanceí. He also put

forth the fundamental Cou-

lombís Law of electromagne-

tism.

Page 16: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

16GRAVITY 2013-14

reactions and nuclear fission. His

contributions in the field of quantum

mechanics earned this ardent football

player a Nobel prize in 1922.

Sir ChandrasekharaVenkata RamanSir ChandrasekharaVenkata RamanSir ChandrasekharaVenkata RamanSir ChandrasekharaVenkata RamanSir ChandrasekharaVenkata Raman

(1888 - 1970)(1888 - 1970)(1888 - 1970)(1888 - 1970)(1888 - 1970)

His research on scattering of light and

establishing the Raman effect got him

a Nobel prize in 1930. He was an

Indian physicist, who helped India

grow by his influential work. He was

the founder and editor of ‘The Indian

Journal of Physics’.

James Chadwick (1891 - 1974)James Chadwick (1891 - 1974)James Chadwick (1891 - 1974)James Chadwick (1891 - 1974)James Chadwick (1891 - 1974)

Discovery of neutron was his path-

breaking discovery that helped him

bag the coveted Nobel in 1935.

Carl David Anderson (1905 - 1991)Carl David Anderson (1905 - 1991)Carl David Anderson (1905 - 1991)Carl David Anderson (1905 - 1991)Carl David Anderson (1905 - 1991)

While studying the energy distri-

bution of cosmic-rays for his doctoral

thesis, he discovered positron (positive

electron) which bagged him the Nobel

prize in 1936.

Wolfgang Pauli (1900 - 1958)Wolfgang Pauli (1900 - 1958)Wolfgang Pauli (1900 - 1958)Wolfgang Pauli (1900 - 1958)Wolfgang Pauli (1900 - 1958)

Establishing the Pauli principle, which

is also called the exclusion principle,

Pauli received the Nobel prize in

1945.

Dennis Gabor (1900 - 1979)Dennis Gabor (1900 - 1979)Dennis Gabor (1900 - 1979)Dennis Gabor (1900 - 1979)Dennis Gabor (1900 - 1979)

He discovered holography in 1947,

for which he received the Nobel prize

in 1971. However, it became

commercially available only after

1964.

François EnglertFrançois EnglertFrançois EnglertFrançois EnglertFrançois Englert(6 November(6 November(6 November(6 November(6 November

1932)1932)1932)1932)1932)

Awarded the Nobel Prize for physics

in 2013 for the theoretical discovery

of a mechanism that contributes to

our understanding of the origin of

mass of subatomic particles, and

which recently was confirmed through

the discovery of the predicted

fundamental particle, by the ATLAS

and CMS experiments at CERN’s

Large Hadron Collider”

Peter W. Higgs Peter W. Higgs Peter W. Higgs Peter W. Higgs Peter W. Higgs (29 May 1929)(29 May 1929)(29 May 1929)(29 May 1929)(29 May 1929)

Won the Nobel Prize for physics in2013 for predicting the existence ofthe Higgs boson particle that explainshow elementary matter attained themass to form stars and planets.

James Prescott Joule (1818 - 1889)

The first law of thermodynamics was born out of

this relationship. To honor his work, the SI unit of

energy, ëJouleí, is named after him. He also put forth

the Jouleís law.

Page 17: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 17

Overview of Rotational Dynamics,

Orientation and Alignment of molecules

Urvashi AryaUrvashi AryaUrvashi AryaUrvashi AryaUrvashi Arya1,21,21,21,21,2

1. Department of Physics, Swami Shraddhanand College (University Of Delhi), Delhi-110036

2. Department of Physics& Astrophysics University of Delhi, Delhi-110007

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Rotational DynamicsRotational DynamicsRotational DynamicsRotational DynamicsRotational Dynamics

Rotational excitation of molecules isusually studied either under adiabaticor non-adiabatic conditions.Inadiabatic condition, the laser pulseperiod is quite high. According toroughestimate, if Tpulse >5h/B, whereh, is the Planck’s constant and B, isthe rotationalconstant of themolecule, the molecule behaves as ifthe field is static at any instant. Thestates thereby created are thestationary pendular states and in suchcases the rotationalexcitationdynamics follows the laser pulse shape,whereas, in general for smallerpulseduration (i.e. Tpulse< h/B) the timeevolution is said to be non-adiabaticandmolecule is supposed to end up ina rotational wave packet.

Why Molecular Alignment andWhy Molecular Alignment andWhy Molecular Alignment andWhy Molecular Alignment andWhy Molecular Alignment andOrientat ion i s an interest ingOrientat ion i s an interest ingOrientat ion i s an interest ingOrientat ion i s an interest ingOrientat ion i s an interest ingpropertypropertypropertypropertyproperty

F Molecular alignment andorientation allows control overmolecular properties.

AlignmentAlignmentAlignmentAlignmentAlignment

It refers to confinement of molecularaxis with respect toapplied externalfield.

OrientationOrientationOrientationOrientationOrientation

Arrange molecules in a “head versustail” order. The concept of orientationand alignment can be illustrated byconsidering diatomicmolecule AB;here A and B are two different atoms.Because space is isotropic, themole-cular axis are aligned along the spacefixed vertical axis. Alignment meansthatmolecular axis is tied to verticalaxis but the molecule is free to pointeither up anddown. In particular, thismeans that either atom A or B canpoint upwards. In otherwords,

Page 18: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

18GRAVITY 2013-14

alignment behaves as a double headedarrow. Orientation is identified asallmolecules pointing in the samedirection, specifically this means thatwe distinguishbetween whether the Aor the B atom points upward.Whenmolecule is exposed to external,nonionizing electric field, it ispolarized anddipole moment isinduced. As the molecular structureis anisotropic, the moleculemaypolarize more readily in somedirection rather than the other andconsequently theinduced dipolemoment need not be along thedirection of the electric field, butmoregenerally related to the appliedelectric field through the polarizabilitytensor.

Figure 1.Figure 1.Figure 1.Figure 1.Figure 1. Figure: We distinguishbetween orientation andalignment. Fig 1.(a) Showsorientation ‹cosè› of polarmolecules where a directionalaxis, defined by the dipolemo-ment, is aligned with the laserpolarization vector (dashed line).

Fig 1.(b) Alignmentis process inwhich only the molecular axis isconfined, the dipolemoment ofthe polar-molecules can point inany direction and is randomlyoriented. Alignment dynamicsrequantified by the direction-lessparameter ‹cos2è › .

