## PHYSICS- PAGE 8

## NEET UG 2017 PHYSICS QUESTIONS AND ANSWERS

1. A spring of force constant k is cut into lengths of ratio 1 : 2 : 3 . They are connected in series and the new force constant is k '. Then they are connected in parallel and force constant is k" . Then k': k " is : -

(1) 1 : 9

(2) 1 : 11

(3) 1 : 14

(4) 1 : 16

Ans: 2

2. The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz . What is the fundamental frequency of the system?

(1) 20 Hz

(2) 30 Hz

(3) 40 Hz

(4) 10 Hz

Ans: 1

3. A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :-

(1) Decreases by a factor of 2

(2) Remains the same

(3) Increases by a factor of 2

(4) Increases by a factor of 4

Ans: 1

4. Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8 th bright fringe in the medium lies where 5 th dark fringe lies in air. The refractive index of the medium is nearly:-

(1) 1.59

(2) 1.69

(3) 1.78

(4) 1.25

Ans: 3

5. Tow cars moving in opposite directions approach each other with speed of 22 / m s and 16.5 / m s respectively. The driver of the first car blows a horn having a a frequency 400 Hz . The frequency heard by the driver of the second car is [velocity of sound 340 / m s ] :-

(1) 361 Hz

(2) 411 Hz

(3) 448 Hz

(4) 350 Hz

Ans: 3

6. A thin prism having refracting angle 10° is made of glass of refractive index 1.42 . This prism is combined with another thin prism of glass of refractive index 1.7 . This combination produces dispersion without deviation. The refracting angle of second prism should be :-

(1) 6°

(2) 8°

(3) 10°

(4) 4°

Ans: 1

7. The acceleration due to gravity at a height 1 km above the earth is the same as at a depth d below the surface of earth. Then :-

(1) d =1 km

(2) d=3/2 km

(3) d =2 km

(4) d=1/2 km

Ans: 3

8. A potentiometer is an accurate and versatile device to make electrical measurements of E M F because the method involves :-

(1) Potential gradients

(2) A condition of no current flow through the galvanometer

(3) A combination of cells, galvanometer and resistances

(4) Cells

Ans: 2

9. A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K . If the radius were halved and the temperature doubled, the power radiated in watt would be :-

(1) 450

(2) 1000

(3) 1800

(4) 225

Ans: 3

10. Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will :-

(1) Move towards each other.

(2) Move away from each other.

(3) Will become stationary

(4) Keep floating at the same distance between them.

Ans: 1

11. The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is :-

(1) 1

(2) 4

(3) 0.5

(4) 2

Ans: 2

12. A carnot engine having an efficiency of 1/ 10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J , the amount of energy absorbed from the reservoir at lower temperature is :-

(1) 90 J

(2) 99 J

(3) 100 J

(4) 1 J

Ans: 1

13. A gas mixture consists of 2 moles of Oxygen O2 and 4 moles of Ar at temperature T . Neglecting all vibrational modes, the total internal energy of the system is :-

(1) 15 RT

(2) 9 RT

(3) 11 RT

(4) 4 RT

Ans: 3

14. Which of the following statements are correct?

(a) Centre of mass of a body always coincides with the centre of gravity of the body

(b) Central of mass of a body is the point at which the total gravitational torque on the body is zero

(c) A couple on a body produce both translational and rotation motion in a body

(d) Mechanical advantage greater than one means that small effort can be used to lift a large load

(1) (a) and (b)

(2) (b) and (c)

(3) (c) and (d)

(4) (b) and (d)

Ans: 4

15:-Of the two bulbs in a house, one glow brighter than the other. Which of two has the higher resistance?

A:-The bright bulb

B:-The dim bulb

C:-Both have same resistance

D:-Brightness does not depends upon the resistance

Ans: B

16:-In nuclear reactor, cadmium rods are used to control the reaction. Because

A:-it slow down reaction

B:-it absorbs neutrons

C:-it emits neutrons

D:-it neutralizes the reactor materials

Ans: B

17:-The color of thin film is due to

A:-interference

B:-diffraction of light

C:-reflection of light

D:-refraction of light

Ans: A

18:-The geo stationery satellite are moving from

A:-east to west

B:-north to south

C:-west to east

D:-south to north

Ans: C

19:-When a wave travels from one medium to another medium, which of the following quantity remains the same?

