Waves and Sound MCQs 2026

50 questions with detailed answers · 22 from past papers · 5 quiz batches available

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Page 1 of 1 Questions 1–10 of 50

Q1 Past Paper · PPSC/FPSC/NTS medium

The periodic variation in loudness of sound heard when two sound waves of slightly different frequencies superpose is called
1. A Resonance
2. B Echo
3. C Beats
4. D Doppler effect
💡 Explanation:
Beats arise from the superposition of two waves of close but different frequencies, producing periodic loudness variation.
Q2 Past Paper · PPSC/FPSC/NTS medium

SONAR technology used to detect underwater objects works on the principle of
1. A Reflection of ultrasonic waves
2. B Refraction of light
3. C Diffraction of sound
4. D Polarization
💡 Explanation:
SONAR (Sound Navigation and Ranging) emits ultrasonic waves and detects their reflection off underwater objects to determine distance.
Q3 Past Paper · PPSC/FPSC/NTS medium

The apparent change in frequency of sound due to relative motion between source and observer is called
1. A Resonance
2. B Doppler effect
3. C Interference
4. D Reflection
💡 Explanation:
The Doppler effect describes the change in perceived frequency when a source and observer move relative to each other.
Q4 Past Paper · PPSC/FPSC/NTS medium

A transmission medium is NOT required for the propagation of
1. A Sound waves
2. B Electromagnetic waves
3. C Water waves
4. D Waves on a string
💡 Explanation:
Electromagnetic waves, unlike mechanical waves such as sound, can travel through vacuum without any medium.
Q5 Past Paper · PPSC/FPSC/NTS medium

As a sound source moves away from a stationary observer, the observed frequency
1. A Increases
2. B Remains constant
3. C Doubles
4. D Decreases
💡 Explanation:
As the source recedes, wavefronts spread out, lowering the observed frequency due to the Doppler effect.
Q6 medium

Which musical instrument produces sound primarily through vibrating air columns
1. A Guitar
2. B Violin
3. C Flute
4. D Drum
💡 Explanation:
A flute produces sound by the vibration of an air column inside its tube, unlike stringed instruments like guitar and violin.
Q7 medium

The human ear part responsible for converting sound vibrations into nerve impulses is the
1. A Eardrum
2. B Ossicles
3. C Auditory canal
4. D Cochlea
💡 Explanation:
The cochlea in the inner ear contains hair cells that transduce mechanical vibrations into electrical nerve signals.
Q8 medium

Which of the following factors does NOT affect the speed of sound in air
1. A Temperature
2. B Humidity
3. C Wind direction
4. D Amplitude of the wave
💡 Explanation:
Speed of sound in air depends on temperature, humidity and wind, but not on the amplitude (loudness) of the wave.
Q9 medium

Noise pollution is generally considered harmful above sound levels of about
1. A 20 dB
2. B 40 dB
3. C 85 dB
4. D 200 dB
💡 Explanation:
Prolonged exposure to sound levels above roughly 85 dB is considered harmful to human hearing.
Q10 Past Paper · PPSC/FPSC/NTS medium

The ratio of the speed of an object to the speed of sound is called
1. A Doppler number
2. B Beat frequency ratio
3. C Mach number
4. D Resonance ratio
💡 Explanation:
Mach number is defined as the ratio of an object's speed to the local speed of sound.
Q11 medium

A sonic boom is produced when an object travels
1. A At the speed of sound
2. B Faster than the speed of sound
3. C Slower than the speed of sound
4. D At rest
💡 Explanation:
A sonic boom occurs when an object exceeds the speed of sound, creating a shock wave from compressed sound waves.
Q12 medium

When sound waves bend around obstacles or through openings, the phenomenon is called
1. A Diffraction
2. B Reflection
3. C Polarization
4. D Dispersion
💡 Explanation:
Diffraction is the bending of waves around obstacles or through slits comparable in size to their wavelength.
Q13 medium