Along with the permanent dipole,the induced dipole interacts with theexternal field and causes the moleculeto rotate into the position thatminimizes the energy of the dipole inelectric field. Now, the electric fieldof the laser is oscillating onfemtosecond time scale, whereas it willtake picoseconds or more for themolecule to change its orientation.Therefore the interaction termsshould average over several laser cycles.This impliesthat the interaction offield with permanent dipole vanishes,as the electric field changessign everyhalf cycle. The polarizability, on theother hand, changes its sign alongthefield, and therefore the interactionterm containing the polarizability doesnot average out.As a result thealignment dynamics of the moleculesin the laser field are determinedbypolarizability.

Methods to orient or align theMethods to orient or align theMethods to orient or align theMethods to orient or align theMethods to orient or align themoleculemoleculemoleculemoleculemolecule

v A weak DC electric field witha pulsed laser field.

v Orienting dipolar molecules

Page 19: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 19

utilizes asymmetric electro-magnetic half-cycle pulses(HCPs).

v Field-free orientation andalignment can be enhanced byusing trains of laser pulses.

v Field-free orientation andalignment can be enhanced bypair of laser pulses.

v Excitation with laser fields offrequencies ù and 2ù .

v Orientation can also beobtained using intense half-cycle and few-cycle laser pulses.

ImportanceImportanceImportanceImportanceImportance

v It can play an important rolein chemical reaction dynamics.

v The steric effects in atom-molecule reactions stronglydepend on the orientation.

v By controlling the mutualorientation of the reagents onecan observe its influence on thereaction probability.

v Orientation of molecule isuseful in laser inducedisomerization, high-orderharmonic generation andcatalysis.

Max Planck (1858 - 1947)

Planck established the Quantum Theory, that earned him the Nobel

prize in 1918. It was one of the fundamental theories on which

physics rests.

Albert Einstein (1879 - 1955)

He needs no introduction, Einstein put forth one of the pillars of

modern physics, ‘General theory of Relativity’. E=mc2 has been

dubbed as the ‘world’s famous equation’, and it also earned him a

Nobel prize in 1921. In his lifetime, he published nearly 300 scientific

papers.

Niels Bohr (1885 - 1962)

He put forth the theory of nuclear reactions and nuclear fission. His

contributions in the field of quantum mechanics earned this ardent

football player a Nobel prize in 1922.

Page 20: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

20GRAVITY 2013-14

nm-Scaled Motion of Charge Carries

Probed by Microwaves

VedantDakaVedantDakaVedantDakaVedantDakaVedantDakaEx-Student , B.Sc.(Hons) PhysicsEx-Student , B.Sc.(Hons) PhysicsEx-Student , B.Sc.(Hons) PhysicsEx-Student , B.Sc.(Hons) PhysicsEx-Student , B.Sc.(Hons) Physics

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

The key to the successful future oforganic semiconductors is to realize amobility equivalent to that of Si-basedmaterials. Organic conjugated mole-cular crystals have been reported tooften exhibit higher values of mobility(>10 cm2V-1s-1) than amorphoussilicon (1~10 cm2V-1s-1) which isquite reasonable when considering thefar higher mobility values reported forcarbon-based graphenes, fullerenes,and carbon nanotubes. To date, themethodo-logies of time-of-flight(TOF), or field-effect transistor (FET)are often the choices for the deter-mination of the values of mobility inthe organic materials.

However under these methodo-logies, applied strong external electricfield leads long range translationalmotion of carriers in the direct-current(DC) mode, and hence the transportof carriers is often disturbed by thepresence of impurities, disorders ordefects in the materials. Recently thereare developed time-resolved micro-wave conductivity (TRMC) measure-ment for the determination of themobility in the materials. Unlikely to

the DC techniques of TOF and FETwhere the translational motion ofcharge carriers induced by the externalelectric field, an alternating-current(AC) method of TRMC is probingthe motion of charge carriers on con-jugated molecules and their assemblieswithout contacts (electrodeless).

This has been applied to elucidatethe intrinsic value of mobility freefrom the above mentioned “distur-bing” processes. The size of the area isdepending on the frequency of the ACelectric field and the mobility ofcharge carriers, and the “tuning” of thesize by the frequency can deduce notonly the value of mobility but also itsdependence on the “shape” of themolecules and the conjugated mole-cular orbitals. In the present times,comprehensively the mechanisms ofcharge carrier transports in thematerials in view of what the deter-minant processes of the charge carriertransport by combining a variety ofmeasurement techniques of chargecarrier mobility in organic conjugatedmaterials.

Page 21: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 21

The proper use of things variesaccording to time, place and person.One must be progressive in thepractical use of every object, every

idea. Through progressive scientificresearch we have to make increasinglygreater use of human potentials. In anera of advanced science, the use oftools and apparatus from a lessdeveloped era is by no means a sign ofprogress. The use of developed toolsand materials, evolved throughdynamic and progressive imagination,may create small or large obstacles inthe way of society; you will have toface them courageously. Throughfight and clash you have to march onto victory, to the path of vindicationof universalism, the cherished goal ofyour life.

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Today some people claims that scienceis the root of all evils and that frequentnew scientific discoveries andinventions have been creating quarrelsand dimensions in human society,thereby pushing the whole humancivilization along the path ofdestruction. It is evident that thosewho criticize science, in reality wantto turn the onward current of lifebackward. This is wholly inimical toprogress. Such an endeavor isindicative of a negative mentality.

If science remains completely inthe hands of materialists, the con-sequence will be hopelessness anddespair. If con-flicts amongdifferent classesgo on unabated,people will even-tually realize thatonly sadviprascan be the leaderof society. Themajority of individual as well as socialproblems can be solved by sadviprasthrough the proper cultivation ofscience.

Science and Spirituality

Swetank BhartiSwetank BhartiSwetank BhartiSwetank BhartiSwetank Bharti

Ex-Student, B.Sc.(Hons) PhysicsEx-Student, B.Sc.(Hons) PhysicsEx-Student, B.Sc.(Hons) PhysicsEx-Student, B.Sc.(Hons) PhysicsEx-Student, B.Sc.(Hons) Physics

Page 22: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

22GRAVITY 2013-14

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

The light powered by Gravity isdeveloped by two London-baseddesigners Martin Riddiford Martin Riddiford Martin Riddiford Martin Riddiford Martin Riddiford and JimJimJimJimJimReeves. It is Reeves. It is Reeves. It is Reeves. It is Reeves. It is a light source thatoperates on the stuff that surroundsus-earth rocks or sand –with thehelping hand of Gravity.

The Gravity light is simplycharged by a bag that is filled witharound 9 Kg of material and hungfrom a cord below the light. As thebag descends, a series of gears insidethe device translates this weight intoenergy, providing 30 minutes oflight.The light strength can beadjusted from strong task lightning toa longer-lasting low-level glow andtwo terminals on the front allow it tobe used as a generator so it canrecharge other devices including radio& batteries.The total three-secondpull on this rope can peep the LEDbulb running up to 30 minutes.

