CPMT Sample Paper Physics

1. In a P-type semiconductor the acceptor impurity level are a
little
(a) below the valance band (b) above the conductor band
(c) above the valence band (d) below the conduction band

2. A bullet fired from a gun has a force on it given by
F=400−8×104 t, such that force becomes zero as soon as the
bullet leaves the barrel of the gun. The impulse imparted to the
bullet
(a) 0.1 NS (b) 2 NS (c) 1 NS (d) zero

3. In a working nuclear reactor, cadmium rods are used to
(a) Absorb all neutrons (b) Absorb some neutrons
(c) Speed up neutrons (d) Slow down neutrons

4. Radius of first orbit of the electron in a hydrogen atom is 0.53Å.
Radius of the third orbit is
(a) 2.12Å (b) 0.18Å (c) 4.77Å (d) 1.06Å

5. Short sight is due to
(a) The eye-ball being too short for the eye lens
(b) A defect in the retina
(c) The eye-ball being too long for the eye lens
(d) A defect in the cornea

6. Mirage is the phenomenon due to
(a) Total internal reflection (b) Interference of light
(c) Polarization of light (d) Diffraction of light

7. Cyclotron is used for accelerating
(a) Protons (b) Lead (c) Atoms (d) Molecules

8. A glass prism of refractive index 1.5 will simply act as a glass
slab when kept in liquid of refractive index
(a) 1 (b) 1.5 (c) 2 (d) √2

9. The dimension of entropy is
(a) M0L−1T0K (b) ML2T−2K−1 (c) M0L−2T0K2 (d) MLT−2K

10. Cathode rays are
(a) A stream of positive charges
(b) A stream of negative charges
(c) A stream of neutral particles
(d) Electromagnetic waves

11. A number of images of a candle flame can be seen in a thick
mirror. The brightest image is:
(a) The last one (b) The first one
(c) The second one (d) The third one

12. At the temperature of inversion, the emf in a thermocouple is
(a) minimum (b) maximum (c) half the maximum value (d) zero

13. Speed of flow of viscous liquid through a capillary tube of
radius r under constant pressure head is proportional to
(a) r (b) r2 (c) r4 (d) r−1

14. A ball hangs from a string inside a train moving along a
horizontal track. The string is observed to incline towards the
front of the train making a small angle with the vertical. It
shows that the train is
(a) Moving with uniform acceleration
(b) Moving with constant retardation
(c) Moving with uniform velocity
(d) At rest

15. The magnetic potential at any point on the equatorial magnet
is
(a) Infinite (b) Zero (c) Positive (d) Finite

16. A potentiometer consists of a wire of length 4m having a
resistance 10Ω. It is connected to a cell of emf 2V. The
potential difference per unit length of the wire will be
(a) 2 V/m (b) 5 V/m (c) 0.5 V/m (d) 10 V/m

17. Speed of the gas ejected from a rocket is 1000ms-1 and the
force experienced as a result is 50 N. The mass of gas escaping
per second is
(a) 5 g (b) 200 g (c) 50 g (d) cannot determined

18. The process in which nuclei join to form a new nucleus and
liberate heat is known as
(a) Fusion (b) Fission (c) Electrolysis (d) Catalysis

19. 540 gm of ice at 00C is mixed with 540 gm of water at 800C.
The final temperature of the mixture in 0C will be
(a) 20 (b) 0 (c) 40 (d) 80

20. When a light is refracted, which of the following does not
change?
(a) Velocity (b) Amplitude (c) Frequency (d) Wavelength

21. A proton has a mass of 1.67×10-27 kg and charge of
1.6×10-19 C. If the proton be accelerated through a potential
difference of one million volts, then the KE is
(a) 1.6×10-13 J (b) 1.6×10-15 J
(c) 1.67×10-13 J (d) 1.67×10-15 J

22. The presence of dissolved impurities in water:
(a) Does not affect its boiling point
(b) Lowers its boiling point
(c) Raises its boiling point
(d) Does not let water boil

23. Natural magnetism of a magnetic material is explained due to
(a) spin of electron
(b) association with earth magnetic field
(c) nucleus
(d) spin and rotation of electron

24. When two turning forks A and B are sounded together four
beats per second are heard. If the frequency of A is 256 Hz,
find that of B. On loading the fork B, the number of beats
decreases.
(a) 252 Hz (b) 264 Hz (c) 248 Hz (d) 260 Hz

25. Two unlike parallel forces P and 2P act at points A and B. Their
resultant acts at a point
(a) A (b) between A and B
(c) on AB produced (d) on BA produced

26. A body of mass m is resting on an inclined plane which makes
an angle θ with the horizontal. As θ increases the normal
reaction of the plane
(a) Decreases (b) Increases (c) Remains unaltered

27. What causes 'Reverberation'?
(a) Reflection (b) Refraction (c) Interference (d) Diffraction

28. On which natural phenomenon is the unit of time based?
(a) Diurnal motion of the earth (b) Rotation of the sun
(c) The revolution of the moon (d) Rotation of the moon

