SMJK Katholik Trial STPM 2010 Physics

CATHOLIC HTGH SCHOOL, P.J.2O1O STPM TRIAL EXAMINATION

PHYSTCS PAPER I (960/1)(One hour and forty-five minutes)

Prepared by Mdm SIM CNInstructions to cahdidates :' Theil are fifty question.s in this paper. For each questfun, four sugg;ested answers are given. Choose one correctanswer and indicate it on the multiple- choice answer sheet provided.

Answer all questions. Marks will not he deductedfor wrong awwers.A Data Booklet is provided.

I . A coil has a large inductance, l, . A change of curent in it will induce a large back e.m.f. , e . The equation relatingthe inductance of the coil to the induced back e.m.f. and the rate of change of cument[is

dtL_

*_

dt_dt

-fhe SI base unit for L isA ke m2 s-2 A-lC k!m2 5-2 4-z

B kg m's-r A-2C kg m s-2 A-t

2. A hot air balloon loaded with stones is accelerating downwards with a constant acceleration of % g, where g is theacceleration due to gravity. If the total mass of the balloon is M, what mass of the stones must be removed in order thatth'e balloon now accelerates upwards with t/4 s. ?A I/3 M B 213 M C2/5 M D 3/5 M

3. A projectile is fired with an initial speed of 5 1.2 m s-r at a4 angle of 44.5o above the horizontal on a long flat firingrange. Point A is the maximum height attained by the projectile. What is the vertical component of the speed and thelocation of the projectile t.50 s after firing ?

Speed / m s-tA 2t .2B 2t .2c . 35.6D 35.6

A uniform horizontal beam of length L and weightfigure below. A boy weighing 500 N stands t/5 L

200 N231 N563 N808 N

LocationBefore point AAfter point ABefore point AAfter point A

4. A helicopter of mass 5.0 x l0r kg rises vertically with a constant speed of 25 m s-t. The upward resultant force actingthe helicopter is

ON B 4.9x104N C 9.8x104 N D 2.6 x l05N

AonA

ABCD

5. is attached to the wall by means of a cable as shown in thefrom the wall. The tension in the cable is

%%%beam%kJ of energy to accelerate uniformly from rest to a final speed of v. The power output of the car'smaximum value of 100 kw at speed v. l{ow long does it take by the car to reach v ?

200 Naway

B 10.0 s C 15.0 s D 20.0 s

is built at the equator on a hill of height 2.5 km. As a result of the Earth's rotation , what is, in m s-', between a marl at the top of the tower and someone at sea revel

c 5.20

6. A car consumes 500engine increases to aA 5.00 s

7. A radar tower 0.50 km tallthe difference in the speedA zero B 0.22

-t-

D 19.0

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8. Two satellites P and Q are in the same circular orbit round the Earth. The mass of P is greater than the mass of Q.Which of the following quantities is NOT greater in magnitude for P than fbr Q ?

1.0

2rJ

A

r0. AE1

ABCD

9. A satellite skims the Moon's surface in a circular orbit. The acceleration at the Moon's surface due to gravity is g/fuandthe Moon's radius is R/4 , where g is the acceleration due to gravity on the surface of the Earth and R is the radius of theEarth. If a satellite, skimming the Earth's surface, has a period T, the period of revolution of the Moon's satellite will be

B{( ?J--)aJ

c QB)27 D \(3/2)r

particle of mass 90.0 g undergoes simple harmonic motion. The graph below shows the variation of its kinetic energy,with time , t . What is the maximum acceleration , in ffi s-2 , of the particleEx/ 'l

0.0740.3737.074.0

I L A conical pendulum undergoes uniform circular motion in a horizontal plane. The radius of the circular path is 50.0 cmand the time taken to complete one revolution is 2.16 s. A lamp shines on the pendulum bob as shown below.The shadow of the bob on the screen was observed to move back and forth along a horizontal line with

A angular velocityC potential energl

B kinetic energyD gravitational force

c 1.048

A constant speed of 1.45 m s''.B constant speed of 4.23 m s-'.C speed varying between 0 and 1.45 m s'r.D speed varying between 0 and 4.23 m s-'. F't .

-J lamp

B Maxirnum positiveD Half the maximum positive

Iscreen

12.

13.

14.