Ø Why it is required?Why it is required?Why it is required?Why it is required?Why it is required?

The problem of lighting the remoteparts of the developing world in pasthas been tackled with everything fromsolar-powered lamps to rechargeablebatteries but all of them require

relatively expensive kit or physicaleffort by the user. Statically Statically Statically Statically Statically the WorldBank estimates that 780 millionwomen and children around the worldinhale a volume of smoke equivalentto smoking two packets of cigarettesa day-leading to the statistic that 60%of female lung-cancer victims indeveloping nations are non-smokers.The fumes also cause eye infections& cataracts, while 2.5 million peopleper year suffer severe burns fromkerosene lamps in India alone.It alsocomes with a huge financial burden:the cost of kerosene for lighting alonecan account for 20% of householdincome.

Ø BenefitsBenefitsBenefitsBenefitsBenefits

• No running cost.

• Long lasting

• Can be used over &over again,anytime.

• Such applications are viable forcountries that do not have stable& reliable electricity access.

• Freeing billions of poor peoplewho current rely on biomass fuelslike kerosene.

Gravity Light (Bulb Power by Gravity

Bhartendu PapnaiB.Sc. Physics (Hons.), 5th sem

Page 23: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 23

When you are not paying attentionin your Physics Class and you open anews website on your mobile andsuddenly read this news:

“An internatiional team ofscientists said on Thursday thatthey had recorded sub- atomicparticles travelling faster thanLight- a finding that couldoverturn Einstein’s long acceptedfundamental laws of universe”

How would you react? I guessyour first reaction would be “theexperiment ought to be wrong!”. ButI was more happy than amazed. Whatif it was indeed true that particlescould travel faster than light?. It wouldbe a breakthrough for the physicistsacross the world. It would mean thatwe are back in the 16th century andthat modern physics is no moremodern. It requires some changes, orat least we need to find ways to fix it.

This is all because of thesubatomic particles, NEUTRINOS.Neutrinos are tiny elementaryparticles having negligible mass andthey were always known to be able totravel almost at the speed of light.Millions of neutrinos arriving fromspace, mainly the sun, strike our body

and pass through it. The mostcommon type is the electron neutrinoand they are produced by beta decayinside the nuclei of atoms.

The Opera Neutrino Experiment,recently conducted by CERN , madeneutrinos popular. In this experiment,which was conducted on muonneutrinos, they calculated the time theneutrinos take to travel from theirpoint of origin at CERN in Geneva,to the Grand Sasso Lab in Italy. Thetravel distance is 730 kms at theneutrinos appear to be able to coverthis at a speed faster than that of alight. (Light would have covered thesame distance in around 2.4thousandths of a second, but theneutrinos took – 60 billionths of asecond less than light beams wouldhave taken).

Einstein, In his Special Theory ofRelativity, asserted that nothing cantravel faster than light. Laws ofNature, as we know it today, forbidanything from going faster. Why didhe choose only Light? It is not lightthat is so significant that it holds thespeed record. But the way space andtime themselves are interwined in ouruniverse implies that there is a

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Light Came Second ?

Digvijay Sing TomarDigvijay Sing TomarDigvijay Sing TomarDigvijay Sing TomarDigvijay Sing Tomar

B.Sc (Hons.) PHYSICS 3B.Sc (Hons.) PHYSICS 3B.Sc (Hons.) PHYSICS 3B.Sc (Hons.) PHYSICS 3B.Sc (Hons.) PHYSICS 3RDRDRDRDRD YEAR YEAR YEAR YEAR YEAR

Page 24: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

24GRAVITY 2013-14

maximum speed limit beyond whichthe laws of Physics break down. Thisspeed happens to be 299792458 m/sin our universe. Light, because it hasno mass, is able to travel at this speed.

Now imagine a moving vehiclewith a velocity spiraling to the speedof light and that we are hauling moreand more energy in and trying to getit faster. But it’s still bumping againstthe speed of light. So where does allthis energy go? It goes into the massof an object. The vehicle actually getsheavier. The most importantconsequence of the equations of

special relativity is how energy andmass are related. In his miracle year1905, Einstein showed that mass canbe converted into energy and vice-versa .Mass and Energy are relatedthrough E=mc2. This equation is oneof the world’s famous, simple andpowerful equations. It gives a uniquedefinition of ‘matter’. MichioKakudefines matter as nothing but thecondensation of vast amounts ofenergy. But could Einstein have beenwrong? And if he is wrong, then whatabout the experiments which hadproven Relativity Theory correct. If

the Opera experiment is flawless, thenwhy didn’t any of the other neutrinoexperiments show such a result? Thesefew questions are in the minds of everyphysicist and they are carefullyexamining everything not leaving aniota of detail unchecked. Some ofthem have already come out with theirtheories, with some in favour andothers against. And yet, till today,there has been no unanimousconsensus.

Nobel Prize winner SheldonGlashow has predicted that such fasterthan light particles would have to beradiating electrons and their anti-particle positron all along theirjourney from Geneva to Italy via aprocess called Vacuum CerenkovRadiation and hence lose energy.Some physicists, with the help ofString Theory, have predicted thatneutrinos, while travelling, traversesan alternate dimension, i.e. they takea shortcut covering a distance lesserthan the actual length hence the timetaken by them is less as compared tothat of a light beam ,because lightparticles are not theoretically expectedto exhibit any such phenomenon. Butfor now, it’s all predictions andtheories. The experiment is still beingrepeated and is under scrutiny and thestudy is going on. Einstein’s ideas havebeen carefully examined for years andit will be very sad if one experimentdestroys it all!

Page 25: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 25

Pros and Cons of Nuclear Power

Saurav SarkarSaurav SarkarSaurav SarkarSaurav SarkarSaurav SarkarB.Sc.(Hons.) Physics, 5B.Sc.(Hons.) Physics, 5B.Sc.(Hons.) Physics, 5B.Sc.(Hons.) Physics, 5B.Sc.(Hons.) Physics, 5thththththsemsemsemsemsem

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

The only clean, safe energy source

capable of ensuring the continuation

of our Industrial civilization while

protecting the environment…

BenefitsBenefitsBenefitsBenefitsBenefits

Ø Nuclear energy is a clean, safe,

reliable and competitive energy

source.

Ø Source of energy that can replace

a significant part of the fossil fuels

(coal, oil and gas) which massively

pollute the atmosphere and

contribute to the greenhouse

effect.