A:-Frequency

B:-Wavelength

C:-Velocity

D:-Intensity

Ans: D

20. The motion of an iron ball falling down under the action of gravity near the surface of the earth is :

(A) uniform velocity (B) uniform acceleration

(C) non-uniform acceleration (D) uniform retardation

Ans: B

21. Two object are said to have perfectly elastic collision when, before and after collision, their :

(A) momentum and kinetic energy are conserved

(B) momentum is conserved and kinetic energy is not conserved

(C) momentum is not conserved and kinetic energy is conserved

(D) momentum and kinetic energy are not conserved

Ans: A

22. The process involved in the sudden bursting of cycle tyre is :

(A) isochoric process (B) isothermal process

(C) adiabatic process (D) isobaric process

Ans: C

23. The temperature at which the reading on the Celsius scale of temperature and Fahrenheit scale of temperature becomes equal :

(A) − 30 degree (B) − 20 degree (C) − 50 degree (D) − 40 degree

Ans: D

24. Fundamental equation that relates fluid pressure, fluid velocity and fluid height is :

(A) Equation of continuity (B) Bernoulli’s theorem

(C) Stoke’s law (D) Archimede’s principle

Ans: B

25. The resistance of a conductor depends on :

(A) length of the conductor

(B) area of cross-section of the conductor

(C) material of the conductor

(D) all of the above

Ans: D

26. The vibrant colours seen on the surface of thin oil films on the surface of water is due to :

(A) interference of light (B) refraction of light

(C) dispersion of light (D) scattering of light

Ans: A

27 An example of universal gate is :

(A) NOT gate (B) AND gate (C) OR gate (D) NOR gate

Ans: D

28. The increasing order of frequency of electromagnetic wave is :

(A) X-ray, gamma ray, radio wave, micro wave

(B) gamma ray, radio wave, X-ray, micro wave

(C) radio wave, micro wave, X-ray, gamma ray

(D) micro wave, gamma ray, radio wave, X-ray

Ans: C

29. When a double convex lens with refractive index 1.5, is immersed in a solution of Carbon disulphide with refractive index 1.62, the focal length of this lens becomes ?

(A) more positive (B) negative

(C) zero (D) infinite

Ans: B

(1) 1 : 9

(2) 1 : 11

(3) 1 : 14

(4) 1 : 16

Ans: 2

2. The two nearest harmonics of a tube closed at one end and open at other end are 220 Hz and 260 Hz . What is the fundamental frequency of the system?

(1) 20 Hz

(2) 30 Hz

(3) 40 Hz

(4) 10 Hz

Ans: 1

3. A capacitor is charged by a battery. The battery is removed and another identical uncharged capacitor is connected in parallel. The total electrostatic energy of resulting system :-

(1) Decreases by a factor of 2

(2) Remains the same

(3) Increases by a factor of 2

(4) Increases by a factor of 4

Ans: 1

4. Young's double slit experiment is first performed in air and then in a medium other than air. It is found that 8 th bright fringe in the medium lies where 5 th dark fringe lies in air. The refractive index of the medium is nearly:-

(1) 1.59

(2) 1.69

(3) 1.78

(4) 1.25

Ans: 3

5. Tow cars moving in opposite directions approach each other with speed of 22 / m s and 16.5 / m s respectively. The driver of the first car blows a horn having a a frequency 400 Hz . The frequency heard by the driver of the second car is [velocity of sound 340 / m s ] :-

(1) 361 Hz

(2) 411 Hz

(3) 448 Hz

(4) 350 Hz

Ans: 3

6. A thin prism having refracting angle 10° is made of glass of refractive index 1.42 . This prism is combined with another thin prism of glass of refractive index 1.7 . This combination produces dispersion without deviation. The refracting angle of second prism should be :-

