Physics Jamb CBT 3 Only

1. The phenomenon that makes sound persist when its source has been removed is known as

2. The pressure of 3 moles of an ideal gas at a temperature of 27°C having a volume of 10^-3 m3 is

3.

The diagram above represents a transverse electromagnetic wave travelling with speed of 3.0 x 10^8ms-1. What is the frequency of the wave?

4. The velocity y of a particle in a time t is given by the equation
y = 10 + 2t^2
Find the instantaneous acceleration after 5 seconds

5. A simple pendulum has a period of 17.0s. When the length is shortened by 1.5m, its period is 8.5s. Calculate the original length of the pendulum

6. A sonometer wire is vibrating at frequency fo. If the tension in the wire is doubted while the length and the mass per unit length are kept constant, the new frequency of vibration is

7. A travelling wave moving from left to right has an amplitude of 0.15m, a frequency of 550Hz and a wavelength of 0.01m. The equation describing the wave is

8. A transverse wave is applied to a string whose mass per unit length is 3 x 10-2kgm-1. If the string is under a tension 1.2N, the speed of the propagation of the wave is

9. When a brick is taken from the earth’s surface to the moon, its mass

10. If an object just begins to slide on a surface inclined at 30o to the horizontal, the coefficient of friction is

11. Water does not drop through an open umbrella of silk materials unless the inside of the umbrella is touched. This is due to

12. The stylus of a phonograph record exerts a force of 7.7 x 10-2N on a groove of radius 10-5m. Compute the pressure exerted by the stylus on the groove

13. A 90cm uniform lever has a load of 30N suspended at 15cm from one of its ends. If the fulcrum is at the centre of gravity, the force that must be applied at its other end to keep it in horizontal equilibrium is

14. Thermal equilibrium between two objects exist when

15. An open pipe closed at one end produces its first fundamental note. If the velocity of sound in air is P and t the length of the pipe, the frequency of the note is

16. On a fairly cool rainy day when the temperature is 20oC, the length of a steel railroad track is 20m. What will be its length on a hot a dry day when the temperature is 40oC?
[coefficient of linear expansion of steel = 11 x 10-6K-1]

17. If the distance from a point source of sound is doubled, by what factor does the intensity decrease?

18. A 2000W electric heater is used to heat a metal object of mass 5kg initially at 10oC. If a temperature rise of 30oC is obtained after 10min, the heat capacity of the material is

19. If the angle between two vector P and Q is 0°, the vectors are said to

20. A body of mass 4kg is acted on by a constant force of 12N for 3 seconds. The kinetic energy gained by the body at the end of the time is

21. A machine whose efficiency is 60% has a velocity ratio of 5. If a force of 500N is applied to lift a load P, what is the magnitude of P?

22. In which of the following material media will sound travel fastest?

23. In a hydraulic press, a force of 40N is applied on the effort piston of area 0.4m2. If the force exerted on the load piston is 400N, the area of the large piston is

24. The pitch of a sound note depends on

25. The change in volume when 450kg of ice is completely melted is
[density of ice = 900 kgm-3, density of water = 100 kgm-3]

26. Tea pots are often silver-coated to prevent heat loss by

27.
I. Wavelength
II. Medium of propagation
III. Wave velocity
IV. Frequency
V. Energy

Which of the above are used for characterizing waves?

28. A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed the result is that Y has

29. An electric cell with nominal value voltage E has a resistance of 3Ω connected across it. If the voltage falls to 0.6E, the internal resistance of the cell is

30. A ray of light which strikes a glass slab from air at normal incidence passes through the slab

31. A coin placed below a rectangular glass block of thickness 9cm and refractive index 1.5 is viewed vertically above the block. The apparent displacement of the coin is

32. If an object is placed between two parallel plane mirrors with their reflecting surfaces facing each other. How many images of the object will be formed?

33. A ray incident on a glass prism undergoes minimum deviation when the

34.
I. it retains its magnetism much longer than steel
II. it is more easily magnetised than steel
III. it is more easily demagnetized than steel
IV. it produces a stronger magnet than steel
Which combination of the above makes iron preferable to steel in the making of electromagnets?

35. A wire of 5Ω resistance is drawn out so that its new length is two times the original lenght. If the resistivity of the wire remains the same and the cross-sectional area is halved, the new resistance is

36. A magnetic field is said to exist at a point if a force is

37. In a fission process, the decrease in mass is 0.01%. how much energy could be obtained from the fission of 1.0g of the material? [c = 3x108m/s]

38. X-ray can be used in the study of crystal structure because they

39. A radioactive has a decay constant of 10^-8 s-1. The average life of the radioisotope is

40. Fluorescent tubes produce light by

41. The instrument used for securing a large number of similar charges by induction is called

42. The energy stored in an inductor of inductance 5mH when a current of 6A flows through it is

43. In a reverse-biased junction diode, current flows with the help of?

44. An a.c. circuit of e.m.f 12V has a resistor of resistance 8Ω connected in series to an inductor of inductive reactance 16Ω and a capacitor of capacitive reactance 10Ω. The current flow in the circuit is

Hint for solution:

45. The difference between X-ray and gamma rays is that

46. To protect a material from the influence of an external magnetic field, the material should be kept in a?

47. What happens to the rays in a parallel beam of light?

48. The refractive index of the medium M, in the diagram below is

49. What types of mirrors are capable of producing parallel beams of light such as those arising from the head lamps of a car?

50. If u is the object distance and v the image distance which of the following expressions gives the linear magnification produced by a convex lens of focal length F?

51. The ray which causes gas molecules to glow is known as

52. A proton moving with a speed of 1.0x106m/s through a magnetic field of 1.0T experiences a magnetic force of magnitude 8.0×10-14N. the angle between the proton velocity and the field is
[proton charge = 1.6×10-19C

53. The north pole of a magnet can never be separated from the south pole because of a property known as

54. Satellite communication network makes use of