Ø Nuclear medicine:Allow doctors

to make a quick, accurate

diagnosis Radiotherapy can be

used to treat some medical

conditions, especially cancer.

Ø Radioisotope thermal generators

(RTGs) are used in space

missions. The Voyager space

probes, the Cassini mission to

Saturn, the Galileo mission to

Jupiter and the new horizons

mission to Pluto all are powered

by RTG.

Nuclear Power: Risking a Comeback?Nuclear Power: Risking a Comeback?Nuclear Power: Risking a Comeback?Nuclear Power: Risking a Comeback?Nuclear Power: Risking a Comeback?

As per an article given in TIME: In

1980s, climate scientists in Russia and

the U.S theorized that all-out Nuclear

war between the superpowers would

results in a “Nuclear winter”, as smoke

from the atomic explosions blackened

the sky and sent summer temperatures

plummeting below freezing …

Is Nuclear power: Safe ?Is Nuclear power: Safe ?Is Nuclear power: Safe ?Is Nuclear power: Safe ?Is Nuclear power: Safe ?

Serious Nuclear Power plant accident

includes:

• The recent Fukushima Daiichi

nuclear disaster (2011), where

release of significant quantities of

radioactive material within an

installation with a high

probability of significant public

exposure…

• Chernobyl disaster in 1986 (in

the Soviet Union, now in

Ukraine)…

Page 26: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

26GRAVITY 2013-14

• Three Mile Island accident in

1979 (in Pennsylvania, US).

Facts fileFacts fileFacts fileFacts fileFacts file

Outlaw labs once wrote about the

Manhattan project where the first

working bomb was created. At

5:29:45 (mountain war time) on July

16th, 1945, in a white blaze that

stretched from the basin of the Jemez

mountains in northern New Mexico

to the still-dark skies, the Gadget

(code-named as such during its

development) ushered in the atomic

age. The characteristics mushroom

cloud of radioactive vapor due to the

blasts materialized at 30,000 feet.

Beneath the cloud, all the remained

of the soil at the blast site were

fragments of jade green radioactive

glass… all of this caused by the heat of

the reaction.

WarfareWarfareWarfareWarfareWarfare

Ø Hiroshima: A Uranium bomb

nicknamed “Little BoyLittle BoyLittle BoyLittle BoyLittle Boy” was

dropped on Aug 6th, 1945.In a

flash of instant, 66,000 people

were killed and 69,00 people were

injured by a 10 kiloton atomic

explosion.

Ø Nagasaki: A Plutonium bombnicknamed “Fat ManFat ManFat ManFat ManFat Man” wasdropped on Aug 9 th, 1945.39,000 were killed, over 25,000were injured.

TO CONCLUDE:TO CONCLUDE:TO CONCLUDE:TO CONCLUDE:TO CONCLUDE:

Ø Well designed, well constructed,

well operated and well

maintained nuclear energy is not

only clean, but it is also safe,

reliable, durable and competitive.

Willebrord Snellius

(1580 - 1626)

His Law of Refraction was

published 70 years after he

died. This Law of Refraction is

called the Snell’s law.

Satyendra Nath Bose (1894 - 1974)

Bose hailed from India. While giving a lecture to his students, he realized

that there is a discrepancy in the theory of radiation. Thus, he wrote a

letter to Albert Einstein, stating the discrepancy. Einstein agreed and

extensively worked upon his idea, which led to the development of Bose-

Einstein condensate. After that, many related concepts like bosons,

Bose-Einstein statistics came into existence.

Page 27: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 27

Alpha,beta,theta,gammaThis all is not a drama ,

This is physics

Differentiation and integration

,Acceleration or uniform motion

This is physics

Reflection, refraction and

Which all means a great confusion

Gravitational or planck’s constant,

Easy to forget difficult to understand

That, for sure, is physics

Various laws and several theorems

And many more numerical

Which put us in great troubles

This is physics

Force,work,strain and stress

Which all make us restless

This all make us confess

That this physics is a stress

Oh! Physics

Ashish KumarAshish KumarAshish KumarAshish KumarAshish Kumar

B.Sc. physical science 3rd yrB.Sc. physical science 3rd yrB.Sc. physical science 3rd yrB.Sc. physical science 3rd yrB.Sc. physical science 3rd yr

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Georg Ohm (1776 - 1856)

Ohm became a household name today for his most important

contribution, the Ohm’s Law.

Page 28: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

28GRAVITY 2013-14

Albert Einstein was born on 14 March1879 at Ulm in Württemberg,Germany. He began his s s s s schooling atLuitpold Gymnasium. Rather thanjust memorizing facts and dates, hepreferred to ponder questions. Hefound regular teaching schooling to

Einstein Life and his Achievements

Anju DeshwalAnju DeshwalAnju DeshwalAnju DeshwalAnju Deshwal

B.Sc. Physical Science, 5B.Sc. Physical Science, 5B.Sc. Physical Science, 5B.Sc. Physical Science, 5B.Sc. Physical Science, 5thththththsemsemsemsemsem○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Johannes Diderik van der Waals (1837 - 1923)

He established the equation of state for liquids and gases that

describes the behavior of gases and their condensation on the liquid

phase. He received the Nobel prize in 1910. Some more terms like,

‘van der Waals forces’, ‘van der Waals molecules’ and ‘van der Waals

radii’ are coined after his name to honor his accomplishments.

be strict and boredom. Later on, hecontinued his education at Aarau,Switzerland. In 1901, he gained hisdiploma in Swiss Federal PolytechnicSchool in Physics and Mathematics.In 1905, he obtained his doctor’sdegree, but was unable to find ateaching post. He joined As aTechnical Assistant in Swiss PatentOffice.

In 1905, while working at thePatent office, Einstein wrote fivescientific papers. In one paper,Einstein theorized that light must notjust travel in waves but existed asparticles which explain Photoelectriceffect. For this theory Einstein alsowon Noble Prize in Physics in 1921.In another paper, Einstein describedBrownian motion. By declaring thatpollen was being moved by water

Page 29: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 29

molecules, he solved the scientificmystery as well as proved the existenceof molecules.

In his third paper, he described“Special Theory Of Relativity” inwhich Einstein revealed that Spaceand Time are not absolutes. The speedof light, rest of Space and Time, allare based on the position of observer.Four years after, his theories were firstpublished, he was finally offered ateaching position at University ofZurich. In 1916, He published hispaper on general theory of relativity.

As Einstein’s fame with scientificcommunities grew, offers for newbetter positions began to pour in. Heworked at German University,University Of Zurich. Instantlyfamous, Einstein was given honorary

Robert Hooke (1635 - 1703)

Hooke’s Law of Elasticity puts forth the relationship between the force

applied to an object and the level of deformation it undergoes. Also,

Hooke was the first person to observe the plants and fossils under a

microscope, and coin the term ‘Cell’.