29. A storage cell of emf 10 V and internal resistance 0.1Ω, is
charged with 5 amps. Then the terminal voltage is
(a) 10 V (b) 9.5 V (c) 10.5 V (d) 9.9 V

30. The process of fission, splitting of a heavy nucleus into smaller
nuclei with emission of energy etc, occurs primarily in
(a) The Sun (b) Chemical reactions
(c) Nuclear reactor (d) The hydrogen bomb

31. In the steady state of temperature for a body, the rate of flow
of heat across it depends upon:
(a) Only its thermal conductivity
(b) Only its thermal capacity
(c) Neither on its thermal capacity nor its thermal conductivity
(d) Both its thermal capacity and its thermal conductivity

32. In a series LCR circuit, at resonant frequency
(a) the impedance is maximum
(b) the current and voltage are in phase
(c) current is minimum
(d) the impedance and current are maximum

33. Two conducting spheres of radii 2cm and 4cm are charged.
They are now kept in constant and separated. The ratio of
their potential is
(a) zero (b) 2:1 (c) 1:1 (d) 1:2

34. Compressed air coming out of a punctured ball becomes cooler
because of
(a) isothermal expansion (b) isothermal compression
(c) adiabatic expansion (d) adiabatic compression

35. If the units of length and force be each increased four times,
the units of energy is increased
(a) 16 times (b) 8 times (c) 4 times (d) 32 times

36. A body is perfectly elastic if
(a) It can be easily deformed
(b) It can be easily compressed
(c) It can readily drawn into a wire
(d) It recovers its original shape or volume on the removal of
the deforming forces

37. When a torque acting upon the system is zero. Which of the
following will be constant
(a) Angular momentum (b) Force
(c) Linear momentum (d) Linear impulse

38. Using a convex lens a clear image of a candle flame is produced
on a screen. How many other clear images can be received on
this screen if only the lens is to be shifted?
(a) Two more (b) A large number
(c) Only one more (d) None

39. Energy generation in star is mainly due to
(a) Fission of heavy nuclei (b) Chemical reactions
(c) Fusion of heavy nuclei (d) Fusion of light nuclei

40. The temperature of a gas is produced by:
(a) The kinetic energy of the molecules
(b) The repulsive forces between the molecules
(c) The potential energy of the molecules
(d) The attractive force between the molecules

41. For a heat engine the temperature of the source is 1270C. To
have 60% efficiency the temperature of the sink is
(a) 1130C (b) −1130C (c) −2730C (d) 1600C

42. The equation of a harmonic wave is given by
y = 0.05 sin (2000t − 8x)m. The maximum particle velocity of
the particle in the wave is (in proper units)
(a) 100 (b) 10 (c) 2000 (d) 1000

43. Two capacitors 10 μF and 25 μF are charged to a potential of
100 V each. They are connected in parallel. The potential
across them are
(a) 100 V each (b) 200 V each
(c) 50 V each (d) 80 V and 120 V

44. Two polaroids are kept crossed to each other. Now one of
them is rotated through a angle of 450. The percentage of
incident light now transmitted through the system is
(a) 15% (b) 75% (c) 25% (d) 50%

45. Young's interference experiment is performed with red light of
wavelength 7000Å and the fringes formed at a distance of one
metre has width β. Now red light is replaced by a light of
wavelength 4000Å. In order that the fringes should again have
the same band width β, the screen should be kept at a
distance of
(a) 7/3m (b) 4/7m (c) 7/4m (d) 3/7m

46. For a given kinetic energy the smallest de Broglie wavelength is
for
(a) proton (b) neutron (c) α-particles (d) electron

47. A bimetallic element is a device in which two thin flat strips of
different metals are rivetted together. Such a device can only
be used as:
(a) Thermister (b) Thermionic (c) Thermocouple (d) Thermostat

48. The magnifying power of a Galilean telescope in normal setting
is 15 and its length is 112 cm. The focal length of its eye piece
lens
(a) 16 cm (b) 119 cm (c) 8 cm (d) 105 cm

49. Water has maximum density at
(a) 140C (b) 100C (c) 0.40C (d) 40C

50. A train, 300 m long is traveling with a velocity of 144 km/hr. It
passes over a bridge in 120 seconds. Then the length of the
bridge is
(a) 4.5 km (b) 2.25 km (c) 4.5 m (d) 2.25 m

Answers

1 C 11 C 21 A 31 A 41 B
2 C 12 D 22 C 32 B 42 A
3 B 13 B 23 D 33 C 43 A
4 C 14 B 24 D 34 C 44 C
5 C 15 B 25 C 35 A 45 C
6 A 16 C 26 A 36 D 46 C
7 A 17 C 27 A 37 A 47 D
8 B 18 A 28 A 38 C 48 C
9 B 19 B 29 C 39 D 49 D
10 B 20 C 30 C 40 A 50 A