Objective paper of ch#7 for FSC aslo for MDCAT and ECAT preparation

Paper for Entry Test Preparation Physics 1^st year Chapter No. 7

Total marks:- 200                                        Time allowed 35 minutes

Note:- Fill the appropriate answer of the following questions in the answer sheet. Double filling and erasing is not allowed. Each question carries equal marks and for each wrong answer minus one is awarded.

1) To and fro motion of a body about its mean position is known as:

                a) Translatory motion              b) Vibratory motion                c) Rotatory motion                  d) Non of all

2) The restoring force is __ and opposite to the applied force within__:

                a) Equal, elastic limit               b) Different, the walls             c) Different, elastic limit          d) Equal, the walls

3) The graph showing the variation of displacement with time is a:

                a) Sine curve                           b) Straight line                         c) Parabolic                             d) Hyperbolic

4) When quarter of a cycle is completed, the phase of vibration is:

                a) 90^o                                       b) 180^o                                    c) 45^o                                       d) 360^o

5) The number of vibrations in two seconds can be expressed as ___ if frequency o vibration is ‘f’:

                a) ‘f’                                        b) ‘2f’                                      c) ‘3f’                                      d) ‘1/2f’

6) In SHM, there is always a constant ratio between displacement of a body and its:

                a) Velocity                               b) Period                                 c) Mass                                   d) Acceleration

7) Hertz is a unit of:

                a) Time period                         b) Displacement                      c) Amplitude                           d) Frequency

8) An object in SHM will have maximum speed when its displacement from equilibrium position is:

                a) Infinity                                b) Maximum                           c) Zero                                     d) Minimum

9) A body executing SHM has displacement equal to:

                a) r sinwt                                 b) r cos²wt                               c) r² coswt                                d) r² sinwt

10) In SHM, the acceleration if __ when velocity is ___:

                a) Zero, smallest                      b) Smallest, zero                      c) Zero, zero                            d) Zero, greatest

11) An oscillating body oscillates due to:

                a) Applied force                      b) Restoring force                   c) Frictional force                    d) Non of all

12) The change in length of the spring in a spring-mass system is directly proportional to:

                a) Frequency                           b) Applied force                      c) Velocity                               d) Non of all

13) In case of spring mass system, the ratio of the applied force to the displacement is called:

                a) Plank’s constant                  b) Decay constant                    c) Spring constant                   d) Acceleration

14) If a body completes 20 vibration in one minute, its time period will be:

                a) 0.05 sec                               b) 1.5 sec                                 c) 3.0 sec                                 d) 20 sec

15) In SHM, the acceleration of the vibrating body is always directed towards:

                a) The point at which the body is attached to the support        b) The point at which force is applied

                c) Towards the mean position                                                 d) It has no acceleration

16) If mass attached to a spring is increased, then its time period:

                a) Remains constant                b) Decreases                            c) Increases                             d) Non of all

17) The equation v_o = x_ow is the equation for:

                a) Spring mass system            b) Simple pendulum                c) Any harmonic oscillator      d) Non of all

18) When the bob of a simple pendulum is at extreme position, its K.E. is __ and P.E. is __:

                a) Maximum, zero                   b) Minimum, zero                   c) Zero, maximum                   d) Zero, zero

19) The time period of a simple pendulum is independent of its:

                a) Length                                 b) Mass                                   c) Value of g                           d) Both (a) and (b)

20) If ration of time period of two pendulum is 1:2, then the ratio of their lengths will be:

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

21) A pendulum execute SHM provided that:

                a) Its bob is too light                                                               b) The string is extensible

                c) The arc through which it swings is not too large d) Non of all

22) Pendulums having same lengths will vibrate with:

                a) Same frequency                   b) Different periods                 c) Different frequencies           d) Non of all

23) If time period of a pendulum is doubled by increasing its length, then its frequency will:

                a) Also be doubled                  b) Become half                        c) Become one fourth              d) Becomes four times

24) The time period of a simple pendulum does not depend upon:

                a) Amplitude                           b) Mass                                   c) Length                                 d) Both (a) and (b)