Astat ionarywave inastretchedstr ingisrepresentedbytheequat ion y=6sinr r cos( l0n)t where.randyare4

are measured in cm and t is measured in s. T'he distance between two consecutive antinodes in the stationary wave isA 2.0 cm B 4.0 cm C 6.0 cm D 8.0 cm

A sound wave is represented as follows;P - posin( l00rt - l r ; r )

where p is the change in pressure of the air from the normal atmospheric pressure. The displacernent of the air moleculesat a point where p has a maximum negative value is

A Maximum negativeC Zero

A point source of sound emits 20 W of power unifomrly in all directions. The intensity and intensity level of the soundatadistanceof 5.0mfromthesoundare ( lntensi tyat thethresholdof hear ing : l .0x l0-r2 W*-t)

Intensity/ Wm-' Intensit-v_levelftlBA 4.7 x l0'2 87B 6.4 x l0 '2 108C 6.4 x l0-2 216D 0.47 95

A man in a car moving at a constant speed of l5 m s-l approaches and then leaves a sound source. If the speed of soundin air is 330 m s'' and the apparent frequencies of the sound heard by the man arefl and.f2 respectively.The ratio of f1 lf2 is

A r .000 B t .045

15.

D 1.095


16. 'the graph below shows how the potential energ1l ,U, changes with the separationbetween atoms ,r, for two Upes of.solids A and B. Which of the following statements is true ? L{

A Atoms in solid B are further apart.B Solid A is more elastic than solid B.C Molar latent heat of fusion of B is greater.D Young's modulus of solid A is bigger.

R

17. A cable which is 40 m long has a cross-sectional area of 0.0085 m,. The tension in the oable is 750 kN .lf the Young'sModulus of the cable is 2.8 x l0rr Pa, The strain energy stored in the cable is

A 2189 J B 2774 I c 3532 J D 4730 l

18. The mass of an oxygen molecule is l6 times that of a hydrogen molecule. At room temperature, the ratiomean translational kinetic energy of an oxygen rnoleculemean translational kinetic energy of a hydrogen molecule

isCI D 0.0625

, V1) to (pr, Vr) by either process (i) or process (ii) .A system ofideal gas undergoes a change ofstate from (p1Which of the following statements is correct ?

A The work done by the gas is greater in (i) than in (ii).B The change in internal energy of the system in both

processes are the same.

(pvY)

C The heat supplied tothe gas is greater (i) than in (ii)D If (i) is such that pV is kept constant, it is an adiabatic

process.(pr'vr)

20. The root-mean-square speed of a molecule of an ideal gas at pressure P and volume V is c. The gas is heated so thatits volume expands to (312) V and its pressure becomes 3P. The new root-mean-square speed of the gas molecules is

A 2. lc B 3.4c C 4.7c D 4.9c

Bl6A

19.

p

2 | -

50 J of heat enerry is required to increase the temperature of I mole of a diatomic gas by loC at constant volume. Themolar heat capacity of the gas at constant pressure , Co, in J mol-r K-1, is

A23 B4l c65 D70

22. "I'wo uniform cylindrical metal rods A and B of equal length have diameter in the ratio of 1 : 2 and they have the sametemperature difference between their ends. If the thermal conductivities of A and B are in the ratio of I : 2 , the ratiorate of heat conduction in A israte if heat conduction in B

D 2: l

23. Four charges of equal magnitude are placed at the four corners of a square as shown below. If the net electric field at thecentre-of the square , O , is directed towards Q , which of the follcrwing statements about the signs of the four charges istrue ?

I

AiBciD.

Pi2rn s

i-+

F

+

+

T

p

Q, i

-3-

J---------- - . - - . \J_l)H


24. N small drops of the same size are charged to V volts each. If they coalesce to form a single large drop, then its potentialwi l lbe

A V/N BVN

25. A proton moves from P to Q under the influence of an electric field. The path taken is traced out on a diagram markingout equipotential lines as shown ( diagram not drawn to scale)If the kinetic energy of the proton at P is 7.5 x l0-r7 J, what is its kinetic energy at Q ?