The principle that when two or more waves overlap, the resultant displacement is the sum of individual displacements is called
1. A Reflection
2. B Refraction
3. C Diffraction
4. D Principle of superposition
💡 Explanation:
The principle of superposition states the net displacement at a point is the vector sum of displacements due to each wave.
Q14 easy

The unit used to measure the frequency of a wave is
1. A Meter
2. B Second
3. C Hertz
4. D Newton
💡 Explanation:
Frequency is measured in hertz (Hz), defined as cycles per second.
Q15 medium

Bats use which phenomenon to navigate and locate prey in the dark
1. A Echolocation using ultrasonic waves
2. B Doppler effect of light
3. C Reverberation
4. D Resonance
💡 Explanation:
Bats emit ultrasonic sound and use the reflected echoes, called echolocation, to detect obstacles and prey.
Q16 medium

Ultrasonic waves are used in medical diagnostics mainly for
1. A X-ray imaging
2. B Ultrasound imaging (sonography)
3. C MRI scanning
4. D CT scanning
💡 Explanation:
Ultrasonic waves reflect off internal tissues at different densities, forming images used in sonography.
Q17 Past Paper · PPSC/FPSC/NTS medium

The speed of sound is greatest in
1. A Gases
2. B Solids
3. C Liquids
4. D Vacuum
💡 Explanation:
Sound travels fastest in solids because their particles are closely packed, allowing quicker transmission of vibrations.
Q18 medium

Overtones that are integral multiples of the fundamental frequency are called
1. A Harmonics
2. B Beats
3. C Resonant tones
4. D Echoes
💡 Explanation:
Harmonics are frequencies that are whole-number multiples of the fundamental frequency.
Q19 hard

An open organ pipe produces
1. A Only odd harmonics
2. B Both odd and even harmonics
3. C Only even harmonics
4. D No harmonics
💡 Explanation:
Open pipes, having antinodes at both ends, support all integral harmonics, both odd and even.
Q20 hard

A closed organ pipe produces
1. A All harmonics
2. B Only odd harmonics
3. C Only even harmonics
4. D No harmonics
💡 Explanation:
Closed pipes support only odd harmonics (1st, 3rd, 5th, etc.) due to the boundary conditions at the closed and open ends.
Q21 hard

In a closed organ pipe (closed at one end), the fundamental frequency corresponds to a pipe length equal to
1. A One-fourth of the wavelength
2. B Half the wavelength
3. C One full wavelength
4. D Two wavelengths
💡 Explanation:
A closed pipe has a node at the closed end and antinode at the open end, so the fundamental fits a quarter wavelength.
Q22 hard

In an open organ pipe, the fundamental frequency corresponds to a pipe length equal to
1. A Half the wavelength
2. B One wavelength
3. C A quarter wavelength
4. D Twice the wavelength
💡 Explanation:
An open pipe has antinodes at both ends, so the fundamental mode fits half a wavelength into the pipe length.
Q23 medium

The distance between two consecutive nodes (or antinodes) in a stationary wave is
1. A One full wavelength
2. B One-fourth wavelength
3. C Half wavelength
4. D Two wavelengths
💡 Explanation:
Adjacent nodes (or antinodes) in a stationary wave are separated by half a wavelength.
Q24 easy

Points of maximum displacement in a stationary wave are called
1. A Nodes
2. B Troughs
3. C Antinodes
4. D Crests only
💡 Explanation:
Antinodes are points where the amplitude of vibration is maximum in a standing wave.
Q25 Past Paper · PPSC/FPSC/NTS easy

Points of zero displacement in a stationary wave are called
1. A Nodes
2. B Antinodes
3. C Crests
4. D Troughs
💡 Explanation:
Nodes are points of permanent zero displacement in a standing wave pattern.
Q26 medium

Standing (stationary) waves are produced due to
1. A Superposition of two identical waves traveling in opposite directions
2. B A single wave traveling in one direction
3. C Refraction of a wave
4. D Diffraction of a wave
💡 Explanation:
Stationary waves form when two waves of the same frequency and amplitude travel in opposite directions and superpose.
Q27 easy

