## Class 11 Physics Objective Chapter – 15 Waves

Here we are providing NCERT Class 11 Physics Objective Chapter – 15 Waves Chapter Wise MCQs for board exam is very important for board exam preparation. This book explains all the concepts and topics in very simple language that the students can easily understand the complex subjects also. This NCERT Class 11 Physics MCQs Chapter – 15 Waves Chapter consist all important topic regarding NCERT Class 11 Physics Objective Chapter – 15 Waves. This book basically covers all the major and minor elements that together form a democratic government. Topics like power-sharing, federalism, democracy and diversity, political parties, consequences of democracy, challenges to democracy etc. have been discussed in the NCERT Class 11 Physics Objective Chapter – 15 Waves. The question papers in CBSE board exams are generally based on the latest NCERT books. Hence, students must follow the NCERT book to prepare effectively for their Class 11 Physics exam. If you want color notes then click here

## Class 11 Physics Objective Chapter – 15 Waves

1. A resonance air column of length 40 cm resonates with a tuning fork of frequency 450 Hz. Ignoring end correction, the velocity of sound in air will be

( a )  720 m/s

( b )  820 m/s

( c )  920 m/s

( d )  1020 m/s

Ans:-( a )

2.The speed of sound in a medium depends upon

( a )  its elasticity as well as its inertia.

( b )  its elasticity but not its inertia.

( c )  its inertia but not its elasticity.

( d )  neither its elasticity nor its inertia

Ans:-( a )

3. Name the characteristics of the sound that are affected by the change in temperature.

( a ) amplitude

( b ) frequency

( c ) intensity

( d ) wavelength

Ans:-( d )

4.An observer is moving towards a stationary source of frequency 250 Hz with a velocity of 40 m/s. If the velocity of sound is 330 m/s, the apparent frequency heard by the observer will be

( a )  320 Hz

( b )  300 Hz

( c )  280 Hz

( d )  260 Hz

Ans:-( c )

5. Which of the following are mechanical waves

( a )  Water waves

( b )  Sound waves

( c )  Seismic waves

( d )  All

Ans:-( d )

6. A complete cycle of wave is around

( a ) 45°

( b ) 90°

( c ) 180°

( d ) 360°

Ans:-( d )

7. With the increase in temperature, the frequency of the sound from an organ pipe

( a )  Decreases

( b )  Increases

( c )  Remain unchanged

( d )  Changes erratically

Ans:-( b )

8. Loudness of a note of sound is

( a )  Directly proportional to amplitude of the wave

( b )  Directly proportional to square of amplitude of wave

( c )  Directly proportional to velocity of the wave

( d )  Directly proportional to square of velocity of the wave

Ans:-( b )

9. The velocity of sound in a gas is proportional to:

( a )  the isothermal elasticity.

( b )  the adiabatic elasticity.

( c )  square root of the isothermal elasticity.

( d )  square root of the adiabatic elasticity.

Ans:-( d )

10.In the longitudinal waves the direction of vibration in medium of particle is

( a ) Perpendicular to propagation of wave

( b ) Parallel to propagation

( c ) Different from each other

( d ) Variable for time to time

Ans:-( b )

11. The frequency of the note produced by plucking a given string increases as

( a )  The length of the string increases

( b )  The tension in the string increases

( c )  The tension in the string decreases

( d )  The mass per unit length of the string increases

Ans:-( b )

12. Which of the following are electromagnetic waves

( a )  Light

( c )  X rays

( d )  All

Ans:-( d )

13.The frequency of the note produced by plucking a given string increases as

( a )  The length of the string increases

( b )  The tension in the string increases

( c )  The tension in the string decreases

( d )  The mass per unit length of the string increases

Ans:-( b )

14.Whenever a wave enters from one medium to the another, its

( a )  velocity changes.

( b )  frequency changes.

( c )  frequency does not change.

( d )  wavelength remains constant.

Ans:-( c )

15.Energy is not carried by

( a ) Longitudinal progressive waves

( b ) Electromagnetic waves

( c ) Transverse progressive waves

( d ) Stationary wave

Ans:-( d )

16.A siren placed at a railway platfrom is emitting sound of frequency 5 kHz. A passenger sitting in a moving train A records a frequency of 5.5 kHz while the train approaches the siren. During his return journey in a different train B he records a frequency of 6.0 kHz while approaching the same siren. The ratio of velocity of train B to that of train A is

( a )  242 / 252

( b )  2

( c )  5 / 6

( d )  11 / 6

Ans:-( b )

17.Electromagnetic waves

( a )  Requires material medium for their propagation

( b )  Do not require material medium for their propagation

( c )  Both a and b

( d )  None

Ans:-( b )

18.The extension in a string, obeying Hookes law is X. The speed of sound in the stretched string is V. If the extension in the string is increased to 1.5 X, the speed of sound will be

( a )  1.22 V

( b )  0.61 V

( c )  1.50 V

( d )  0.75 V

Ans:-( a )

19.The velocity of sound in any gas depends upon

( a )  wavelength of sound only.

( b )  amplitude and frequency of sound.

( c )  density and elasticity of the gas.