Lord Ernest Rutherford (1871 - 1937)

He is also known as the father of nuclear physics. He

differentiated the emitted radiations and named them as

alpha and beta. He had also put forth the famous Rutherford

model of atom in 1911.

degree and had been awarded NobelPrize in Physics.

In July 1939,Enistein write a letterto the President Franklin d. Rooseveltto warn him about the potentiallymassive weapon ,Atomic bomb andin response of it, Mahatten Project wasestablished, which was collection ofUS scientists urged to beat Germanyto the construction of a workingatomic bomb. From 1922, until hisend of life, He worked on findings“Unified Field Theory” that couldcombine all the fundamental forces ofPhysics between elementary particles,he never found it. In 1952, Einsteinwas offered the Presidency of Israel butEinstein declining the honourrealizing he was not good at politics.

On 18 April 1955, Einstein died.He was 76 years old then.

Page 30: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

30GRAVITY 2013-14

Isaac Newton was born on 25December 1642 in Woolsthrope inLincolnshire. His father died beforehe was born and in 1645, his mothermarries a clergyman and went to livewith him while Isaac Newton livedwith his Grandmother. When Isaac’sstepfather died in 1665, her motherreturned to Woolsthrope and IsaacNewton went to live with her again.Isaac went to Grantham GrammarSchool. IN 1659, Isaac had to leave,to help his mother in family farm buthe had no interest in running familyfarm, so in 1660, he went to theGraham School again. In 1661, Hewent to Trinity College, Cambridge.

Newton’s Biography

Komal ChauhanKomal ChauhanKomal ChauhanKomal ChauhanKomal ChauhanB.Sc. Physical Science, 3B.Sc. Physical Science, 3B.Sc. Physical Science, 3B.Sc. Physical Science, 3B.Sc. Physical Science, 3rdrdrdrdrd year year year year year

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

He obtains a BA in 1665 but wasforced to flee Cambridge because ofan outbreak of the Plague and hereturned temporarily to Woolsthrope.

A falling apple in the Orchard atWoolsthrope had supposedly ledNewton to consider whether the forcethat caused the apple to fall on theEarth was the same force thatgoverned the motion of the Moonaround Earth and of the Planetsaround Sun. In 1667, he returned touniversity and was elected a fellow ofTrinity College and also a member ofRoyal Society. In 1668, he invented areflecting telescope. Isaac Newtonbecame Lucas Ian Professor ofMathematics in 1669. In 1689-1690,Isaac Newton was MP for CambridgeUniversity.

Isaac Newton published hismaster piece PhilosophiaeNaturalisPrincipia Mathematica in 1687. It setout his Theory of Gravity and Lawsof Motion. In 1701, Isaac resigned hisfellowship and professorship atCambridge. He became President ofRoyal Society in 1703 and in 1704,he published another great work aboutlight . Isaac Newton died on 20 March1727.

Page 31: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 31

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Many companies have found marketfor their small handheld products thatclaim to save 30-40 per cent electricalpower, thereby reducing electricitybill. But can you really save electricityby plugging in a small device?

What is a power saver?What is a power saver?What is a power saver?What is a power saver?What is a power saver?

A power saver (PS) device resembles amosquito-repellent plug-in gadget(like All-out or Goodnight) and ismeant to save power in houses, shopsand small offices. It is plugged into asocket to work in parallel with otherappliances connected to the electricalcircuit of an establishment.

Benefits of using it.Benefits of using it.Benefits of using it.Benefits of using it.Benefits of using it.

Power savers primarily save electricalpower, so it will help us in reducingour electricity bill. However, thesealso improve the quality of inputelectrical signal, and thus enhancethe life-span of householdappliances.Thus, it is beneficial forthe utility company providingelectrical supply. It is absolutelylegal. Using a power saver does notmean fiddling with the electricitymeter. A power saver is connected

Power Saver : Can it Really Help toReduce our Electricity Bill

Vikas BeliwalVikas BeliwalVikas BeliwalVikas BeliwalVikas BeliwalB.Sc. Phy (Hons.) 1B.Sc. Phy (Hons.) 1B.Sc. Phy (Hons.) 1B.Sc. Phy (Hons.) 1B.Sc. Phy (Hons.) 1stststststyearyearyearyearyear

to the electrical circuit after the meter,which means it does not hamper ormanipulate meter functioning.

What is inside a power saver?What is inside a power saver?What is inside a power saver?What is inside a power saver?What is inside a power saver?

The device has a big PFC capacitorand a current harmonic filter circuit.Some devices also have metal-oxidevaristors (MOVs) that act as transientsuppressors, protecting the circuitfrom voltage spikes. A series connectedthermal fuse is used with MOVs toprovide protection in the event ofshort circuit. Power savers come withintegrated voltage stabilization circuittoo. A light-emit- ting diode (LED)is used to indicate power-on condi-tion.

Page 32: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

32GRAVITY 2013-14

WorkingWorkingWorkingWorkingWorking

Most of the household appliancessuch as refrigerator, air-conditioner,fan, fluorescent tube light and mixergrinder are inductive in nature.Inductive loads create a phasedifference between the AC currentand voltage. The wires and thetransformers are also inductive innature. Inductive loads requirereactive power to work, whichincreases the current that the sourceprovides. This can be explained veryclearlyfrom the Mac’s dragginganalogy shown in Fig. The true poweror the actual power to drag the load iskW in forward direction .Power factoris the cosine of the phase differencebetween the current and the voltage.When the voltage and the current arein phase with each other in an ACcircuit, the electrical energy drawnfrom the source is fully converted intoanother form of energy in the load,and the power factor is unity. Whenthe current lagsthe voltage, the energyis wasted in reactive power andthepower factor isless than unity, makingthe system less efficient. Power factorcorrection is a method in which a

reactive load is introduced in theopposite direction to cancel out thereactance of the inductive load byusing a power-factor-correctioncapacitor. In India, the power factoris usually in the range of 0.7-0.8depending on the house and load. Thecapacitors used forPFC are a specialtype of low-voltage capacitors.

Under what conditions is the powerUnder what conditions is the powerUnder what conditions is the powerUnder what conditions is the powerUnder what conditions is the powersaver really effective?saver really effective?saver really effective?saver really effective?saver really effective?

You can save only on those deviceswhich contribute to the inductiveload, such as refrigerators, washingmachines, motors and air-conditioners. Again, the percentagesaving depends on many otherparameters also. Power savers save onlythe power that is wasted or is notuseful. In old houses, wear and tear incopper wires may result in currentleakage, thus adding to the power loss.In such houses, power savers mayfacilitate better savings. However, inhouses with new wiring, thepercentage saving from power saversis relatively less. . Areas with highvoltage fluctuations like shops andrestaurants can gain additional savingsfrom power savers.

