DO NOW (3/7/14):

1. What is a photon?

2. What are some characteristics of photons?

3. Does light interact with matter as a particle or a wave? Justify your answer.

STRAIGHT OUTTA COMPTON THE COMPTON EFFECT

3/7/14Pass in your DO NOWs

THE COMPTON EFFECT (COMPTON SCATTERING)

The Compton effect is a form of ionization.

What is an ion?

An ion is an electrically charged atom or group of atoms.

Compton Scattering ionizes particles through the emission of an electron

APPLICATION

How can this be used?

- Ion Propulsion Engines

- Particle Accelerators

- CT Scans / X-rays

THE COMPTON EFFECT

Result of a high-energy photon colliding with a target.

THE COMPTON EFFECT (COMPTON SCATTERING)

http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/Graphics/Flash/compton.swf

The electron is irradiated with a photon.

The Scattered Photon comes off as Radiation.

THE COMPTON EFFECT (COMPTON SCATTERING)

This lends support to Einstein's photon theory, rather than wave theory.

Compton Scattering was first demonstrated in 1923 by Arthur Holly Compton.

Scattered radiation experiences a wavelength shift. X-rays increase in wavelength when scattered.

How does the wave for the incident photon compare to that of the scattered

photon?

COMPTON SHIFT: (WRITE ON BACK)

)cos-(1m

h='

0

c

)cos-(1 =-' c

Is the change in wavelength of scattered photon

λ = incoming photon wavelength λ' = scattered photon wavelength

COMPTON WAVELENGTH

c0C m

h=

Where m0 is the mass of the target particle

Example: Mr. Davis detonates an EMP weapon to destroy some robots. The bomb releases gamma rays with a wavelength of 3x10-11 m and the deflect with nitrogen and oxygen electrons at an angle of 45 degrees. What is the wavelength of the scattered gamma-rays?

)45cos1(1000243.)103(' 911 mxmx

)cos-(1=' c

-1311 7.19x10)103(' mx

m-113.07x10'

Volunteer for:

GivensEquation )451000243.103 911 mxmx c

CLASSWORK

Two problems (9&10) require the use of photon energy, from the photoelectric effect unit, we will learn more about this next week.

If you finish these problems today I will come around and give you extra credit.

Spend the rest of class working on your classwork.

There is a bonus assignment if you finish early.

DO NOW (3/10/14)

X-rays of wavelength 0.456nm are scattered from a block of carbon.

What will the Compton Shift be at:

a) 0˚b) 15˚c) 45˚

CLASSWORK

At the end of class there will be a one problem Check for

Understanding that is related to your Do-Now.

You have all of class to ask questions.

Don’t forget you can use the Parking Lot.

I will put all necessary equations and variables on the board.

CLASSWORK

Continue working on your classwork from Friday.

Questions 8,9, and 10 use energy which we will learn tomorrow. Extra Credit if

you solve them today.

If you finish early there is a bonus and you can start tomorrow’s classwork.

Check for Understanding last 10 minutes of class.

CHECK FOR UNDERSTANDING (3/10/14)

X-rays of wavelength 0.789nm are scattered from a block of carbon.

What is the angle of reflection of the photon if the Compton Shift is:

a) 0.000326nmb) 0.001215nmc) 0.002430nm

DO NOW (3/11/14) ON YOUR NOTESHEET:(5 MINUTES)

A 0.123-nm photon collides with a stationary electron. After the collision, the electron moves forward and the photon recoils backwards.

1)Draw a picture of the situation.2)What is the angle between the

scattered photon and the electron?3)List three things that you have

learned about that are CONSERVED.

Do this on your notesheet but I’m going to stamp your Do Now paper.

GUIDED NOTESHEET

Looking at the problem on the notesheet, what are

we solving for?

The Kinetic Energy of the Electron

GUIDED NOTESHEET

Lets start by looking at the motion of the electron:

When is the electron moving: Before the collision?

After Collision?

The electron starts out as Stationary After the collision it’s moving

Where does the electron get the energy

to start moving?

The collision with the photon!

CONSERVATION

The electron gains energy from it’s collision with the photon.

Is that energy created from nothing? Where does it come

from?

The photon gives the electron some energy.

INCIDENT PHOTON

has energy E and linear momentum p:

hc

E c

Ep

SCATTERED PHOTON

has energy E :

'hc

E

THE COMPTON EFFECT

The photon gives part of its energy to one of the electrons, in the form of KE

Total energy and momentum must be conserved.

LOSS IN PHOTON ENERGY = GAIN IN ELECTRON ENERGY

KEelectron = Eincident photon – Escattered photon

Equivalent formulas are on your notes sheet!

