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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1,281 questions · page 37 of 65
- A. 0.5 m
- B. 1.01 m
- C. 1.5 m
- D. 2.0 m
Explanation: Wavelength λ = v / f = 343 / 340 ≈ 1.01 m, which is the distance between consecutive crests.
Correct answer: 1.01 m- A. 375 Hz
- B. 400 Hz
- C. 425 Hz
- D. 450 Hz
Explanation: Doppler effect: f' = f × (v / (v - vs )) = 400 × (343 / (343 - 20)) = 400 × (343 / 323) ≈ 425 Hz.
Correct answer: 425 Hz- A. 0 W/m²
- B. 2 W/m²
- C. 4 W/m²
- D. 8 W/m²
Explanation: Destructive interference of equal amplitude waves results in zero amplitude, so the resultant intensity is 0 W/m².
Correct answer: 0 W/m²- A. 37.5 Hz
- B. 75 Hz
- C. 112.5 Hz
- D. 150 Hz
Explanation: For a string fixed at both ends, nth harmonic frequency fn = (n × v) / (2L).
Correct answer: 112.5 Hz- A. 2.5 × 10⁻⁵ W/m²
- B. 5.0 × 10⁻⁵ W/m²
- C. 1.0 × 10⁻⁴ W/m²
- D. 4.0 × 10⁻⁴ W/m²
Explanation: Intensity follows the inverse square law: I2 = I1 × (r1 / r2 )² = 10⁻⁴ × (2 / 4)² = 10⁻⁴ × 0.25 = 2.5 × 10⁻⁵ W/m².
Correct answer: 2.5 × 10⁻⁵ W/m²- A. 101 Hz
- B. 202 Hz
- C. 303 Hz
- D. 404 Hz
Explanation: For an open pipe, fundamental frequency f1 = v / (2L) = 343 / (2 × 0.85) = 343 / 1.7 ≈ 202 Hz.
Correct answer: 202 Hz- A. 5 Hz
- B. 10 Hz
- C. 15 Hz
- D. 20 Hz
Explanation: Beat frequency = |f1 - f2 | = |510 - 500| = 10 Hz.
Correct answer: 10 Hz- A. 368 Hz
- B. 400 Hz
- C. 436 Hz
- D. 472 Hz
Explanation: Explanation: Doppler effect: f' = f × (v / (v - vs )) = 400 × (343 / (343 - 30)) = 400 × (343 / 313) ≈ 436 Hz.
Correct answer: 436 Hz- A. 0.67 m
- B. 1.0 m
- C. 1.33 m
- D. 2.0 m
Explanation: For a closed pipe, second harmonic wavelength λ2 = 4L / 3 = (4 × 0.5) / 3 = 2 / 3 ≈ 1.33 m.
Correct answer: 1.33 m- A. Ultrasonic
- B. Amplitude
- C. Echo location
- D. Refraction
Explanation: Bats emit ultrasonic pulses and interpret returning echoes (echolocation) to determine distance, direction and nature of objects, so…
Correct answer: Echo location- A. White shift
- B. Neutron stars
- C. Black holes
- D. Red shift
Explanation: Observed cosmological redshift of galaxy spectra shows systematic wavelength stretching indicative of recession and cosmic expansion, so…
Correct answer: Red shift- A. Heating
- B. Resonance
- C. Reverberation
- D. Damping
Explanation: Resonance describes the phenomenon of increased amplitude that occurs when the frequency of a periodically applied force is equal or close…
Correct answer: Resonance- A. |fa - fb|
- B. |fa ÷ fb|
- C. |fa x fb|
- D. |fa + fb|
Explanation: The beat frequency is the difference in frequency between two interacting waves.
Correct answer: |fa - fb|- A. 984 Hz
- B. 1000 Hz
- C. 1008 Hz
- D. 1210 Hz
Explanation: Frequency = 1000 HzSpeed of ship = 10 km/h = 2.78 m/sSonic signal speed = 340 m/sApparent frequency is found as:f' = vsound / (vsound -…
Correct answer: 1008 Hz- A. 17 Hz
- B. 34 Hz
- C. 68 Hz
- D. 306 Hz
Explanation: In the second harmonic frequency of the sound in an open tube, the wavelength is 1 lambda (as shown in the figure below; the distance of…
Correct answer: 68 Hz- A. Quality ... Pitch ... Loudness ... Pitch
- B. Pitch ... Pitch ... Pitch ... Pitch
- C. Loudness ... Quality ... Pitch ... Quality
- D. Quality ... Quality ... Quality ... Quality
- E. Loudness ... Loudness ... Loudness ... Loudness
Explanation: The quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone is generally called…
Correct answer: Pitch ... Pitch ... Pitch ... Pitch- A. I only
- B. III only
- C. I and II only
- D. II and III only
- E. I, II and III
Explanation: If the two sounds have the same wavelength in air at the same temperature, it means they have the same speed of propagation in that…
Correct answer: III only- A. 1.12 m
- B. 300 m
- C. 330 m
- D. 112 m
- E. 11201 m
Explanation: We are given thatfrequency=300Hz, and velocity v=336ms−1From the relation v=f×λ,λ=v/f=336/300=1.12mOption "A" is correct.
Correct answer: 1.12 m- A. The thickest string
- B. The thinnest string
- C. The wave speed is the same on all the strings
- D. None of the above
Explanation: The velocity of a transverse wave in a stretched string is given by: v = √(T/n).
Correct answer: The thinnest string- A. 2
- B. 3
- C. 0
- D. 1
Explanation: The product of frequency and time is equal to 1 according to the formula f=1/T where f represents the frequency having the units…
Correct answer: 1