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Free Superposition and Interference MCQs with Answers

68 Superposition and Interference MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Superposition states that overlapping waves produce a resultant displacement equal to the algebraic sum of their individual displacements. Interference covers constructive and destructive interference, phase difference, path difference, coherent sources, and conditions for maxima and minima. It differs from diffraction, which involves spreading around openings or obstacles.

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68 questions · page 2 of 4

21. Two sitar strings, A and B, are playing the note 'Ga,' are slightly out of tune and produce beats of frequency 6 Hz. The tension in the string A is slightly reduced, and the beat frequency is found to reduce to 3 Hz. If the original frequency of A is 324 Hz, what is the frequency of B?

  • A. 405
  • B. 402
  • C. 395
  • D. 318
  • E. 401

Explanation: The beat frequency is given by the difference in frequency between the two strings:f_beat = |fA - fB|We are given that the original beat…

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Correct answer: 318

22. In a double-slit experiment, two slits are 0.2 mm apart with a screen at a distance of 1m. The third bright fringe is found to be displaced at a distance of 7.5 mm from the central fringe. What is the value of the wavelength?

  • A. 0.03 mm
  • B. 0.004 mm
  • C. 0.00006 mm
  • D. 0.0005 mm

Explanation: The explanation is given below:In the double slit experiment, the position of bright fringes is given by the equation:y = (mλD)/dWhere y…

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Correct answer: 0.0005 mm

23. In interference pattern energy is?

  • A. Created at the maximum position
  • B. Destroyed at the position of minimum
  • C. Conserved but redistributed
  • D. Both conserved

Explanation: Ar = A1 + A2 (Constructive)Ar = A1 - A2 (Destructive)As the intensity is directly propotional to square of amplitudeI = k.A2 (k=1)I =…

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Correct answer: Conserved but redistributed

24. When two or more waves overlap at the same time the resultant wave will be the sum of individual waves. The principle is known as

  • A. Reflection.
  • B. Ultrasonic.
  • C. Supersonic.
  • D. Superposition.

Explanation: The correct answer is superposition. The principle of superposition describes how when two or more waves overlap, their individual…

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Correct answer: Superposition.

25. While travelling by a boat, we hear the siren of a nearby ship at certain points but not at some other points. This phenomenon is caused by

  • A. Formation of beats.
  • B. Destructive interference.
  • C. Production of resonance.
  • D. Constructive interference.

Explanation: The correct answer is destructive interference. This phenomenon occurs when two sound waves meet in such a way that the crest of one wave…

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Correct answer: Destructive interference.

26. In Young's double slits experiment, the relation used to find the position of the dark fringes is(Note: All the symbols have their usual meaning.)

  • A. Y = (m+1) λL/d
  • B. Y = (m - 1)λL/d
  • C. Y = (m + 1/2)λL/d
  • D. Y = (m - 1/2) λd/L

Explanation: In Young's double-slit experiment, the position of the dark fringes is given by the formula Y = (m + 1/2)λL/d, where m is the order of the…

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Correct answer: Y = (m + 1/2)λL/d

27. Soap films are thin layers of liquid usually water-based surrounded by air in the sunlight colours are visible on the surface of them due to

  • A. Scattering of light
  • B. Dispersion of light
  • C. Diffraction of light
  • D. Interference of light

Explanation: The correct answer is interference of light. In soap films, colors are visible due to the interference of light.

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Correct answer: Interference of light

28. Loud music produced by beating wooden drum is an example of

  • A. Beats.
  • B. Free vibrations.
  • C. Forced vibrations.
  • D. Damped oscillations.

Explanation: The correct answer is beats. When a wooden drum is beaten, it produces sound waves that can slightly differ in frequency, leading to the…

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Correct answer: Beats.

29. When two tuning forks of nearly the same frequencies are sounded together, a note of alternately increasing and decreasing intensity will be heard. This note is called

  • A. Beat.
  • B. Waveform.
  • C. Diffraction.
  • D. Polarisation.

Explanation: The correct answer is beat. When two tuning forks with nearly the same frequencies are sounded together, they produce interference…

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Correct answer: Beat.