(1) 6°

(2) 8°

(3) 10°

(4) 4°

Ans: 1

7. The acceleration due to gravity at a height 1 km above the earth is the same as at a depth d below the surface of earth. Then :-

(1) d =1 km

(2) d=3/2 km

(3) d =2 km

(4) d=1/2 km

Ans: 3

8. A potentiometer is an accurate and versatile device to make electrical measurements of E M F because the method involves :-

(1) Potential gradients

(2) A condition of no current flow through the galvanometer

(3) A combination of cells, galvanometer and resistances

(4) Cells

Ans: 2

9. A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K . If the radius were halved and the temperature doubled, the power radiated in watt would be :-

(1) 450

(2) 1000

(3) 1800

(4) 225

Ans: 3

10. Two astronauts are floating in gravitational free space after having lost contact with their spaceship. The two will :-

(1) Move towards each other.

(2) Move away from each other.

(3) Will become stationary

(4) Keep floating at the same distance between them.

Ans: 1

11. The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is :-

(1) 1

(2) 4

(3) 0.5

(4) 2

Ans: 2

12. A carnot engine having an efficiency of 1/ 10 as heat engine, is used as a refrigerator. If the work done on the system is 10 J , the amount of energy absorbed from the reservoir at lower temperature is :-

(1) 90 J

(2) 99 J

(3) 100 J

(4) 1 J

Ans: 1

13. A gas mixture consists of 2 moles of Oxygen O2 and 4 moles of Ar at temperature T . Neglecting all vibrational modes, the total internal energy of the system is :-

(1) 15 RT

(2) 9 RT

(3) 11 RT

(4) 4 RT

Ans: 3

14. Which of the following statements are correct?

(a) Centre of mass of a body always coincides with the centre of gravity of the body

(b) Central of mass of a body is the point at which the total gravitational torque on the body is zero

(c) A couple on a body produce both translational and rotation motion in a body

(d) Mechanical advantage greater than one means that small effort can be used to lift a large load

(1) (a) and (b)

(2) (b) and (c)

(3) (c) and (d)

(4) (b) and (d)

Ans: 4

15:-Of the two bulbs in a house, one glow brighter than the other. Which of two has the higher resistance?

A:-The bright bulb

B:-The dim bulb

C:-Both have same resistance

D:-Brightness does not depends upon the resistance

Ans: B

16:-In nuclear reactor, cadmium rods are used to control the reaction. Because

A:-it slow down reaction

B:-it absorbs neutrons

C:-it emits neutrons

D:-it neutralizes the reactor materials

Ans: B

17:-The color of thin film is due to

A:-interference

B:-diffraction of light

C:-reflection of light

D:-refraction of light

Ans: A

18:-The geo stationery satellite are moving from

A:-east to west

B:-north to south

C:-west to east

D:-south to north

Ans: C

19:-When a wave travels from one medium to another medium, which of the following quantity remains the same?

A:-Frequency

B:-Wavelength

C:-Velocity

D:-Intensity

Ans: D

20. The motion of an iron ball falling down under the action of gravity near the surface of the earth is :

(A) uniform velocity (B) uniform acceleration

(C) non-uniform acceleration (D) uniform retardation

Ans: B

21. Two object are said to have perfectly elastic collision when, before and after collision, their :

(A) momentum and kinetic energy are conserved

(B) momentum is conserved and kinetic energy is not conserved

(C) momentum is not conserved and kinetic energy is conserved

(D) momentum and kinetic energy are not conserved

Ans: A

22. The process involved in the sudden bursting of cycle tyre is :

(A) isochoric process (B) isothermal process

(C) adiabatic process (D) isobaric process

Ans: C

23. The temperature at which the reading on the Celsius scale of temperature and Fahrenheit scale of temperature becomes equal :