.,,

A 2.7 x l0't7 JB 4.3 x l0 ' r7 JC 7.5 x l0-r7 JD l . l x l0-r8J

26. The figure below shows a potentiometer circuit.'fhe driver cell has an e.m.f. of 2.00 V and negligible internal resistance.AB is a resistance wire of length 1.000 m. The e.m.f. of the cell is 0.800 V and the balance leneth AX is 0.640 m.The ratio rgrb@rcg !fthc_uusrlB_ is

Resistance of R

0.3750.600r.500t.670

cell27. The diagram below showsaresistormadeof acoppercylindricalcoreof cross-sectional area2.0 x l0-3 m2which is

surrounded by iron of cross-sectional area 1.0 x l0-3 rn2 .Given that copper and iron have resistivities of | .7 x l0-8 Clrn and 1.0 x l0-i Qm respectively. The resisknce perunit length of such a resistor , in C)m-l , is

A 7.8x 10"B 8.5 x 10-6C 1.5 x l0-5D 3.9 x l0-5

28. A current I flows in a wire of circular cross-section with the free electrons travelling with a drift velocity v . What is thedrift velocity of electrons when a current of 2l flows in another wire of twice the radius and of the same material ?Av B2v C v/2 D vl4

29. The capacitance of a capacitor filled with two dielectrics of the same dimensions but of dietectric constants k1 and k2respectively is proportional to

A kr + k: B krkz_kr+kz

30. A charged particle is projected at right angles into a magnetic field as shown below.Which of the followins is correct ?

ABCD

c v(N)"t

CIkr+kz

D v(N)"'

t) __t

_

kr kz

A The Momentum of the particle is increasing steadily.B 'Ihe magnetic flux density is decreasing steadily.C The speed of the particle is decreasing steadily.D The charge of the particle is decreasing steadily.

-4-

Region of uniformmagnetic field intothe paper


31. Two parallel conductors carry sinusoidal alternating currents that differ in phase by n radians 'The diagram on the right shows the flow of current at a particular instant.Which of the following graphs shows a possible variation of the force ,F, with respect to time, t,experienced by one ofthe conductors ?

32. The average power dissipated in a resistor of resistance R supplied with an alternating current of peak value Io is P.For a resistor 2R to dissipate an average power of 4P when supplied rvith another alternating cttrrent, the new root-mean-square must beAb_ Bro

nt lt llt li l llil riJ

ntlt ltiill

, l l ltlU

33. The diagram below shows a wire carrying a current t. A straight conductor PQ is placed on the same vertical plane as thewire and is moved at constant speed v away from the wire. FIow will the magnitude of the induced e.m.f. in PQ vary and

decreasesdecreasesincreasesincreases

C t"./2 D 2lo

e 's variation with time ?

T2T3I

which end will be at a higher potential ?magnitude of induced-q.lul end at higher potential ]l*'

PQRS in an uniform magnetic field. The magnetic flux density B changes

ABcD

PaPa

34. The figure (a ) shows a rectangular wire coilwith time t as shown in figure (b).

""[aJ,.XXX

(a)

Which of the following graphs best represents the induced e.m.f.

At C

l!

t !

2T 3T

D

t!

1_-7ffi--+,

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35. A cunent of 5.0 A passing through a coil produces a magnetic flux linkage of 2.0 x l0{ Wb through the coil. Whenthe switch is opened, the current drops to zero in 0.04 s , the mean e.m.f. induced in the coil isA 5.0 mA B 7.8 mA C 26mA D 103 mA

36. An operational amplifier circuit is shown in the figure below.The output voltage Vowhen Vr = 0.5 V is

0.5 v5.0 v5.5 V0.505 v

37. What is the source of electromagnetic wave ?A An accelerating particle.B A charged particle moving with constant speed.

C An accelerating charged particle.D A constant current.

38. A glass lens with refractive index 1.50 has a convex surface of radius of curvature 2.0 m and a second concave surfacewith radius of curvature of 1.0 m . The f

44. If 1," is the de Broglie wavelength of an electron accelerated from rest through a potential difference of l0 V and ),1 isthat of an electron accelerated frorn rest through a potentialdiffererrce of 1000 V . The value of the ratio l* / l,r is

A0.r0 B l c l0 D 100

45. When the maximum speed of the incident elestrons in a certain X-ray tube is v, the minimum wavelength produced is\o . The maximum speed of the incident electrons if the minimum wavelength of the X-rays produced is reduced to( l/16) 1", is

A l6v B 8v C 4v D2v

46. A simple model of energy levels in an atom has only three levels X, Y and Z. A transition from level X to level Zproduces radiation of wavelength 400 nm ; a transition from level Y to level Z produces a radiation of wavelength700 nm. Which of the following deductions made by the student about the energy level scheme is correct ?

