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SPACE FOR ROUGH WORK

MOCK CET : 2009

(PHYSICS)

1. Which of the following is a derived quantity ?

1) mass 2) velocity 3) length 4) time

2. A body of mass 50 kg acquires a speed of 120 ms under a force of 100N in time

1) 5 s 2) 10 s 3) 15 s 4) 20 s

3. When an object is projected at angle , the horizontal range equals the maximum height reached.The value of must be

1) 1tan 2

2) 1tan 4

3) 1sin 4

4) 1cos 4

4. A long spring is stretched by 2 cm. Its potential energy is U. If the spring is stretched by 10 cm, thepotential energy stored in it will be

1) U/25 2) U/5 3) 5U 4) 25U

5. The spin drier of a washing machine revolving at 900 rpm slows down uniformly to 300 rpm whilemaking 50 revolutions. Its angular acceleration (rev/sec2) is

1) 5 2) 3 3) 2 4) 2.5

6. The distances traveled by a body falling from rest in the first, second and third seconds are in the ratio1) 1 : 2 : 3 2) 1 : 3 : 5 3) 1 : 4 : 9 4) none of these

7. In which of the following pairs of forces, the resultant cannot be 5N ?

1) 2N and 3N 2) 2N and 2N 3) 2N and 7N 4) 5N and 5N

8. Work done in blowing a soap bubble from a radius of 10 cm to 20 cm is (T = 0.025 Nm –1)

1) 36 10 J 2) 3

6 10 J 3) 33 10 J 4) 3

6 / 10 J

9. By What percentage should the pressure of a given mass of gas be increased so as to decrease itsvolume by 10% at a constant temperature

1) 8.1% 2) 9.1% 3) 10.1% 4) 11.1%

10. Two rods A and B having the same cross-section have been joined end to end. Each rod is of thesame length and the ratio of their thermal conductivities is 2 : 1. The left end of A and right end of B arekept at 0°C and 36°C respectively. The temperature at the junction of the rods will be

1) 6°C 2) 12°C 3) 36°C 4) 72°C

11. The temperature of source and sink of a Carnot engine are 327°C and 27°C respectively. The efficiency

of the engine is

1)27

1327

2)

27

3273) 0.5 4) 0.7

Vishwa Bharati Institute, Bangalore 1




12. A simple harmonic oscillator has time period T. The time taken by it to travel from the extreme positionto half the amplitude is

1) T/6 2) T/4 3) T/3 4) T/2

13. An open pipe and a closed pipe of the same fundamental frequency f are joined to form a single closedpipe whose fundamental frequency is

1) 2f 2) f/2 3) f/3 4) 3f

14. Two sounds of intensities 10 1 6 210 and 10watt m watt m respectively have got the same

frequency. These two sounds differ by

1) 110 dB 2) 4

10 dB 3) 4db 4) 40 db

15. The colour of a star is related to its

1) shape 2) size 3) temperature 4) distance from sun

16. If ‘n’ represents the refractive index when a ray of light goes from medium i to medium j, then the

product 2 1 3 2 4 3n n n

1) 3 1n 2) 3 2n 3) 1 41 / n 4) 4 2n

17. The base of a tank is a horizontal glass plate 8 cm thick (n = 1.6). Above this is a layer of liquid of

thickness 4.5 cm (n = 1.5) and upon this floats a layer of water 12 cm thick (n = 4/3). Looking from theabove, the apparent position of the spot on the bottom of the tank is

1) 17 cm 2) 13/3 cm 3) 24.5 cm 4) 31 cm

18. An ink dot on a glass sphere is observed from the side diametrically opposite to it. It appears

1) nearer 2) farther 3) at the same distance 4) on the nearer surface

19. The graph shows the variation of magnification m

produced by a convex lens with the image distance v.