(A) − 30 degree (B) − 20 degree (C) − 50 degree (D) − 40 degree

Ans: D

24. Fundamental equation that relates fluid pressure, fluid velocity and fluid height is :

(A) Equation of continuity (B) Bernoulli’s theorem

(C) Stoke’s law (D) Archimede’s principle

Ans: B

25. The resistance of a conductor depends on :

(A) length of the conductor

(B) area of cross-section of the conductor

(C) material of the conductor

(D) all of the above

Ans: D

26. The vibrant colours seen on the surface of thin oil films on the surface of water is due to :

(A) interference of light (B) refraction of light

(C) dispersion of light (D) scattering of light

Ans: A

27 An example of universal gate is :

(A) NOT gate (B) AND gate (C) OR gate (D) NOR gate

Ans: D

28. The increasing order of frequency of electromagnetic wave is :

(A) X-ray, gamma ray, radio wave, micro wave

(B) gamma ray, radio wave, X-ray, micro wave

(C) radio wave, micro wave, X-ray, gamma ray

(D) micro wave, gamma ray, radio wave, X-ray

Ans: C

29. When a double convex lens with refractive index 1.5, is immersed in a solution of Carbon disulphide with refractive index 1.62, the focal length of this lens becomes ?

(A) more positive (B) negative

(C) zero (D) infinite

Ans: B

30. Which of the following transitions is NOT allowed in the case of an atom, according to the electric dipole radiation selection rule?

(A) 2s-1s

(B) 2p-1s

(C) 2p-2s

(D) 3d-2p

Ans: A

31.The scattering of particles by a potential can be analyzed by Born approximation. In particular, if the scattered wave is replaced by an appropriate plane wave, the corresponding Born approximation is known as the first Born approximation. Such an approximation is valid for

(A) large incident energies and weak scattering potentials.

(B) large incident energies and strong scattering potentials.

(C) small incident energies and weak scattering potentials.

(D) small incident energies and strong scattering potentials.

Ans: A

(A) 2s-1s

(B) 2p-1s

(C) 2p-2s

(D) 3d-2p

Ans: A

31.The scattering of particles by a potential can be analyzed by Born approximation. In particular, if the scattered wave is replaced by an appropriate plane wave, the corresponding Born approximation is known as the first Born approximation. Such an approximation is valid for

(A) large incident energies and weak scattering potentials.

(B) large incident energies and strong scattering potentials.

(C) small incident energies and weak scattering potentials.

(D) small incident energies and strong scattering potentials.

Ans: A

32. Which one of the following equations of motion represents simple harmonic motion? Where k, k0, k1 and a are all positive.

1) acceleration = - k(x + a)

2) acceleration = k(x + a)

3) acceleration = kx

4) acceleration = - k0x + k1x2

Ans: 1

33. If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is:

1) repelled by the north pole and attracted by the south pole

2) attracted by the north pole and repelled by the south pole

3) attracted by both the poles

4) repelled by both the poles

Ans: 4

34. A block of mass M is attached to the lower end of a vertical spring. The spring is hung from a ceiling and has force constant value k. The mass is released from rest with the spring initially unstretched. The maximum extension produced in the length of the spring will be:

1) 2 Mg/k

2) 4 Mg/k

3) Mg/2k

4) Mg/k

Ans: 4

35. A bus is moving with a speed of 10 ms-1 on a straight road. A scooterist wishes to overtake the bus in 100 s. If the bus is at a distance of 1 km from the scooterist, with what speed should the scooterist chase the bus?

1) 40 ms-1

2) 25 ms-1

3) 10 ms-1

4) 20 ms-1

Ans: 4

36. Sodium has body centred packing. Distance between two nearest atoms is 3.7 Å. The lattice parameter is:

1) 4.3 Å

2) 3.0 Å

3) 8.6 Å

4) 6.8 Å

Ans: 1

37. The internal energy change in a system that has absorbed 2 Kcals of heat and done 500 J of work is:

1) 6400 J

2) 5400 J

3) 7900 J

4) 8900 J

Ans: 3

38. Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be:

1) 3C, V/3

2) C/3, 3V

3) 3C, 3V

4) C/3, V/3

Ans: 2

39. An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, 1 kg first part moving with a velocity of 12 ms-1 and 2 kg second part moving with a velocity of 8 ms-1. If the third part flies off with a velocity of 4 ms-1, its mass would be: 1) 7 kg

