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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- A. Two times
- B. Three times
- C. Four time
- D. Six time
Explanation: For a gas, sound speed is proportional to 1/√M when the other conditions are comparable.
Correct answer: Four time- A. 281m/sec
- B. 333m/sec
- C. 340m/sec
- D. all of the above
Explanation: Newton used an isothermal model for sound propagation in air and obtained an estimate of about 281 m s-1.
Correct answer: 281m/sec- A. Water
- B. air
- C. copper
- D. ammonia
Explanation: Sound travels fastest in copper because its particles are closely packed and the material has a high elastic modulus, allowing vibrations…
Correct answer: copper- A. 332 ms-1
- B. 320 ms-1
- C. Zero
- D. 224 ms-1
Explanation: Sound is a mechanical wave and requires particles to transmit vibrations, but a vacuum contains no material particles.
Correct answer: Zero- A. adiabatic
- B. isothermal
- C. isobaric
- D. isochoric
Explanation: Newton assumed that the compressions and rarefactions of sound in air occur under isothermal conditions, so heat has time to flow and the…
Correct answer: isothermal- A. λ
- B. λ/2
- C. λ/4
- D. λ/8
Explanation: In a stationary wave, adjacent nodes are separated by half a wavelength, λ/2, and adjacent antinodes are also separated by λ/2.
Correct answer: λ/287. The first overtone of a stretched string of given length is 320 Hz. The first harmonic is_________?
- A. 320 Hz
- B. 640 Hz
- C. 160 Hz
- D. 480 Hz
Explanation: For a stretched string fixed at both ends, the first overtone is the second harmonic, so its frequency is twice the fundamental frequency.
Correct answer: 160 Hz- A. decreases
- B. increases
- C. remains the same
- D. any of above
Explanation: For a stretched wire, the frequency is proportional to the square root of its tension, f = (1/2L)√(T/μ).
Correct answer: increases- A. always an node in formed
- B. always an antinode is formed
- C. neither node nor antinode is formed
- D. sometimes a node and sometimes an antinode is formed
Explanation: At the closed end of an air column, the air cannot move, so the displacement is always zero and a displacement node forms.
Correct answer: always an node in formed- A. antinodes
- B. nodes
- C. troughs
- D. crests
Explanation: In a stationary wave, an antinode is a point where the particles vibrate with maximum amplitude, while a node remains at zero amplitude.
Correct answer: antinodes- A. π
- B. 2π
- C. π/2
- D. π/4
Explanation: Destructive interference occurs when the waves arrive out of phase by an odd multiple of π radians, such as π radians, so their…
Correct answer: π- A. diffraction
- B. dispersion
- C. interference
- D. polarization
Explanation: Colours in a thin film arise from interference between light reflected from the upper and lower surfaces of the film.
Correct answer: interference- A. same wavelength
- B. same amplitude of vibration
- C. same wave length with constant phase difference
- D. same amplitude and wavelength
Explanation: Coherent sources have the same frequency or wavelength and maintain a constant phase difference, which keeps the interference pattern…
Correct answer: same wave length with constant phase difference- A. no interference fringes are observed
- B. no diffraction fringes are observed
- C. no fringes observed
- D. interference pattern not disturbed
Explanation: Double-slit interference requires light from both slits, so covering one slit removes the interference fringes.
Correct answer: no interference fringes are observed- A. bright fringes are wider than dark fringes
- B. dark fringes are wider than bright fringe
- C. both dark and bright fringes are of equal width
- D. central fringes are brighter than the outer fringes
Explanation: For equally spaced interference fringes, the positions of successive bright and dark fringes are equally separated, so their widths are…
Correct answer: both dark and bright fringes are of equal width- A. alternate dark and bright fringes will be seen
- B. coloured fringes will be seen
- C. no interference fringes will be seen
- D. impossible to predict
Explanation: Different colours in white light have different wavelengths, so their bright and dark fringes occur at different positions, producing…
Correct answer: coloured fringes will be seen- A. polarization
- B. constructive interference
- C. destructive interference
- D. diffraction
Explanation: A crest meeting a trough gives displacements in opposite directions, so they cancel partially or completely by destructive interference.
Correct answer: destructive interference- A. interference fringes only
- B. diffraction fringes only
- C. both interference and diffraction fringes
- D. polirized frringes
Explanation: In a real double-slit arrangement, each slit diffracts the light and the waves from the two slits interfere, so interference fringes…
Correct answer: both interference and diffraction fringes- A. 42Hz
- B. 7 Hz
- C. 256Hz
- D. 262Hz
Explanation: Beat frequency is the absolute difference between the frequencies of two close sounds, fbeat = |f1 - f2|.
Correct answer: 7 Hz- A. diffraction of sound waves
- B. constructive and destructive interference
- C. polarization
- D. destructive interference
Explanation: Beats arise when two waves of slightly different frequencies superpose, repeatedly producing constructive interference and destructive…
Correct answer: constructive and destructive interference