25) At which place simple pendulum will vibrate the slowest:

                a) Murree                                                b) Karachi                                c) Mount Everest                     d) Same at all places

26) The string of a simple pendulum should be:

                a) Heavy                                  b) Extensible                           c) Inextensible                         d) Hard

27) The tension T in the string of a simple pendulum acts:

                a) Vertically downward           b) Along the string                  c) Vertically upward                d) At any direction

28) The acceleration of the bob of the simple pendulum is given by:

                a) a = -g cosӨ                         b) a = g cosӨ                          c) a = -g Ө                               d) a = g sinӨ

29) Product of time period of a simple pendulum and its frequency is given by:

                a) p                                          b) One                                     c) Öp                                       d) 2 p

30) The frequency of second’s pendulum is:

                a) 0.5 Hz                                 b) 1.0 Hz                                 c) 1.5 Hz                                 d) 2 Hz

31) When time period of a simple pendulum increases, the vibration:

                a) Become fast                         b) Become slow                      c) Are not effected                   d) Non of all

32) A cheap pendulum clock will:

                a) Lose time in summer and gain time in winter                      b) Keep correct time

                c) Gain time in summer and lose time in winter                      d) Non of all

33) The total energy of the mass spring system at any moment during the oscillation is given by:

                a) ½ k x²                                  b) ½ k x_o²                                 c) ½ k x_o                                  d) ½ k x

34) When the mass attaché to a spring passes through its mean position (x = 0), its K.E. is:

                A) Maximum                          b) Minimum                            c) Zero                                     d) Non of all

35) Total energy of a body executing SHM is directly proportional to:

                a) Square of amplitude            b) Amplitude                           c) Square root of amplitude     d) Cube of amplitude

36) Resonance occur when a body is set into vibration at a frequency:

                a) Lower than its natural frequency                                         b) Higher than its natural frequency

                c) Equal to its natural frequency                                              d) Non of all

37) If two systems are in resonance, then their __ are equal:

                a) Amplitudes                          b) Time periods                       c) Temperature                        d) Non of all

38) Heating and cooking of food by microwave oven is an example of:

                a) SHM                                   b) Resonance                           c) Interference                         d) Diffraction

39) Large damping force on a vibrating body means ___ in amplitude:

                a) Small change                       b) Large change                       c) No change                           d) Stop the body

40) Free oscillations are always produced by:

                a) An applied force                  b) Gravitational force              c) Restoring force and inertia  d) Inertia only

41) Resonance can take place:

                a) In friction                            b) In microwave oven             c) In tuning radio                     d) Both (b) and (c)

42) If a body oscillates with its natural frequency without the interference of a external force, then oscillates are called:

                a) Free oscillations                  b) Damped oscillation             c) Forced oscillations              d) Non of all

43) Motion of any macroscopic system is accompanied by:

                a) Electrical effects                  b) Frictional effects                 c) Mechanical effects               d) Non of all

44) At resonance, the amplitude of vibration becomes very ___ when damping is ___:

                a) Small, small                         b) Large, small                        c) Large, large                         d) Small, large

45) Radio set can be tuned only when resonance takes place and at that time, energy:

                a) Absorption is maximum      b) Emission is maximum         c) Is not exchanged at all         d) Non of all

46) In practice, the amplitude of a simple harmonic oscillator gradually becomes __ because of__:

                a) Smaller, friction                   b) Greater, air resistance          c) Smaller, air resistance          d) Both (a) and (b)

47) A shock absorber of a car provides a __ force to ___ successive oscillations:

                a) Damping, allow                   b) Accelerating, prevent          c) Damping, prevent                d) Accelerating small

48) The quantity ‘½ k x_o²’ is the maximum total energy of spring-mass system:

                a) At mean position                 b) At extreme position             c) At any position                    d) Both (a) and (b)

49) The length of second pendulum at a place where g = 980 cm/sec² is:

                a) 77 cm                                  b) 88.1 cm                               c) 99.2 cm                               d) 100.3 cm

50) AT the centre of the earth, the simple pendulum will:

                a) Vibrate with same time period                                             b) Vibrate with double time period

                c) Do not vibrate                                                                     d) Vibrate with half time period