2) 17 kg

3) 3 kg

4) 5 kg

Ans: 4

40. A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is S1 and that covered in the first 20 seconds is S2, then:

1) S2 = 3S1

2) S2 = 4S1

3) S2 = S1

4) S2 = 2S1

Ans: 2

41. A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (g = 10 m/s2)

1) 30 J

2) 40 J

3) 10 J

4) 20 J

Ans: 4

42. A conducting circular loop is placed in a uniform magnetic field 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cm is:

1) 4.8 π µV

2) 0.8 π µV

3) 1.6 π µV

4) 3.2 π µV

Ans: 4

43. The magnetic force acting on a charged particle of charge -2 µC in a magnetic field of 2T acting in y direction, when the particle velocity is (2î + 3ĵ) × 106 ms-1, is:

1) 4 N is z direction

2) 8 N is y direction

3) 8 N in z direction

4) 8 N in -z direction

Ans: 4

44. The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between:

1) n = 3 to n = 1 states

2) n = 2 to n = 1 states

3) n = 4 to n = 3 states

4) n = 3 to n = 2 states

Ans: 3

45. Under the influence of a uniform magnetic field, a charged particle moves with constant speed V in a circle of radius R. The time period of rotation of the particle:

1) depends on R and not on V

2) is independent of both V and R

3) depends on both V and R

4) depends on V and not on R

Ans: 2

1) acceleration = - k(x + a)

2) acceleration = k(x + a)

3) acceleration = kx

4) acceleration = - k0x + k1x2

Ans: 1

33. If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is:

1) repelled by the north pole and attracted by the south pole

2) attracted by the north pole and repelled by the south pole

3) attracted by both the poles

4) repelled by both the poles

Ans: 4

34. A block of mass M is attached to the lower end of a vertical spring. The spring is hung from a ceiling and has force constant value k. The mass is released from rest with the spring initially unstretched. The maximum extension produced in the length of the spring will be:

1) 2 Mg/k

2) 4 Mg/k

3) Mg/2k

4) Mg/k

Ans: 4

35. A bus is moving with a speed of 10 ms-1 on a straight road. A scooterist wishes to overtake the bus in 100 s. If the bus is at a distance of 1 km from the scooterist, with what speed should the scooterist chase the bus?

1) 40 ms-1

2) 25 ms-1

3) 10 ms-1

4) 20 ms-1

Ans: 4

36. Sodium has body centred packing. Distance between two nearest atoms is 3.7 Å. The lattice parameter is:

1) 4.3 Å

2) 3.0 Å

3) 8.6 Å

4) 6.8 Å

Ans: 1

37. The internal energy change in a system that has absorbed 2 Kcals of heat and done 500 J of work is:

1) 6400 J

2) 5400 J

3) 7900 J

4) 8900 J

Ans: 3

38. Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be:

1) 3C, V/3

2) C/3, 3V

3) 3C, 3V

4) C/3, V/3

Ans: 2

39. An explosion blows a rock into three parts. Two parts go off at right angles to each other. These two are, 1 kg first part moving with a velocity of 12 ms-1 and 2 kg second part moving with a velocity of 8 ms-1. If the third part flies off with a velocity of 4 ms-1, its mass would be: 1) 7 kg

2) 17 kg

3) 3 kg

4) 5 kg

Ans: 4

40. A particle starts its motion from rest under the action of a constant force. If the distance covered in first 10 seconds is S1 and that covered in the first 20 seconds is S2, then:

1) S2 = 3S1

2) S2 = 4S1

3) S2 = S1

4) S2 = 2S1

Ans: 2

41. A body of mass 1 kg is thrown upwards with a velocity 20 m/s. It momentarily comes to rest after attaining a height of 18 m. How much energy is lost due to air friction? (g = 10 m/s2)

1) 30 J

2) 40 J

3) 10 J

4) 20 J

Ans: 4

42. A conducting circular loop is placed in a uniform magnetic field 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cm is:

