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Free Waves MCQs with Answers

1,281 Waves MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Progressive waves transfer energy through oscillations, with wavelength, frequency, amplitude and wave speed related by v = fλ; sound speed depends on the medium. Superposition produces interference and stationary waves in strings and organ pipes, while simple harmonic motion describes the oscillation itself and must be distinguished from wave propagation.

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Progressive WavesWave SpeedSpeed of SoundSuperposition and InterferenceStationary WavesOrgan PipesSimple Harmonic Motion
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1,281 questions · page 52 of 65

1021. A train has just completed a U-curve in a track which is a semicircle. The engine is at the forward end of the semicircular part of the track while the last carriage is at the rear end of the semi-circular track. The driver blows a whistle of a frequency of 200 Hz. The velocity of sound is 340 m/s. Then the apparent frequency as observed by a passenger in the middle of the train, when the speed of the train is 30 m/s is:

  • A. 219 Hz
  • B. 288 Hz
  • C. 200 Hz
  • D. 181 Hz

Explanation: ∴ There is no relative motion between the source and the observer, hence no change in real frequency is observed.

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Correct answer: 200 Hz

1022. Two particles of a medium disturbed by the wave propagation are at x1=0 and x2=1cm. The respective displacements (in cm) of the particles can be given by the equations: y1=2sin3πt y2=2sin(3πt - π/8) The wave velocity is :

  • A. 16 cm/sec
  • B. 24 cm/sec
  • C. 12 cm/sec
  • D. 8 cm/sec

Explanation: From the given two equations we take the values of ω and ϕ, then use the values to find wavelength and frequency.

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Correct answer: 24 cm/sec

1023. An air column of length L closed at one end is oscillating in 2nd overtone. Pressure change in air is minimum from the closed end at distance of:

  • A. L/4
  • B. L/5
  • C. L/7
  • D. Zero

Explanation: When an air column is closed at one end and oscillates in its second overtone, it means that it vibrates in a mode where there are two…

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Correct answer: Zero

1024. A train moves toward a stationary observer at a speed of 34 m/s. The train sounds a whistle and its frequency registered by the observer is f1. If the train's speed is reduced to 17 m/s, the frequency registered is f2. If the speed of sound is 340 m/s then the ratio f1/f2 is:

  • A. 18/19
  • B. 1/2
  • C. 2
  • D. 19/18

Explanation: Following is the solution to this question:

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Correct answer: 19/18

1025. A siren placed at a railway platform is emitting a 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 on a different train B, he records a frequency of 6.0 kHz while approaching the same siren. The ratio of the velocity of train B to that of train A is:

  • A. 242/252
  • B. 2
  • C. 5/6
  • D. 11/6

Explanation: Following is the solution to this question:

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Correct answer: 2

1026. A tuning fork of 512 Hz is used to produce resonance in a resonance tube experiment. The level of water at the first resonance is 30.7 cm and at the second resonance is 63.2 cm. The error in calculating the velocity of sound is:

  • A. 204.1 cm/s
  • B. 110 cm/s
  • C. 58 cm/s
  • D. 280 cm/s

Explanation: Following is the solution to this question:

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Correct answer: 280 cm/s

1027. Doppler's Effect is applicable to:

  • A. transverse waves
  • B. longitudinal waves
  • C. mechanical waves
  • D. mechanical and electromagnetic waves

Explanation: Correct. The Doppler Effect is applicable to both mechanical waves and electromagnetic waves.

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Correct answer: mechanical and electromagnetic waves

1028. If the distant star is receding from us, the spectral lines from such a star when examined on Earth will show:

  • A. No shift in frequency
  • B. A shift in frequency towards the red end
  • C. A shill in frequency towards the violet end
  • D. shift in frequency towards ultraviolet

Explanation: When a star is moving away from Earth show a red shift. The emitted waves have a longer wavelength than if the star had been at rest.