A The wavelength of radiation emitted in a transition from levels X to Y is 300 nm.B The wavelength of radiation absorbed in a transition from levels X to Y is 300 nm.C Level Y has a greater energy than levels X and Z,D Level X has a greater enerry than levels Y and Z.

47. The concentration of tfC atoms in an ancient fabric was found to correspond to a decay rate of 9.2 min't per gramof carbon. It was knowi that rfC atoms in living plants decay at the rate of 70.0 min-r for 5 grams of carbon. Whatis the age of the fabric , given that the half-life of 'lC is 5730 years ?

A 3.47 x 103 years C 5.01 x 103 yearsB 1.68 x lOa years D 2.42 x lOa years

48. A radioactive nuclide emits an a-particle and two B-particles. Compared with the original nuclide, the resulting nuclidewill have

A the same nucleon number.B a higher proton number.C a lower proton number.D the same proton number.

49. Given that the energy released from the fission of Uranium-235 is 200 MeV, what is the number of fission per secondthat must occur in a nuclear power station which uses the fission of tJ-235 to produce output power of I .0 MW ?

A 5.0x103 B l .4xl0 '2 c 5.6xl0ra D 3. lx l0t6

50. Which of the following is true about neutrino ?A It is an antiparticle of neutron.B lt has the same mass as electron.C It is made up of quarks.D It is emitted together with a beta-particle.


SECTION B [60 marks]Answer any four questions in this section .

9. (a) Explainwhatismeantby (D tarque, and (ii) momentof inertia.(b) The diagram below shows a flywheel which is set into motion by applying a force of 20 N to a length of cord wrapped

around the axle which has a radius of 0.015 m. The force is at right angles to the axis of rotation, and the cord becomesdetached after the force has been applied for 5.0 s. The moment of inertia of the system about the axis of rotation is0.050 kg m2 ,and the frictional torque opposing the motion is constant at 0.05 N m.

flywheel

20N

(i) Calculate the torque provided by the 20 N force, and deduce the angular acceleration of the flywheel. t3I(ii) Calculate the maximum angular velocity ofthe flywheel. I2l(iii) At the moment when the cord becomes detached, a body is dropped from a small height and sticks to the

flywheel. The effect is to increase the moment of inertia of the system to 0.075 kg m' 'L Describe and explain how the angular velocity of the flywheel is affected immediately after the impact . t3l2. Assuming that the frictional torque is unchanged, explain whether the presence of extra mass will affect the time

t4l

taken for the flywheel to come to rest.

10. (a) (i) What is meant by the degree offreedom of a gas molecule ?

(b) State the law of equipartition of energt .

(c) A containerof volume 2.0 x l0-3 m3 contains 8.0 gof heliurn gas at pressure 1.01 x 105 Pa. Determine(i) the internal energ/ of the gas,(ii) the mean kinetic energy of one molecule of helium gas .

(d)t?lI2l

l2lt2lr2ltzl

p r to&pa

2,Lz"o

0.6,, ,n 3J

ln a diesel engine, the working substance is 3.0 moles of an ideal monoatomic gas. The gas undergoes a cycle ofthermodynamic processes ABCDA as it drives the engine.(i) Determine the thermodynamic temperature of the gas at B.(ii) Determine the change in the intemal enerry of the gas in process BC.(iii) Determine the work done by the gas in process BC.(iv) Determine the heat absorbed by the gas in process BC .

13ll l l

tzl

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11.(a) (i) whatismeantbythe capacitanceofapctrallel-platecapacitor ? l2l(ii) Two parallel-plate capacitors, P and Q, have the same dimensions, but are filled with different dielectrig

Materials wittr dielectric constants, Kp and Kq respectively. If the capacitance of P is 4 times that of Q,determine the ratio of the dielectric constants K p / Kq. I2l

(b) A parallel-plate capacitor is constructed from two flat square metal plates, each of dimensions 0.20 m x 0.20 mseparated a 2.0 mm thick polythene sheet which completely fills the space between the plates. The capacitor isconnected in the circuit shown. The switch S vibrates so that so that the capacitor is completely charged anddischarged 200 times per second through a microammeter of negligible resistance. When the supply has an e.m.f.of 100 V the meter shows a steady reading of 8.0 pA.