Amedeo Avogadro (1776 - 1856)

Contribution of Avogadro was the Avogadro’s law. As a tribute to

his work, a constant Avogadro’s constant or number was named

after him.

Page 33: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 33

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Physics - the study of matter, energyand their interactions – is aninternational enterprise, which playsa key role in the future progress ofhumankind. The support of physicseducation and research in all countriesis important because: physics is andexciting intellectual adventure thatinspires young people and expands thefrontiers of our knowledge aboutnature.

Physics is a creative subject, theconcepts of physics don’t come easily.Someone has to come up with a theoryto begin with. This is just as much acreative process as composing music.But where physics, and science ingeneral, differ from the Arts is that noone will accept your theory unless youhave some way of testing its validity.Experimental physicists sometimeshave to be enormously creative incoming up with methods of testingtheories and measuring things in theworld around them. For example, howdo you tell that there is a planetorbiting a star that is so far away thatit appears as nothing more than a spec

of light in even the most powerfultelescopes? Few importances ofphysics to man and the society are -

Physics Improves HealthPhysics Improves HealthPhysics Improves HealthPhysics Improves HealthPhysics Improves Health

In medical technology, positronemission tomography (PET) Letsneurologists see how energy flowsinside the brain to see where problemscould be occurring.

Physics Connects the WorldPhysics Connects the WorldPhysics Connects the WorldPhysics Connects the WorldPhysics Connects the World

The telecommunications industry,including the development of theinternet, has benefited from physicsresearch in telecommunications fromradio waves to fiber optic cable.

Physics Improves Technology;Physics Improves Technology;Physics Improves Technology;Physics Improves Technology;Physics Improves Technology;

The computing industry depends onphysics research in semiconductorsand magnetism in order to buildprocessors and disk ever smaller anddenser.

Physics Drives ProgressPhysics Drives ProgressPhysics Drives ProgressPhysics Drives ProgressPhysics Drives Progress

Physics research benefits thetransportation industry in everything

The Importance of Physics to Man and

the Society

KiranKiranKiranKiranKiranB.Sc. Physics (Hons.) First YearB.Sc. Physics (Hons.) First YearB.Sc. Physics (Hons.) First YearB.Sc. Physics (Hons.) First YearB.Sc. Physics (Hons.) First Year

Page 34: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

34GRAVITY 2013-14

from what materials to build cars ofto how to build efficient engines tonavigating using the globalpositioning system.

Physics Clears the AirPhysics Clears the AirPhysics Clears the AirPhysics Clears the AirPhysics Clears the Air

Physics is used in environmentalscience to both detect problems andto build systems that are better for theenvironment with technologies suchas solar power and plasma physics.

Physics Fills the HomePhysics Fills the HomePhysics Fills the HomePhysics Fills the HomePhysics Fills the Home

Many consumer goods developedfrom physics research. CDs arepossible because of refinements in lasertechnology. Many household gadgetshave microprocessors such asmicrowaves & phones.

Physics Designs the FuturePhysics Designs the FuturePhysics Designs the FuturePhysics Designs the FuturePhysics Designs the Future

Research in materials physics has ledto many innovations in the substancesfrom which products are made. Onenow-common material is Teflon®.Other substances are now used tomake many items from sportsequipment to earthquake-resistantbuildings.

Physics Lunches New BusinessPhysics Lunches New BusinessPhysics Lunches New BusinessPhysics Lunches New BusinessPhysics Lunches New Business

The defense department started theGlobal Positioning System (GPS),which uses 24 satellites. GPS waspossible because of the atomic clock.Now GPS technology has many usesfrom being in road maps in cars to

perceiving shifts in the tectonic plates.

Physics is the most Fundamenal ofPhysics is the most Fundamenal ofPhysics is the most Fundamenal ofPhysics is the most Fundamenal ofPhysics is the most Fundamenal of

the Sciencesthe Sciencesthe Sciencesthe Sciencesthe Sciences

It is concerned with the most basicbuilding blocks of all things - fromants to antennas, from quarks toquasars. The study of physics meanstrying to find out what the universe ismade of, and how these things moveand interact with each other. So in onesense, all the other sciences are builton the knowledge gained through thestudy of physics.

Physics is BeautifulPhysics is BeautifulPhysics is BeautifulPhysics is BeautifulPhysics is Beautiful

Physicists love simplicity. They areconstantly striving to find the mostfundamental ideas that can be used todescribe even the most complex ofphenomena. For example Newtonfound that only a very small numberof concepts could be used to describejust about all of the mechanical world- from steam engines to the motionof the planets. Not only is thisbeautiful, it’s downright amazing!

Physics Teaches you to ThinkPhysics Teaches you to ThinkPhysics Teaches you to ThinkPhysics Teaches you to ThinkPhysics Teaches you to Think

This might seem like a strangestatement. The study of all subjectsteach you to think. But becausephysics deals with the most basicconcepts, the application of suchtechniques as “Separation ofVariables” and “The ScientificMethod” are never more clear than

Page 35: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 35

they are in the study of physics. Oncemastered you will find that thesemethods can be applied to all subjects,including the business world and justcoping with everyday life.

Physics g ives you a newPhysics g ives you a newPhysics g ives you a newPhysics g ives you a newPhysics g ives you a newAppreciation of the World aroundAppreciation of the World aroundAppreciation of the World aroundAppreciation of the World aroundAppreciation of the World around

youyouyouyouyou

You can look a rainbow and say“Wow, pretty colors!”, or you canmarvel at the amazing interactionsbetween photons and electrons thatcome together in that particular waywhen light from the sun strikesspherical water droplets in the sky, andthat you perceive as a multicolored arcsuspended in the air. Now that’s awe!

Physics is FunPhysics is FunPhysics is FunPhysics is FunPhysics is Fun

Lastly, studying physics gives you theopportunity of playing with a lot ofreally cool toys!

In addictionIn addictionIn addictionIn addictionIn addiction

Many pioneers in molecular biologywere trained as physicists e.g. Francis

Crick, one of the two discoverers ofDNA.

• A large number of astronomerswere also trained as physicist.

• Without physics, cars wouldn’thave being developed to take usto our various destinations.

• TV’s, Light will not have beeninvented.

• We would not have known aboutspace,

• Computer Games,• How water boils,• Model financial Market,• Shape futuristic buildings and

structures.

