**SAMPLE PAPER / MODEL TEST PAPER**

**SUBJECT – PHYSICS**

**BANARAS HINDU INVERSITY (BHU) MEDICAL ENTRANE EXAMINATION 2012**

1. body of mass 2 kg is moving with velocity 10 m/s towards east. Another body of same mass and same velocity moving towards north collides with former and coalesces and moves towards north – east. Its velocity is:

(a) 10 m/s (b) 5 m/s (c) 2.5 m/s (d) 5 root 2 m/s

2. A force F is applied on a square plate of side L. If the percentage error in the determination of L is 2 % and that in f is 4% what is the permissible in the pressure ?

(a) 2% (b) 4% (c) 6% (d) 8%

3.Two particles A and B are connected by a rigid rod AB. The rod slides along perpendicular rails as shown here. The velocity of a to the left is 10 m/s What is the velocity of B when angle alfa = 60 degree?

(a) 9.8 m/s (b) 10 m/s (c) 5.8 m/s (d) 17.3 m

4. A partile moves towards east with velocity 5 m/s. After 10 s its direction changes towards north with same velocity. The average acceleration of the particle is:

(a) Zero (b) 1/root 2 m/s square N-W

(c) 1/root 2 m/s square N –E (d) 1/root 2 m/s square S –W

5. A car is driven along straight level frictionless road by an engine delivering constant power. Then velocity is directly proportional to:

(a) t (b) 1/root v (c) root t (d) none of these

6. A ball of mass 0.25 kg attached to the end of a string of length 1.96 m is moving in a horizontal circle. The string will break if the tension is more than 25 N. What is the maximum speed with the ball can be moved.

(a) 14 m/s (b) 3 m/s (c) 3.92 m/s (d) 5 m/s

7. A capillary tube when immersed vertically in a liquid records a rise of 3 cm. If the tube is half immersed in the liquid at an angle of 60 degree with the vertical, the length of the liquid column along the tube will be:

(a) 1.5 cm (b) 3.0 cm (c) 2 root 3 cm (d) 6.0 cm

8. The gravitational potential difference between the surface of a planet and a point 20 m above it is 16 J/kg. The work done is moving a 2 kg mass by 8.0 m on a slope of 60 degree from the horizontal is nearest to:

(a) 3.2 J (b) 6.4 J (c) 9.6 J (d) 10.9 J

9. A cylindrical vessel of height 50 cm is filled up to the brim. Holes are made in it at heights 15 cm, 30 cm and 45 cm. From which hole will the water have maximum horizontal range?

(a) 15 cm (b) 30 cm (c) 40 cm (d) 45 cm

10. A cylinder contains helium at 2.5 ATM pressure Another identical cylinder contains argon at 1.5 ATM pressure at the same temperature . If both the gases are filled in any one of the cylinder, the pressure of the mixture will be:

(a) 4 ATM (b) 2.5 ATM (c) 1.5 ATM (d) none of these

11. What happens when a sound wave is reflected from the boundary of a denser medium? The compression of the incident wave is returned as;

(a) trough (b) rarefaction (c) crest (d) compression

12. Radio Waves of wavelength ג are sent from RADAR towards an aeroplane. If the aeroplane is moving towards the RADAR station, the wavelength of the radio waves, received after reflection from the aeroplane will be:

(a) ג

(b) less than ג

(c) more than ג

(d) more or less than ג , depending on the speed of aeroplane

13. The acceleration due to gravity at a place is g. A ball of density ρ is gently released in fluid of density σ. What will be the downward acceleration of the ball if ρ > σ ?

(a) g (b) g σ/ ρ (c) g (1 – σ/ ρ ) (d)√ g (1 – σ/ ρ )

14. A particle executes SHM along a straight line path. Its amplitude is A. The potential energy of the particle is equal to kinetic energy , when the displacement of the particle from mean position is:

(a) Zero (b) ± A/2 (c) ± A/√2 (d) ) ± A

15. The capacitance of a parallel plate is 5 μF. When a glass plate a placed between the plates of capacitor, its potential difference is reduced to 1/8 of the original value. The value of the relative dielectric constant of glass is:

(a) 1.6 (b) 5 (c) 8 (d) 40

16. A solid conducting sphere having a charge Q is surrounded by an uncharged concentric conducting hollow spherical shell. Let the potential difference between the surface of the solid sphere and that of the outer surface of the hollow shell be V, If the shell is now given a charge of 3Q the new potential difference between the two surfaces is:

(a) V (b) 2V (c) 4V (d) – 2V

17. Just as electricity is supplied t 240 V for domestic use in India , it is supplied at 110 V in USA. If resistance of 60 W bulb for use in USA will be:

(a) R/4 (b) R/2 (c) R (d) 2R

18. At the magnetic poles of earth a compass needle will be:

(a) vertical (b) bent slightly (c) horizontal (d) inclined at 45 degree to the horizontal

19. A convex lens of focal length 25 cm is placed at a distance x from a concave lens of focal length 7 cm. When a parallel beam is incident on the convex lens it emerges as a parallel beam out of the concave lens. What is the value of x?

(a) 16 cm (b) 18 cm (c) 14 cm (d) 20 cm

20. What determines the half – life of the radioactive element?

(a) Temperature (b) Atomic number (c) Mass number (d) None of these

21. For an atomic reactor being critical the ratio (r) of the average of neutrons produced and used in chain reaction:

(a) is greater than one (b) is less than one

(c) is equal to one (d) depends on the mass of fissionable material

22. The maximum energy of the X –ray photons is 2 KV. What is the accelerating potential applied across the tube?

(a) 1 KV (b) 4 KV (c) 2 KV (d) 8 KV

23. There is a prism with refractive index √2 and the refracting angle 30 degree . One of the refracting surfaces of the prism is polished. A beam of monochromatic light will retrace its path if its angle of incidence over the refracting surface of the prixm is:

(a) 60 degree (b) 30 degree (c) 0 degree (d) 45 degree

24. One mole of a gas at a pressure 2Pa and temperature 27 degree C is heated till both pressure and volume are doubled. What is the temperature of the gas?

(a) 300 K (b) 1200 K (c) 600 K (d) 900 k

24. A microscope is focused on a mark on the piece of paper and than a glass slab of thickness 3 cm and refractive index 1.5 is placed over the mark. How should the microscope be moved to get the mark again in focus?

(a) 1 cm downward (b) 2 cm upward (c) 1 cm upward (d) 4.5 cm downward

25. An object is placed at a distance of 24 cm from the lens and then at a distance of 16 cm from the lens. The magnification of the image formed in both cases is same. What is the focal length of the lens?

(a) 18 cm (b) 20 cm (d) 22 cm (d) None of these

26. There is no hole current is good conductors because:

(a) have neither valence nor conduction bands

(b) they do not have valence band

(c) they do not have conduction band

(d) their valence and conduction bands overlap

27. A spherical charged conductor has σ as the surface density of charge. The electric field on its surface is E. If the radius of the sphere is doubled keeping the surface density of charge unchanged , what will be the electric field on the surface of the new sphere?

(a) E (b) E/2 (c) 2E (d) E/4

28. In the dead beat galvanometer, the coil is wound on a frame made of:

(a) bad conductor (b) magnetic material (c) bad conductor (d) none of these

29. The resistance of the filament of a lamp increases with increase in temperature. A lamp rated 100 W and 220 V is connected across 220 V power supply. If the voltage drops by 10% , then the power of the lamp will be:

(a) 81 W (b) 90W

(c) between 90 W and 100 W (d) between 81 and 90 W

30. A capacitor 2μF is charged by connecting across a battery of 100 V. Another capacitor of 4 μF is charged by connecting across the same battery. If both of them connected to each other in parallel, the potential drop across the combination will be:

(a0 200 V (b) 400 V (d) 50 V (d) 100 V

31. A virtual object between the optical centre and the focus of a concave lens produces:

(a) a virtual and inverted image (b) a real and erect image

(c) a real and inverted image (d) a virtual and erect image

32. If the tube length of astronomical telescope is 105 cm and magnifying power is 20 for normal setting, calculate the focal length of the objective lens.