Calculate(i) the charge fansferred to the capaoitor during each charging process'(ii) the capacitance of the capacitor ;(iii) the relative permittivity of polythene.' ' ( perrnittivity of free .puc" = il.g x 10-t2 F m-t )

l2lt2lt21

(c) The experiment described in (b) is repeated but with a 100 kCl resistor connected in series with the microammeter.(i) Describe the effect, if any, of including this resistor in the charging and discharging of the capacitor. t3](ii) Calculate the time constant of the discharge circuit and state whether the resistor will affect the micrometer

reading. Explain your answer carefully. tzl

l2l12. (a) Explain the term Hall ffict(b) Fig. 1 shows a rectangular slice of n- type semiconductor which is connected to a battery so that the current flows

from left to'right "t

r[o*n. The current is due to electrons of charge -e moving with speed v . A uniform magneticfield of flux density B acts vertically downwards through the plane of the slice-

(i) Write down an equation for the force on an electron in the slice due to the Hall voltage. l2l(ii) State the polarity of the Hall voltage in the slice. tU(iii) Describe and explain the effect on the value of the l{all voltage of first increasing the current in the slice and

then replacing the semiconductor slice by a copper slice of the same dimensions and carrying the same currntas originally. t4l

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12. (cflhe Hall effect can be used to measure the rate of flow of an ionized liquid through a pipe. Fig. 2 shows the principleof the method. An electromagnet produces a magnetic field vertically downwards perpendicular to the direction of

-

flow,and the Hall effect is measured.

flow

(i) Explain why Hall voltage is produced in this case. L?l(ii) ln an experiment, an ionized liquid is flowing at a ^ rate of 9.0 x | 06 m3 s-r through a plastic pipe of diameter7.5mm. A magnetic field of flux density 8.0 x 10-' T acts at right angles to the flow.Calculate the average speed of the flow of the liquid and determine the potential difference which is developedacross the elechodes , assuming them to be 7.5 mm apart. t4I

13. (a) Explain the meaning of the following terms in relation to the production of a laser beam :-(i'1 stimulated emics ion(ii) populuion inversioTt

(b) The table below shows some typical characteristics of a He-Ne gas laser.

tzltzl

Waveleneth Beam diameter at laser exit Beam intensitv at laser exit633 nm 0.50 mm 5100 mW cm

(D From the data given, determine the enerry of each photon in the laser beam in eV. t21(ii) Hence determine the rate of emission of photons from the laser exit. IzJ(iii) Calculate the momentum of each photon. tll(c ) In the figure below, X and Y are two navigation hansmitters 100 km apart emitting radio waves of frequency

341 l,*lz. The signals are of the sarne amf'litude and they,are emitted in phasrl.l.n aircraft is moving along theline joining the transmitters and it receives signals from each transmitter.

.Fh-_-f -#

(i) Point M is mid-way between X and Y while N is | 100 m away from M. Explain clearly whether the signalsfrom the two transmitters interfere constructively or desffuctivelvl. atpointM, and2. atpointN. t4l(ii) Sketch a graph to show the variation of the amplitude of the resultant wave with distance as the aircraft movesfrom M to N. t2J

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la. (a) A radioactive isotope of thallium,t|, ,t , emits beta particles (B-) with an average enersi of 1.5 MeV. fn" t-utf-nfe ofthe radioisotope is 135 days , and it is also thought to emit gamma radiation.

(i) What is meant by a half-life of 135 days? tll(ii) Calculate the total energy, in joules, available from the beta particles emiffed from 1.0 g of the isotope . 12)(iii) Determine the initial rate at which beta particles are emitted from 1.0 g of the freshly prepared isotope t21(iv) Determine, the initial power, in watts, available from the beta particles emitted at the rate calculated in (iii). t2]

(c)

A particular medical application requires a sample of radioisotopes with a rate of decay of 3.90 x 103 s-l at thetime of application. If the selected radioisotope has a half-life of 2.0 days and is prepared one week before theapplication begins, calculate(i) the rate of decay of the radioisotope at the time of preparation,(ii) the number of the particles emitted if the radioisotope is used for 30 minutes at each application.

Iron- 54, ta Fe has an atomic mass of 53.9396 u.26

(i) Define binding energ/ of a nucleus .(ii) Determine the binding energy of lron-54 nucleus.(iii) Determine the binding enerry per nucleon of the lron-54 nucleus.

( mass of proton = 1.007276 uMassof neutron = 1.008665 u )

(b)

121I2l

t l ltzlIU

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SMJK Katholik Trial STPM 2010 Physics

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