Summary & ConclusionSummary & ConclusionSummary & ConclusionSummary & ConclusionSummary & Conclusion

In summary, for all these reasons,physics is an essential part of theeducational system and of an advancedsociety. We therefore urge allgovernments to seek advice fromphysicists and other scientists onmatters of science policy, and to besupportive of the science of Physics.

Lord William Thomson Kelvin (1824 - 1907)

He formulated the first and second Law of Thermodynamics and

improved the reliability of the mariner’s compass. He was knighted

by Queen Victoria, after which he became Sir William Thomson. He

was the one who put forth the correct value of absolute zero as -

273.15 celsius. Also, in his honor, unit of absolute temperature is

known as ‘Kelvin’.

Page 36: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

36GRAVITY 2013-14

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Time Travel

Prashant JoshiPrashant JoshiPrashant JoshiPrashant JoshiPrashant JoshiB.Sc( Hons) Physics 2nd year

for you. If you take a walk around ablock of 100m of each side you willbe 3 femto seconds younger than yourfriend who stayed home. But maybeyou want to time travel more than fewfemto seconds then get ready to yourhead start spinning. I mean theuniverse, general relativity predicts

that if our universe start spinning atvery high speed then it will producetime loops over all places and in thosetime loop it will appear that you aremoving forward in time but actuallyyou will fall into an infinite time loop.It’s a little like to start travellingaround earth and get back to the sameplace after some time due to curvatureof earth but unfortunately ouruniverse does not spin or that’s whatour current physics tells us about ouruniverse.

Time travel sounds like a 70’s sci-fimovie but is it so? Now we are goingto look in the heart of modern physicstoo see whether we will be able totravel in time or not. The best way totravel in time is to do nothing ......because we actually travelling in time,we always travel in future or you can

say that the future is inevitable but it’sa boring way to travel in time.

When we talk about time travelwe think travelling in time withsomeone or something relative to it.If you really want to travel in time thenstart running and you will travel intime relative to someone standing still.It is well known over a single centurythat time and space are twocomponents of single space time andfaster you move the slower time pass

Page 37: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 37

Don’t get disappointed I’m notdone yet I bet everyone of you guysheard about worm holes in sci-fi booksor in Hollywood movies that how avillain tries to kill our hero by goingback in past by creating a worm hole.For starters who doesn’t know whatworm holes are they are hypotheticalbut not physically impossible bridgesthrough space time but the problemis that no one knows how to build oneor ones you built it how to stop it fromcollapsing as many physicists believesthat keeping worm hole open requiresnegative energy but nobody knowshow to create negative energy

although they occasionally slaps thename exotic matter on the conceptand pretend it might exist, well that’stoo bad .Or much better why don’twe create our own black hole I meanGeneral and special relativity tells thatthe more the gravity the slower thetime will pass by doing some of itsbusiness with space time but againcreating a black hole doesn’t seems tobe good idea because they are toomuch violent in nature I mean howcan you control something fromwhich even light can’t escape and Idon’t really think that physicists arein some serious mood to create a blackhole.

James Chadwick (1891 - 1974)

Discovery of neutron was his path-breaking discovery that helped

him bag the coveted Nobel in 1935.

Carl David Anderson (1905 - 1991)

While studying the energy distribution of cosmic-rays for his

doctoral thesis, he discovered positron (positive electron) which

bagged him the Nobel prize in 1936.

Wolfgang Pauli (1900 - 1958)

Establishing the Pauli principle, which is also called the exclusion

principle, Pauli received the Nobel prize in 1945.

Dennis Gabor (1900 - 1979)

He discovered holography in 1947, for which he received the

Nobel prize in 1971. However, it became commercially available

only after 1964.

Page 38: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

38GRAVITY 2013-14

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Terrafoming

Prashant TyagiPrashant TyagiPrashant TyagiPrashant TyagiPrashant Tyagi

B.Sc. (HONS) Physics1B.Sc. (HONS) Physics1B.Sc. (HONS) Physics1B.Sc. (HONS) Physics1B.Sc. (HONS) Physics1ststststst year year year year year

Looking for a new house or a newplanet ?it all boils down to location ,location , location. Here are the bestoptions for future colonies.

MarsMarsMarsMarsMars

The red planet is central to theterraformer’s dreams. It needswarming up though. The key may bethe green house gas CO2. Mars air istoo thin, but dry ice at the poles couldbe melted with orbiting mirrors.There is much more water on themoon: frozen at the poles, and insurface layers and deeper aquifers.Again, solar power could melt it. Itwould take a long time, but may beone day humans will be able to breathefrosty martian air.

VenusVenusVenusVenusVenus

CO2 atmosphere is so thick it exerts

a pressure equivalent to a kilometerunder earth’s oceans. Venus has lostall of its – a key barrier to colonization.To terraformvenus, most of that CO

2

would have to be removed. But venusrotates very slowly; the sun would riseonly once every 117 days. Earth’s sister

world will be orders of magnitudeharder to terraform than mars.

1. Living Quarters

2. Greenhouses

3. Pressurized Habitats

4. Power Plant

5. Water Tank

The ice moonsThe ice moonsThe ice moonsThe ice moonsThe ice moons

Apart from Jupiter’s volcanic moonlo, the larger moons of the outerplanets have tremendous stores ofwater and other volatiles in the formof ice crusts and mantles. On some ofthem, like Europa, there may be liquidoceans beneath the ice. These couldprovide an intriguing environment forcolonists, and they are promisinghabitats for native life. To melt theice, sunlight might have to beconcentrated with vast mirrors.

Page 39: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 39

Comets and asteroidsComets and asteroidsComets and asteroidsComets and asteroidsComets and asteroids

The asteroids, relics of the solarsystem’s formation, are mostly foundbetween mars and Jupiter. But weknow of more than 200 near – earthasteroids (NEAs) that periodicallyapproach us. Some of these representopportunities, some containingprecious metals, water and organiccompounds we have already reachedsome NEAs with unmannedspacecraft. They may be the first targetfor prospectors, with comets to follow.

Pluto-and beyondPluto-and beyondPluto-and beyondPluto-and beyondPluto-and beyond

Follow the water’ will always be themotto of colonists and teraformers.And there is plenty out there. In theasteroids and outer- system moon’sthere is probably several 100 times asmuch water as in earth’s oceans. Plutois one with icy worldlets and massivecomets that may mass as much as 10times all the planets combined. I thedistant future, the possibilities areendless: taking apart massive worldslike Jupiter, or even tinkering with theSun’s workings.

Nikola Tesla (1857 - 1943)

He holds a patent for alternating current induction motor. It is

believed that Tesla is the first person in North America who

accidentally captured an X-ray image.