The focal length of the lens is

1) b/c 2) c/b

3) a 4) ab/c

20. The angle of a prism is A and that of minimum deviation is (180° – 2A). Then the refractive index of the

material of the prism is

1) cot4

A

2) tan2

A

3) cot2

A

4) sin2

A

21. Speed of light in vacuum depends on

1) speed of the soruce 2) speed of the observer 3) frequency of light 4) none of these

m

a v

c

b




22. The amplitudes of two interfering light waves are 5 units and 3 units respectively. The ratio of theintensities of bright and dark bands is

1) 5 : 3 2) 3 : 5 3) 1 : 16 4) 16 : 1

23. In Young’s double slit interference experiment, the distance between two sources is 0.1mm. The

distance of the screen from the source is 20 cms. Wavelength of light used is0

5460 A . Then the

angular position of the first dark fringe is

1) 0.08° 2) 0.16° 3) 0.20° 4) 0.32°

24. Diffraction of light takes place with

1) transverse waves only 2) longitudinal waves only

3) both transverse and longitudinal waves 4) neither transverse nor longitudinal waves

25. The aperture of a telescope is 5m. If the separation between the moon and the earth is 54 10 km

and the wavelength of visible light is about 500 nm, the minimum separation between objects on thesurface of the moon which can be just resolved is about

1) 1m 2) 10m 3) 50m 4) 200m

26. A polarizer and an analyzer are oriented so that the amount of light is maximum. When the analyzer isrotated through 30°, the intensity becomes _____________ time the maximum value

1) 0.75 2) 0.50 3) 0.25 4) 0

27. If C is the critical angle for a transparent material and p i is the polarizing angle for its surface, then

1) sin tan p C i 2) sin tanp i C 3) cosec tan p C i 4) sec tan p C i

28. Two charges of 1C and 5C are placed at some distance in air. The ratio of the forces acting on them is

1) 1 : 25 2) 1 : 5 3) 1 : 1 4) 5 : 1

29. The figure shows electric lines of force emerging from a charged body. If the electric fields at point A

and B are AE and B E respectively and the distance

between points A and B is r, then

1) A B E E 2) A B E E

3) A B E E 4) can not be predicted

30. Electric field on the axis of a small electric dipole at a distance r is E1 and E2 at a distance of 2r on aline of perpendicular bisector. Then E2 /E1 =

1) –1/8 2) –1/16 3) –1/4 4) 1/8

31. 64 small drops of water having the same charge and same radius are combined to form one big drop.The ratio of capacitance of big drop to small drop is

1) 4 : 1 2) 2 : 1 3) 1 : 4 4) 1 : 2




32. A parallel plate capacitor with air as medium between the plates has a capacitance of 10 F . The

area of the capacitor is divided into two equal halves and filled with two medium having dielectricconstants 2 and 4 respectively. The modified capacitance is

1) 10 F 2) 20 F 3) 30 F 4) 40 F

33. Two conductors of capacities 3 and 5 units are charged until their potentials are 5 and 7 unitsrespectively. If the two conductors are now connected by a wire, their common potential will be

1) 5.26 2) 6.25 3) 7.34 4) 6.0

34. The colour bands on a resistor are green, blue, orange and silver. The resistance of the resistor is

1) 56 10%k 2) 5.6 20%k 3) 56 20%k 4) 5600 5%k

35. When a resistance of 2 is connected across the terminals of a battery, the current is 0.5A. When

the resistance across the terminals is 5 , the current is 0.25A. The internal resistance of the cell is

1) 0.5 2) 0.75 3) 1 4) 1.5

36. What is the p.d. between A and B shown in the figure ?

1) –9V 2) 21V 3) 9V 4) –21V

37. The magnetic field dB due to a current element at a distant point is

1)

0

24

dl r i dB

r

2) 2

0

24

dl r i dB

r

3)

0

2 24

dl r dB

i r

4)

0

34

dl r i dB

r

38. The magnetic field at a distance r from a long wire carrying current l is 0.4 tesla. The magnetic field ata distance 2r is

1) 0.1 tesla 2) 0.2 tesla 3) 0.8 tesla 4) 1.6 tesla

39. The field normal to the plane of a coil of radius r which carries a current l measured on the axis of thecoil at a small distance h from the centre of the coil is smaler than the field at the centre by a fraction

1)

2

2

3

2

h

r 2)

2

2

2

3

h

r 3)

2

2

3

2

r

h 4)