1) 4.8 π µV

2) 0.8 π µV

3) 1.6 π µV

4) 3.2 π µV

Ans: 4

43. The magnetic force acting on a charged particle of charge -2 µC in a magnetic field of 2T acting in y direction, when the particle velocity is (2î + 3ĵ) × 106 ms-1, is:

1) 4 N is z direction

2) 8 N is y direction

3) 8 N in z direction

4) 8 N in -z direction

Ans: 4

44. The ionization energy of the electron in the hydrogen atom in its ground state is 13.6 eV. The atoms are excited to higher energy levels to emit radiations of 6 wavelengths. Maximum wavelength of emitted radiation corresponds to the transition between:

1) n = 3 to n = 1 states

2) n = 2 to n = 1 states

3) n = 4 to n = 3 states

4) n = 3 to n = 2 states

Ans: 3

45. Under the influence of a uniform magnetic field, a charged particle moves with constant speed V in a circle of radius R. The time period of rotation of the particle:

1) depends on R and not on V

2) is independent of both V and R

3) depends on both V and R

4) depends on V and not on R

Ans: 2

46. A thin circular ring of mass M and radius R is rotating in a horizontal plane about an axis vertical to its plane with a constant angular velocity If two objects each of mass m be ω. attached gently to the opposite ends of a diameter of the ring, the ring will then rotate with an angular velocity:

1) ωM/(M + 2m)

2) (ω(M + 2m))/M

3) ωM/(M + m)

4) (ω(M - 2m))/(M + 2m)

Ans: 1

47. In thermodynamic processes which of the following statements is not true?

1) In an isochoric process pressure remains constant

2) In an isothermal process the temperature remains constant

3) In an adiabatic process PVγ = constant

4) In an adiabatic process the system is insulated from the surroundings

Ans: 1

48. The number of photo electrons emitted for light of a frequency v (higher than the threshold frequency v0) is proportional to:

1) Threshold frequency (v0)

2) Intensity of light

3) Frequency of light (v)

4) v - v0

Ans: 2

49. A simple pendulum performs simple harmonic motion about x = 0 with an amplitude a and time period T. The speed of pendulum at x = a/2 will be :

1) πa/T

2) (3π2a)/T

3) (πa√(3))/T

4) (πa√(3))/2T

Ans: 3

50. The two ends of a rod of length L and a uniform cross-sectional area A are kept at two temperatures T 1 and T 2 (T 1 > T 2). The rate of heat transfer, (dQ/dt) through the rod in a steady state is given by:

1) dQ/dt = (k(T 1 - T 2))/LA

2) dQ/dt = kLA(T 1 - T 2)

3) dQ/dt = (kA(T 1 - T 2))/L

4) dQ/dt = (kL(T 1 - T 2))/A

Ans: 3

51. A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength:

1) 4000 nm

2) 6000 nm

3) 4000 Å

4) 6000 Å

Ans: 3

52. If the dimensions of a physical quantity are given by M a Lb T c, then the physical quantity will be:

1) Velocity if a = 1, b = 0, c = - 1

2) Acceleration if a = 1, b = 1, c = - 2

3) Force if a = 0, b = - 1, c = - 2

4) Pressure if a = 1, b = - 1, c = - 2

Ans: 4

53. A transistor is operated in common-emitter configuration at Vc = 2 V such that a change in the base current from 100µA to 200µA produces a change in the collector current from 5 mA to 10 mA. The current gain is:

1) 100

2) 150

3) 50

4) 75

Ans: 3

54. The mass of a lift is 2000 kg. When the tension in the supporting cable is 28000 N, then its acceleration is:

1) 4 ms−2 upwards.

2) 4 ms−2 downwards.

3) 14 ms−2 upwards.

4) 30 ms−2 downwards.