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Correct answer: A shift in frequency towards the red end

1029. Due to the overlapping of two identical waves the speed of the resultant wave:

  • A. Decrease
  • B. Increase
  • C. Becomes velocity
  • D. Remains same

Explanation: Due to the overlapping of waves the amplitude of wave may change but the speed of wave does not change.

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Correct answer: Remains same

1030. In the following properties of a wave, the one that is independent of the others in its:

  • A. Velocity
  • B. Amplitude
  • C. Frequency
  • D. Wavelength

Explanation: The amplitude of a wave is the maximum displacement of particles in the medium from their rest position.

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Correct answer: Amplitude

1031. The frequency of sound appears 10% less to a moving observer. What is the speed of the observer? (take speed of sound 350 m/s).

  • A. 10 m/s
  • B. 20 m/s
  • C. 35 m/s
  • D. 40 m/s

Explanation: As apparent frequency decreases. So. observer is moving away from the stationary source.

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Correct answer: 35 m/s

1032. Electric and magnetic fields constitute:

  • A. Electromagnetic wave
  • B. Transverse waves
  • C. Longitudinal waves
  • D. Stationary Waves

Explanation: Waves that do not require any medium for their propagation are called electromagnetic waves.

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Correct answer: Electromagnetic wave

1033. Which of the following is not the case of Doppler's effect:

  • A. Option A
  • B. Option B
  • C. Option C
  • D. Option D

Explanation: Except for B, all others are the cases of Doppler effect. A explains an observer moving away from a stationary source.

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Correct answer: Option B

1034. Transverse mechanical waves can propagate:

  • A. both in gas and metal
  • B. in gas but not in metal
  • C. in metal but not in gas
  • D. neither in gas not in metal

Explanation: Transverse and longitudinal waves can be set up in solids. In gases transverse waves die out very quickly and usually cannot be produced…

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Correct answer: in metal but not in gas

1035. A source emits sound with a frequency of 1000 Hz. It and an observer are moving in the same direction with the same speed, 100m/s. If the speed of sound is 340m/s, the observer hears sound with a frequency of:

  • A. 294 Hz
  • B. 1000 Hz
  • C. 545 Hz
  • D. 1830 Hz

Explanation: As there is no relative motion between the source and observer, so apparent change of frequency will not be observed.

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Correct answer: 1000 Hz

1036. If stretching force in a stretched wired is increased then its frequency of oscillation:

  • A. decreases
  • B. increases
  • C. remains same
  • D. none of these

Explanation: f = (1/2L) * √ (T/m) Where: f = frequency of oscillation L = length of the wire T = tension in the wire m = linear density (mass per unit…

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Correct answer: increases

1037. The distance between node and anti-node is 85cm. The velocity of sound is 340 ms-1. The frequency of waves is:

  • A. 100Hz
  • B. 250Hz
  • C. 200Hz
  • D. 340 Hz

Explanation: Please refer to the calculation given below.

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Correct answer: 100Hz

1038. A set of frequencies that are multiples of the fundamental frequency is called:

  • A. Amplitude
  • B. Speed
  • C. Beat frequency
  • D. Harmonics

Explanation: Option d) Harmonics is the correct option. The set of frequencies which are multiples of the fundamental frequency is called harmonics.

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Correct answer: Harmonics

1039. The ratio of the nodes and antinodes for fundamental frequency in a closed pipe system (open at one end is always):

  • A. Less than one
  • B. Greater than one
  • C. Equal to one
  • D. Less than or equal to one

Explanation: For fundamental frequency in closed pipe No. of nodes = No. of antinodes No. of nodes / No. of antinodes = 1

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Correct answer: Equal to one

1040. Oscillating charge produces:

  • A. Mechanical wave
  • B. Electromagnetic wave
  • C. Matter waves
  • D. Longitudinal wave

Explanation: Waves that do not require any medium for their propagation are called electromagnetic waves.

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Correct answer: Electromagnetic wave
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