EXAMPLE (5 MINUTES):

a) A 70-keV photon is Compton-scattered by an electron. What is the wavelength of this initial photon?

b) If the scattered photon comes off at 27, what is its wavelength after being scattered?

BACK TO THE GUIDED NOTESHEET

What variables do we have so far?

The Initial wavelength of the photon

The Angle between the photon and electron

GUIDED PROBLEM

We are trying to solve for the energy of the scattered electron, how does this relate the energy lost by the photon?

What are we solving for?

LOSS IN PHOTON ENERGY = GAIN IN ELECTRON ENERGY

GUIDED PROBLEM

We now need the energy of the scattered photon, what equation do we want to use?

To solve for the energy, what variable do we need to solve for?

This means we need to solve for λ`

'hc

E Knowing that Photon Energy is transferred to the electron, what

should we try to solve for now?

SOLUTION (5 MINUTES) Givens:

Equation:

We need:

)cos-(1=' c

18000243.123. nmnm c

____________` electronE

Solve for λ`

Electron Energy:

)cos-(1=' c

.1278nm .123cos(180))-00243(1.='

eVE 3931278.

1240

123.

1240

PRACTICE:

Please use the rest of class to work on your

classwork. It will be graded for accuracy.

It is due on Friday.

Exit Ticket at the end of class.

EXIT TICKET (3/11/14)

A 0.234-nm photon collides with a stationary electron. After the collision, the electron moves forward and the photon recoils backwards.

Calculate the Kinetic Energy of the electron.

CONCEPTUAL QUESTIONS (3/12/14) (5 MINUTES)

In Compton Scattering

1) What happens to energy lost by the incident photon?

2) The wavelength of the scattered photon (increases/decreases) after collision with the electron.

3) What is the equation for the energy of a scattered electron?

DO NOW (3/12/14) (8 MINUTES)

1) What is the equation for the energy of a scattered electron?

2) A 0.234-nm photon collides with a stationary electron. After the collision, the electron moves forward and the photon recoils backwards.

a) Calculate the wavelength of the scattered photon.

b) Calculate the Kinetic Energy of the electron.

108 eV

GROUP QUIZ REVIEW

I’m going to check one paper per group.

Competition for Quiz Extra Credit

First Three groups to finish the worksheet with every problem

correct get Extra Credit

GROUP QUIZ REVIEW

When you finish a page raise your hand and I will come check it.

If you get stuck, skip that problem and come back to it later.

PERIOD 4

CortneyStephanieAmbe

EmilieShazaadMaria

RakemImaniAlexis

India HMyeasher

Tyler

BriahnaChaletAyona

JadeAyanna

Alex

HeavenJasir

Corey

JasmineIndia CShaitia

EmmerandaCiairahJohnelle

PERIOD 6

Sade`BriannaBrooke

ImaniVaughnMaria

MorganUyenCharles

KateKendall

Teira

ShaolinTristanKayla

TariqKareemDe’Aira

ShaniaChelseyJustin

PERIOD 7

DeniseAyanaMariah

SharaeMaulleaJermira

JaleelLeezAlvin

Ti-TaiyonnaShamarChance

Daja

KateshaRubi

Courtnei

Will DTatiana

Malcolm

Will HTa’es

Kyallah

MichaelShemLeon

CamilleStephanieQuinones

GROUP QUIZ REVIEW

When you finish a page raise your hand and I will come check it.

If you get stuck skip that problem and come back to it later.

I’m going to check one paper per group, so make sure one paper has

all the solutions.

COMPTON SHIFT:

)cos-(1m

h='

0

c

)cos-(1 =-' c

The change in wavelength of scattered photon

THE COMPTON EFFECT

Do Now (3/13/12): Photons are released with a wavelength of 4.7x10-11

m and they deflect with nitrogen and oxygen electrons at an angle of 60 degrees. What is the wavelength of the scattered gamma-rays?

EXAMPLE:

A 70-keV photon is Compton-scattered by an electron. If the scattered photon comes off at 27, what is its wavelength?

DO NOW (3/14/12):

A 60 keV photon is Compton-scattered by an electron. If the scattered photon comes off at 36, what is its wavelength?

EXAMPLE:

A 210-nm photon collides with a stationary electron. After the collision, the electron moves forward and the photon recoils backwards. Calculate the kinetic energy of the electron.

DO NOW (3/15/12):

A 0.23-nm photon collides with a stationary electron. After the collision, the electron moves forward and the photon recoils backwards. Calculate the kinetic energy of the electron.

EXIT TICKET (3/10/14)

A 0.045-nm x-ray is scattered through an angle of 30º. What is the frequency of the scattered x-ray?