Ans: 1

55. Four identical thin rods each of mass M and length l, form a square frame. Moment of inertia of this frame about an axis through the centre of the square and perpendicular to its plane is :

1) (2/3) Ml2

2) (13/3) Ml2

3) (1/3) Ml2

4) (4/3) Ml2

Ans: 4

56. Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the strings vibrate simultaneously the number of beats is:

1) 7

2) 8

3) 3

4) 5

Ans: 1

57. The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an:

1) isomer of parent

2) isotone of parent

3) isotope of parent

4) isobar of parent

Ans: 3

58. A black body at 227°C radiates heat at the rate of 7 Cals/cm 2s. At a temperature of 727°C, the rate of heat radiated in the same units will be:

1) 50

2) 112

3) 80

4) 60

Ans: 2

59. The driver of a car travelling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is:

1) 555.5 Hz

2) 720 Hz

3) 500 Hz

4) 550 Hz

Ans: 2

60. A galvanometer having a coil resistance of 60 Ω shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by:

1) putting in series a resistance of 15 Ω

2) putting in series a resistance of 240 Ω

3) putting in parallel a resistance of 15 Ω

4) putting in parallel a resistance of 240 Ω

Ans: 3

61. Three concentric spherical shells have radii a, b and c (a < b < c) and have surface charge densities σ, -σ and σ respectively. If V A, VB and VC denote the potentials of the three shells, then for c = a + b, we have:

1) VC = VB ≠ VA

2) VC ≠ VB ≠ VA

3) VC = VB = VA

4) VC = VA ≠ VB

Ans: 4

62. An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?

1) mv2

2) (1/2)mv2

3) (1/2)m 2v2

4) (1/2)mv3

Ans: 4

63. A bar magnet having a magnetic moment of 2 × 104 JT -1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 × 10-4 T exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction 60° from the field is:

1) 12 J

2) 6 J

3) 2 J

4) 0.6 J

Ans: 2

64. In a Rutherford scattering experiment when a projectile of charge z1 and mass M 1 approaches a target nucleus of charge z2 and mass M 2, the distance of closest approach is r0. The energy of the projectile is:

1) directly proportional to z1 z2

2) inversely proportional to z1

3) directly proportional to mass M 1

4) directly proportional to M 1 × M 2

Ans: 1

65. A wave in a string has an amplitude of 2 cm. The wave travels in the + ve direction of x axis with a speed of 128 m/sec. and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is:

1) y = (0.02) m sin (15.7x - 2010t)

2) y = (0.02) m sin (15.7x + 2010t)

3) y = (0.02) m sin (7.85x - 1005t)

4) y = (0.02) m sin (7.85x + 1005t)

Ans: 3

1) ωM/(M + 2m)

2) (ω(M + 2m))/M

3) ωM/(M + m)

4) (ω(M - 2m))/(M + 2m)

Ans: 1

47. In thermodynamic processes which of the following statements is not true?

1) In an isochoric process pressure remains constant

2) In an isothermal process the temperature remains constant

3) In an adiabatic process PVγ = constant

4) In an adiabatic process the system is insulated from the surroundings

Ans: 1

48. The number of photo electrons emitted for light of a frequency v (higher than the threshold frequency v0) is proportional to:

1) Threshold frequency (v0)

2) Intensity of light

3) Frequency of light (v)

4) v - v0

Ans: 2

49. A simple pendulum performs simple harmonic motion about x = 0 with an amplitude a and time period T. The speed of pendulum at x = a/2 will be :

1) πa/T

2) (3π2a)/T

3) (πa√(3))/T

4) (πa√(3))/2T

Ans: 3

50. The two ends of a rod of length L and a uniform cross-sectional area A are kept at two temperatures T 1 and T 2 (T 1 > T 2). The rate of heat transfer, (dQ/dt) through the rod in a steady state is given by:

1) dQ/dt = (k(T 1 - T 2))/LA

2) dQ/dt = kLA(T 1 - T 2)