(a) 10 cm (b) 25 cm (c) 20 cm (d) 100 cm

33. We have a jar a filed with gas characterised by the parameters P, V and T and another jar B filled with a gas with parameters 2P, V/4 and 2T, where the symbols have their usual meanings. The ratio of number of molecules of jar A to those of jar B is:

(a) 1 : 2 (b) 2 : 1 (c) 1 :1 (d) 4 : 1

34. A Young’s double slit set up for interference is shifted from air to within ware, then the fringe width:

(a) become infinite (b) remains (c) decreases (d) increases

35. A particle a suffers an oblique elastic collision with a particle B that is at rest initially. If their masses are the same then after the collision:

(a) A comes to rest and B starts and B starts moving in the direction of the original motion of A

(b) They will move in opposite direction

(c) A continues to move in original direction while B remains at rest

(d) they will move in mutually perpendicular directions

36. In the propagation of electromagnetic waves, the angle between the direction of propagation and plane of polarization is:

(a) 0 degree (b) 90 degree (c) 180 degree (d) 45 degrees

37. The positive terminal of 12 V batteries is connected to the ground. Then the negative terminal will be at:

(a) – 12 (b) -6 (c) + 12 (d) Zero

38. As per Bhor model, the minimum energy (in eV) required to remove the electron the electron from the ground state of doubly ionized lithium (Z = 3) is:

(a) 122.4 (b) 13.6 (c) 1.51 (d) 40.8

39. The half – life of radon is 3.8 days. The time at the end of which 1/20^{th} of the radio sample will remain undecayed is (log e = 0.4343):

(a) 3.8 days (b) 16.5 days (c) 20 days (d) 36 days

40. Two coils x and y are placed in a circuit such that a current changes by 2 A in coil x and the magnetic flux changes by 0.4 Wb in y. the mutual inductance of the coils is:

(a) 0.8 H (b) 0.2 H (c) 5 H (d) 15 H

41. At he magnetic north pole of the earth, the vale of horizontal component of earths magnetic field and angle of dip are, respectively

(a) minimum, minimum

(b) zero, maximum

(c) maximum, minimum

(d) maximum, maximum

42. A pendulum is suspended from the ceiling of the component of a train. When the train is stationary, the time period of the pendulum is T. of the pendulum change?

(a) it will remain unchanged

(b) it will increase

(c) it will decrease

(d) pendulum will not oscillate

43. A thin equiconvex lens has focal length 10 cm refractive index 1.5. One of its faces is now silvered and for an object placed at a distance in front of the mirror image coincides with the object. The value of u is:

(a) 20 cm (b) 10 cm (c) 15 cm (d) 5 m

44. A moving mass of 8 kg collides elastically with a stationary mass of 2 kg. If e be the initial kinetic energy of the moving mass, the kinetic energy left with it after he collision will be:

(a) 0.08 E (b) 0. 64 E (c) 0.8 E (d) 0. 36

45. If pressure of a gas contained in a closed vessel is increased by 0.4% when gated by 1 degree C, its initial temperature must be:

(a) 2500K (b)250 degree (c) 25 degree C (d) 1250 K

46. Which of the following cannot be used to separate isotopes?

(a) Thermal diffusion

(b) Chemical reaction

(c) Electric and magnetic fields

(d) Centrifuge

47. Diffraction pattern cannot be observed with:

(a) one wide slit (b) one narrow slit

(c) two narrow slits (d) large number of narrow slits

48. If 2.2 kW power is transmitted through a 10 Q line at 22000 V, the power loss in the form of heat will be:

(a) 10 W (b) 1 W (c) 100 W (d) 0.1 W

49. The focal length of the objective of an astronomical telescope is 1.0 m if the magnifying power to telescope is 20, then what is the length of the telescope for relaxed eye?

(a) 105 cm (b0 85 cm (c) 115 cm (d) 95 cm

50. Given that the critical angle of a prism40 degree. The maximum angle of prism for which the emergent ray can be obtained is:

(a) 80 degree (b) 60 degree (c) 90 degree (d) 40 degree

Two coils x and y are placed in a circuit such that a current changes by 2 A in coil x and the magnetic flux changes by 0.4 Wb in y. the mutual inductance of the coils is

The half – life of radon is 3.8 days. The time at the end of which 1/20th of the rado sample will remain undecayed is (log e = 0.4343):