2

2

2

3

r

h

40. If 90% of the current has to flow through the shunt connected to a galvanometer, the ratio of thegalvanometer resistance to that of the shunt is

1) 4 : 1 2) 9 : 1 3) 8 : 1 4) 2 : 3

41. In electromagnetic induction, the induced charge is independent of

1) change of flux 2) time 3) resistance of the coil 4) none of these

VVVV

6V 9V

A B 3A 3A

2




42. A magnetic field of 22 10 T acts at right angles to a coil of area 2

100 cm with 50 turns. The average

emf induced in the coil is 0.1V, when it is removed from the field in the time t. The value of t is

1) 0.1s 2) 0.01s 3) 1s 4) 10s

43. A 1mH inductance and 10 F capacitance when connected in series to a source, possess equal

reactance. The angular frequency of the a.c. source is

1) 410 2) 100 3) 10 4) 200

44. A step-down transformer is used to reduce 220V supply to 11V. The primary draws 5A of current, whilethe secondary 90A. The efficiency of the transformer is

1) 20% 2) 40% 3) 70% 4) 90%

45. Finger prints on a piece of paper may be detected by sprinkling fluorescent powder on the paper andthe looking it under

1) dark light 2) sun light 3) infra-red light 4) ultraviolet rays

46. The work function of a photo emissive substance is 6.6eV. The longest wavelength of radiation thatcan cause photoelectron emission from the surface of the substace is approximately

1) 220 nm 2) 187 nm 3) 235 nm 4) 400 nm

47. If the kinetic energy of a moving particle is E, then the de-Broglie wavelength is

1) 2h mE 2)2mE

h 3)

2

h

mE 4)

2

hE

mE

48. The atom that participate in ruby laser action are of

1) aluminium 2) chromium 3) oxygen 4) neon

49. If E represents the kinetic energy of an orbital electron and r represents the radius of the orbit, then

1) k E r 2)1

k E r

3)1

k E r

4) 2

1k E

r

50. Hydrogen (H), deuerium (D), singly ionised He and double ionised lithium Li al have one

electron around nucleus. Consider n = 2 to n = 1 transition. The wave lengths of emitted radiations are

1 2 3 4, , and respectively. Then, approximately

1) 1 2 3 44 9 2) 1 2 3 44 2 2

3) 1 2 3 42 2 2 3 2 4) 1 2 3 42 3




51. Which of the following can have a charge q = ne, where n is a fraction and e is the electronic charge.

1) quark 2) sigma 3) tau 4) neutrons

52. A particle moving velocity 1/10th of that light will cross a nucleus in about

1) 810 s 2) 12

10 s 3) v 4) 2010 s

53. Energy released in the fission of a single 235U nucleus is 200MeV. The fission rate of 235U fuelled

reactor operating at a power level of 5W is

1) 10 11.56 10 s 2) 11 11.56 10 s 3) 16 11.56 10 s 4) 17 11.56 10 s 54. Three radioactive substances have their activity in the ratio 1 : 3 : 5. The substances are heated to

double its temperature. Then, the activities will be

1) 5 : 3 : 1 2) 3 : 1 : 5 3) 3 : 5 : 1 4) 1 : 3 : 5

55. In the series of radioactive decay starting from 23490Th and ending on 210

82Pb the number of and

particles emitted are

1) 3, 3 2) 6, 4 3) 6, 0 4) 4, 6

56. In a transistor, the emitter current E I , collector current C I and base current B I are related by

1) E B C I I I 2) C E B I I I 3) B C E I I I 4) C B E I I I

57. The collector supply in a common emitter amplifier is 8 volts and the voltage drop across the load of

800 is 0.4V. If 0.96 , then what is the base current ?

1) 20 A 2) 21 A 3) 22 A 4) 24 A

58. Decimal number 53 is equal to binary number

1) 11 11 11 2) 10 10 10 3) 10 11 10 4) 11 01 01

59. The ratio of the ac component to the dc component in the output voltage of a rectifier is called

1) current gain 2) voltage gain 3) amplification factor 4) ripple factor

60. In Davission - Germer experiment, the nickel crystal behaves like a

1) three dimensional diffraction grating 2) metallic foil

3) absorption plane 4) an emission plane

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