3) dQ/dt = (kA(T 1 - T 2))/L

4) dQ/dt = (kL(T 1 - T 2))/A

Ans: 3

51. A p-n photodiode is fabricated from a semiconductor with a band gap of 2.5 eV. It can detect a signal of wavelength:

1) 4000 nm

2) 6000 nm

3) 4000 Å

4) 6000 Å

Ans: 3

52. If the dimensions of a physical quantity are given by M a Lb T c, then the physical quantity will be:

1) Velocity if a = 1, b = 0, c = - 1

2) Acceleration if a = 1, b = 1, c = - 2

3) Force if a = 0, b = - 1, c = - 2

4) Pressure if a = 1, b = - 1, c = - 2

Ans: 4

53. A transistor is operated in common-emitter configuration at Vc = 2 V such that a change in the base current from 100µA to 200µA produces a change in the collector current from 5 mA to 10 mA. The current gain is:

1) 100

2) 150

3) 50

4) 75

Ans: 3

54. The mass of a lift is 2000 kg. When the tension in the supporting cable is 28000 N, then its acceleration is:

1) 4 ms−2 upwards.

2) 4 ms−2 downwards.

3) 14 ms−2 upwards.

4) 30 ms−2 downwards.

Ans: 1

55. Four identical thin rods each of mass M and length l, form a square frame. Moment of inertia of this frame about an axis through the centre of the square and perpendicular to its plane is :

1) (2/3) Ml2

2) (13/3) Ml2

3) (1/3) Ml2

4) (4/3) Ml2

Ans: 4

56. Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the strings vibrate simultaneously the number of beats is:

1) 7

2) 8

3) 3

4) 5

Ans: 1

57. The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter is an:

1) isomer of parent

2) isotone of parent

3) isotope of parent

4) isobar of parent

Ans: 3

58. A black body at 227°C radiates heat at the rate of 7 Cals/cm 2s. At a temperature of 727°C, the rate of heat radiated in the same units will be:

1) 50

2) 112

3) 80

4) 60

Ans: 2

59. The driver of a car travelling with speed 30 m/sec towards a hill sounds a horn of frequency 600 Hz. If the velocity of sound in air is 330 m/s, the frequency of reflected sound as heard by driver is:

1) 555.5 Hz

2) 720 Hz

3) 500 Hz

4) 550 Hz

Ans: 2

60. A galvanometer having a coil resistance of 60 Ω shows full scale deflection when a current of 1.0 amp passes through it. It can be converted into an ammeter to read currents upto 5.0 amp by:

1) putting in series a resistance of 15 Ω

2) putting in series a resistance of 240 Ω

3) putting in parallel a resistance of 15 Ω

4) putting in parallel a resistance of 240 Ω

Ans: 3

61. Three concentric spherical shells have radii a, b and c (a < b < c) and have surface charge densities σ, -σ and σ respectively. If V A, VB and VC denote the potentials of the three shells, then for c = a + b, we have:

1) VC = VB ≠ VA

2) VC ≠ VB ≠ VA

3) VC = VB = VA

4) VC = VA ≠ VB

Ans: 4

62. An engine pumps water continuously through a hose. Water leaves the hose with a velocity v and m is the mass per unit length of the water jet. What is the rate at which kinetic energy is imparted to water?

1) mv2

2) (1/2)mv2

3) (1/2)m 2v2

4) (1/2)mv3

Ans: 4

63. A bar magnet having a magnetic moment of 2 × 104 JT -1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 × 10-4 T exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction 60° from the field is:

1) 12 J

2) 6 J

3) 2 J

4) 0.6 J

Ans: 2

64. In a Rutherford scattering experiment when a projectile of charge z1 and mass M 1 approaches a target nucleus of charge z2 and mass M 2, the distance of closest approach is r0. The energy of the projectile is:

1) directly proportional to z1 z2

2) inversely proportional to z1

3) directly proportional to mass M 1

4) directly proportional to M 1 × M 2

Ans: 1

65. A wave in a string has an amplitude of 2 cm. The wave travels in the + ve direction of x axis with a speed of 128 m/sec. and it is noted that 5 complete waves fit in 4 m length of the string. The equation describing the wave is:

1) y = (0.02) m sin (15.7x - 2010t)

2) y = (0.02) m sin (15.7x + 2010t)

3) y = (0.02) m sin (7.85x - 1005t)

4) y = (0.02) m sin (7.85x + 1005t)

Ans: 3