( d )  intensity of sound waves only

Ans:-( c )

20.When a sound wave goes from one medium to another, the quantity that remains unchanged is

( a ) frequency

( b ) wavelength

( c ) amplitude

( d ) speed

Ans:-( a )

21.The extension in a string, obeying Hookes law is X. The speed of sound in the stretched string is V. If the extension in the string is increased to 1.5 X, the speed of sound will be

( a )  1.22 V

( b )  0.61 V

( c )  1.50 V

( d )  0.75 V

Ans:-( a )

22.______ waves can travel through vacuum

( a )  Sound waves

( b )  Light waves

( d )  Both b and c

Ans:-( d )

23.When two waves meet, their displacements

( b ) cancel out

( c ) destruct each other

( d ) subtract down

Ans:-( a )

24.The extension in a string, obeying Hookes law is X. The speed of sound in the stretched string is V. If the extension in the string is increased to 1.5 X, the speed of sound will be

( a )  1.22 V

( b )  0.61 V

( c )  1.50 V

( d )  0.75 V

Ans:-( a )

25.Four wires of identical lengths, diameters and material and stretched on a sonometer box. The ratio of their tension is 1 : 4 : 9 : 16. the ratio of their fundamental frequencies is

( a )  1 : 6 : 9 : 16

( b )  4 : 3 : 2 : 1

( c )  1 : 2 : 3 : 4

( d )  1 : 4 : 9 : 16

Ans:-( c )

26.The elastic or matter waves in a solid are

а )  longitudinal.

( b )  transverse.

( c )  either longitudinal or transverse.

( d )  neither longitudinal nor transverse.

Ans:-( c )

27.Sound travels in rocks in the form of

( a ) both longitudinal and transverse elastic waves

( b ) non-elastic waves

( c ) transverse elastic waves only

( d ) longitudinal elastic waves only

Ans:-( a )

28.The extension in a string, obeying Hookes law is X. The speed of sound in the stretched string is V. If the extension in the string is increased to 1.5 X, the speed of sound will be

( a )  1.22 V

( b )  0.61 V

( c )  1.50 V

( d )  0.75 V

Ans:-( a )

29.The speed of electromagnetic waves is

( a )  299,792,458 m/s

( b )  299, 792, 458 km/s

( c )  299, 792, 458 cm/s

( d )  None

Ans:-( a )

30. As wave travels, intensity of wave

( a ) decreases

( b ) increases

( c ) doesn’t change

( d ) becomes zero

Ans:-( a )

31.Energy is to be carried from one place to another. Which one of the following cannot be used?

( a )  Longitudinal progressive waves

( b )  Transverse progressive waves

( c )  Electromagnetic waves

( d )  Standing ( stationary )  waves

Ans:-( d )

32.The equation of wave traveling along string is y = 3 cos p ( 100t – x )  in C.G.S. unit then wavelength is

( a )  1 m

( b )  2 cm

( c )  5 cm

( d )  None of above

Ans:-( b )

33.With the propagation of longitudinal wave through a material medium, the quantities transmitted in the propagation direction are

( a )  energy.

( b )  energy and linear momentum.

( c )  energy and mass.

( d )  energy, mass and momentum

Ans:-( a )

34. Two tuning forks of frequencies 256 and 258 vibrations/second are sounded together. Then the time interval between two consecutive maxima heard by an observer is

( a ) 2 sec

( b ) 0.5 sec

( c ) 250 sec

( d ) 252 sec

Ans:-( b )

35.Energy is to be carried from one place to another. Which one of the following cannot be used?

( a )  Longitudinal progressive waves

( b )  Transverse progressive waves

( c )  Electromagnetic waves

( d )  Standing ( stationary )  waves

Ans:-( d )

36.Pressure is given by

( a )  F/m

( b )  F/V

( c )  F/A

( d )  FA

Ans:-( c )

37.A complete cycle of wave is around

( a ) 45°

( b ) 90°

( c ) 180°

( d ) 360°

Ans:-( d )

38.To demonstrate the phenomenon of beats we need

( a )  Two sources which emit radiation of nearly the same frequency

( b )  Two sources which emit radiation of exactly the same frequency

( c )  Two sources which emit radiation of exactly the same frequency and have a definite phase relationship

( d )  Two sources which emit radiation of exactly the same wavelength

Ans:-( a )

39.A resonating column of air contains

( a )  Stationary longitudinal waves

( b )  Stationary transverse waves

( c )  Transverse progressive waves

( d )  Longitudinal progressive waves

Ans:-( a )

40.When a tuning fork vibrates, the waves produced in tuning the Fork are

( a )  transverse both in the prongs and the stem.

( b )  longitudinal in both the prongs and stem.

( c )  longitudinal in stem and transverse in prongs.

( d )  longitudinal in prongs and transverse in the stem.

Ans:-( c )

41.Which of the following expressions is that of a simple harmonic progressive wave

( a ) a sin wt

( b ) a sin ( wt )  cos ( kx )

( c ) a sin ( wt – kx )

( d ) a cos kx

Ans:-( c )

42.A resonating column of air contains

( a )  Stationary longitudinal waves

( b )  Stationary transverse waves

( c )  Transverse progressive waves

( d )  Longitudinal progressive waves

Ans:-( a )

43.Sound waves are the

( a )  Transverse waves

( b )  Longitudinal waves

( c )  Both a and b

( d )  None

Ans:-( b )

44.Frequencies of sound produced from an organ pipe open at both ends are

( a ) even and odd harmonics

( b ) only odd harmonics

( c ) only even harmonics

( d ) none of these

Ans:-( a )

45.When a sound wave goes from one medium to another, the quantity that remains unchanged is

( a )  frequency

( b )  wavelength

( c )  amplitude

( d )  speed

Ans:-( a )