30. If two sound waves with frequencies of 128 Hz and 126 Hz are produced simultaneously by two different tunning forks, then the detected beat will have a frequency

  • A. 2 Hz.
  • B. 126 Hz.
  • C. 128 Hz.
  • D. 256 Hz.

Explanation: When two sound waves with close frequencies are played together, they produce beats.

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Correct answer: 2 Hz.

31. All of the following are considered as everyday examples of resonance EXCEPT

  • A. A playground swing
  • B. Shock absorbers of a car.
  • C. Turning the knob of the radio set.
  • D. A music system playing on a heavy beat.

Explanation: The correct answer is Option B: shock absorbers of a car. Shock absorbers are used to dampen or reduce the amplitude of vibrations, not to…

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Correct answer: Shock absorbers of a car.

32. The phenomenon of beats is the result ofI. diffractionII. polarisationIII. interference

  • A. I only.
  • B. III only.
  • C. I and II.
  • D. II and III.

Explanation: The correct answer is III only. Beats occur due to the interference of two waves with slightly different frequencies.

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Correct answer: III only.

33. While performing Young's double slit experiment, the given changes were made. If the initial fringe spacing was 'x', then the fringe spacing after the changes will be

  • A. 4x.
  • B. 2x.
  • C. x / 2.
  • D. x / 4.

Explanation: In Young's double slit experiment, the fringe spacing (Δy) is given by the formula Δy = λL/d, where λ is the wavelength of light, L is the…

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Correct answer: x / 4.

34. In a Newton's ring setup, the MAIN factor responsible for the formation of the rings is

  • A. Reflection of light.
  • B. Refraction of light.
  • C. Diffraction of light.
  • D. Interference of light.

Explanation: The correct answer is interference of light. Newton's rings are formed due to the interference of light waves reflected from the top and…

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Correct answer: Interference of light.

35. Colours reflected from an oil film on water depend on all of the following factors EXCEPT

  • A. Density of oil.
  • B. Angle of view.
  • C. Index of refraction.
  • D. Thickness of the film.

Explanation: The thickness of the film is a critical factor in thin-film interference, which governs the colors reflected from an oil film on water.

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Correct answer: Thickness of the film.

36. The beat frequency of two waves produced by two different tuning forks 505 Hz and 512 Hz will be

  • A. 7 Hz
  • B. 6 Hz.
  • C. 4 Hz.
  • D. 0 Hz.

Explanation: The beat frequency of two waves is the absolute difference between their individual frequencies.Given: * Frequency of the first tuning…

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Correct answer: 7 Hz

37. In Young's Double slit experiment, if the spacing between the slit is doubled and the linear distance from the screen is reduced to one-half then the spacing between the two adjacent bright fringes will be _ of the actual value.

  • A. Remains same.
  • B. Reduce to one half.
  • C. Reduce to one quarter.
  • D. Increase to twice.

Explanation: n=λD/dIf the slit spacing (d) is doubled and the distance between the slit and screen(D) is halved.

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Correct answer: Reduce to one quarter.

38. The path difference for the constructive interference is:

  • A. (n-1)λ
  • B. (n+1)λ
  • C. n λ / 2
  • D. 2n λ
  • E. n λ

Explanation: Option A: (n-1)λ: This is the path difference for destructive interference.

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Correct answer: n λ

39. If displacements due to two individual waves are yl and y2. Then the resultant displacement, y, of the particle of the medium is:

  • A. y = yl * y2
  • B. y = yl / y2
  • C. y = yl - y2
  • D. y = yl + y2

Explanation: When two waves superpose in a medium, the resulting displacement of the particle in the medium is given by the sum of the individual…

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Correct answer: y = yl + y2

40. Two tuning forks produce 6 beats per second. Which of the following are possible frequencies of these tuning forks:

  • A. 12 Hz and 24 Hz
  • B. 8 Hz and 14 Hz
  • C. 10 Hz and 20 Hz
  • D. 66 Hz and 11 Hz

Explanation: Number of beats n= fb-fa [frequencies of tuning forks] So, fb-fa= 6We have to find the option where the difference of two frequencies is…

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Correct answer: 8 Hz and 14 Hz
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