John Dalton (1766 - 1844)

Dalton is the pioneer of modern atomic theory. Dalton’s law of

partial pressure was put forth in 1801, and has now become very

valuable in the chemistry lab.

Daniel Gabriel Fahrenheit (1686 - 1736)

The everyday household mercury thermometer was developed by

him. He also determined the temperature scale called Fahrenheit,

which was named after him.

Blaise Pascal (1623 - 1662)

His inventions include the first calculation machine know as the

Pascal’s calculator. His other inventions were hydraulic press,

followed by a syringe.

Page 40: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

40GRAVITY 2013-14

Higgs TheoryHiggs TheoryHiggs TheoryHiggs TheoryHiggs Theory

On July4, 2012, Scientist at CouncilEuropean Pour La Recherché Nucleaire(CERN) announced that they had founda particle that behaved the way they expectthe Higgs Boson to behave the standardmodel (Cosmos Works).

This model comes by way of particlePhysicists, a first scientists discovered theatoms, then protons neutrons and electrons and finally quarks and leptons.But, the universe does not contain only matter; it also contains forces that allabout that matter. This standard models was developed in the early 1970, outentire universe is made up of 12 different matter particles and four forces amongthose 12 particles-6 quarks and 6 leptons. Quarks make up protons andneutrons, while leptons include electron and electron neutrino, its neutrallycharged counterparts.

Scientist thinks that leptons and quark are indivisible. Standard model alsoacknowledges four forces i.e. gravity, electromagnetic, strong and weak. Physicisthas predicted the existence of certain particles years before they were variedempirical. This model had missing term the Higgs boson.

What is God Particle?What is God Particle?What is God Particle?What is God Particle?What is God Particle?

The God Particle is the nick name of Higgs Boson, asubatomic particle. Some particle like proton and neutronshave mass but photons do not. God particle (Higgs Boson)gives mass to the matter. Each of the sub-atomic particlescontributes to the forces that cause interactions. Science isnot entirely sure why some particles seem mass less and other

GOD PARTICLE

Sanjeet KumarSanjeet KumarSanjeet KumarSanjeet KumarSanjeet Kumar

B.Sc. (HONS.) Physics 3 B.Sc. (HONS.) Physics 3 B.Sc. (HONS.) Physics 3 B.Sc. (HONS.) Physics 3 B.Sc. (HONS.) Physics 3rdrdrdrdrd yr yr yr yr yr○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○

Page 41: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

GRAVITY2013-14 41

are massive. The standard model predicts that the higgs-boson particle producethe effect of mass.

Its name arose when the book the God Particle: If the Universe is the Answer,what is the Question? By Leon-Lederman was published. The Higgs BosonThe Higgs BosonThe Higgs BosonThe Higgs BosonThe Higgs Bosonor Higgs particle is an elementary particle initially theorized in 1964 andor Higgs particle is an elementary particle initially theorized in 1964 andor Higgs particle is an elementary particle initially theorized in 1964 andor Higgs particle is an elementary particle initially theorized in 1964 andor Higgs particle is an elementary particle initially theorized in 1964 andtentatively confirmed to exist on 14 March 2013tentatively confirmed to exist on 14 March 2013tentatively confirmed to exist on 14 March 2013tentatively confirmed to exist on 14 March 2013tentatively confirmed to exist on 14 March 2013. The discovery has beencalled ‘monumental’ because it appears to confirm the existence of the higgsfield, which is pivotal to the standard model and other theories within particlephysics. It would explain why some fundamental particles have mass when thesymmetries’ controlling their interactions should require them to be mass less,and linked to this why the weak force has a much shorter range theelectromagnetic force. The large hadrons colliders able to circle higgs bosonand other particles for observation and study.

On 04 July 2012, it was announced that a previously unknown particlewith a mass between 125 and (134.2 and 136.2 emu) had been detected. It wasalso confirmed it have positive parity and zero spin. This is first unknownscalar particle discovered in nature. One of the most important discoveries inparticle physics of the last 25 years has possibly just been made by experimentalistat CERN, the giant laboratory just outside of Geneva on the border ofSwitzerland and France

If the properties of higgs are confirmed the picture of the fundamentalparticle forces will have been completed. That picture is known as the standardmodel. The standard model of Particle Physics provides a description ofmicroscopic matter and their fundamental interactions.

All matter is comprised of quarks and leptons. Three quarks bind to form

the proton and neutron. The neutron and protons stick together to form nuclear.Leptons appears in nature in two types-(i) Electrically charged and(ii) electricallyneutral. Neutral leptons are called neutron and hardly interacts with matter atall.

There three charge leptons-electrons (lightest) (it is negatively charged, areattracted to nuclei). Since atoms make up everything in the world quarks andleptons are the fundamental building blocks of nature.

Page 42: Gravity - people.du.ac.inpeople.du.ac.in/~mrana/physics-society/gravity/Gravity IV 2013.pdf · 2013-14 3 GRAVITY Message From the Desk of the Principal I am glad to know that the

42GRAVITY 2013-14

Every car have many electrical systems, in your car. These are ignition system,the charging system, battery and some that you do not ever think about. All ofthese will require a constant and safe electric current supply with perfect timing.

1. Battery1. Battery1. Battery1. Battery1. Battery

An electrical reservoir which is used to storeelectrical energy until it is needed by the vehicle’sstarting system to crank the engine and alsosupplements the electric during periods of highdemand. Even if your car’s engine is off, thebattery provides the required power to the restof the system

2. Charging System2. Charging System2. Charging System2. Charging System2. Charging System

This is the main part of the electrical system which consists of three maincomponents: the belt-driven alternator, various electrical circuits, and a voltageregulator. The alternator supplies power to the electrical system and rechargesthe battery after your car has started.

3. Starting System3. Starting System3. Starting System3. Starting System3. Starting System

This is main electrical power consumes more than any other system in yourcar. It consists of three components which work in tandem: the ignition switch,the starter relay and the starter motor. The ignition switch controls the startersolenoid, which activates the starter motor. The starter motor then turns theengine until your car starts.

A simple spark, when delivered at precisely the right moment, can meanthe difference between a smooth running and powerful engine that operatescleanly and an engine that runs rough, lacks power and produces unnecessaryemissions. Your car needs attention if :• Car is hard to start, or take too long time before starting• Car misfires, Your fuel mileage is not what it used to be• Car has lost power or it is sluggish

Vehicle’s Electric Charging System

Sagar DahiyaSagar DahiyaSagar DahiyaSagar DahiyaSagar DahiyaB.sc(Hons.) PhysicsB.sc(Hons.) PhysicsB.sc(Hons.) PhysicsB.sc(Hons.) PhysicsB.sc(Hons.) Physics

○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○