A wave produced by plucking a stretched string is an example of
1. A Longitudinal wave
2. B Transverse wave
3. C Electromagnetic wave
4. D Stationary wave only
💡 Explanation:
When a string is plucked, particles vibrate perpendicular to the wave direction, making it a transverse wave.
Q28 easy

Which of the following is an example of a longitudinal wave
1. A Light wave
2. B Water wave
3. C Wave on a string
4. D Sound wave
💡 Explanation:
Sound waves are longitudinal, with particle vibration parallel to wave propagation, unlike transverse light or water waves.
Q29 Past Paper · PPSC/FPSC/NTS easy

Loudness of sound is measured in units of
1. A Hertz
2. B Newton
3. C Watt
4. D Decibel
💡 Explanation:
Sound intensity level (loudness) is measured on a logarithmic scale in decibels (dB).
Q30 medium

The quality or timbre of sound that helps distinguish between two sounds of the same pitch and loudness depends on
1. A Amplitude
2. B Frequency
3. C Speed
4. D Waveform
💡 Explanation:
Timbre depends on the waveform, i.e., the relative strength of overtones present, which differs between instruments or voices.
Q31 Past Paper · PPSC/FPSC/NTS easy

The pitch of a sound depends mainly on its
1. A Amplitude
2. B Waveform
3. C Frequency
4. D Speed
💡 Explanation:
Pitch, the perceived highness or lowness of a sound, is determined primarily by its frequency.
Q32 Past Paper · PPSC/FPSC/NTS easy

The loudness of sound depends mainly on its
1. A Amplitude
2. B Wavelength
3. C Frequency
4. D Speed
💡 Explanation:
Loudness is directly related to the amplitude (and intensity) of the sound wave.
Q33 hard

The minimum distance required between source and reflecting surface to hear a distinct echo in air is approximately
1. A 1.7 m
2. B 5 m
3. C 17.2 m
4. D 100 m
💡 Explanation:
Given sound speed about 344 m/s and the minimum 0.1 s time gap needed for the ear to distinguish sounds, minimum distance is about 17.2 m.
Q34 Past Paper · PPSC/FPSC/NTS easy

The persistence of sound in a large hall due to multiple reflections is called
1. A Reverberation
2. B Echo
3. C Resonance
4. D Refraction
💡 Explanation:
Reverberation is the continued reflection of sound within an enclosed space, causing it to persist after the source stops.
Q35 Past Paper · PPSC/FPSC/NTS easy

A reflected sound heard distinctly after the original sound is called
1. A Reverberation
2. B Resonance
3. C Echo
4. D Beats
💡 Explanation:
An echo is a distinct repetition of sound caused by reflection, heard after a time gap of at least 0.1 second.
Q36 medium

The number of beats produced per second equals
1. A The sum of the two frequencies
2. B The product of the two frequencies
3. C The average of the two frequencies
4. D The difference of the two frequencies
💡 Explanation:
Beat frequency is the absolute difference between the two individual frequencies.
Q37 easy

Sound waves with frequency below 20 Hz are called
1. A Ultrasonic waves
2. B Infrasonic waves
3. C Audible waves
4. D Supersonic waves
💡 Explanation:
Frequencies below 20 Hz, inaudible to humans, are called infrasonic waves.
Q38 Past Paper · PPSC/FPSC/NTS medium

The phenomenon in which a body vibrates with maximum amplitude when the frequency of external force matches its natural frequency is called
1. A Interference
2. B Resonance
3. C Diffraction
4. D Beats
💡 Explanation:
Resonance occurs when the driving frequency equals the natural frequency of the system, producing maximum amplitude.
Q39 medium

When a sound source moves towards a stationary observer, the observed frequency
1. A Decreases
2. B Remains the same
3. C Increases
4. D Becomes zero
💡 Explanation:
As the source approaches, wavefronts bunch up in front of it, increasing the frequency heard by the observer.
Q40 Past Paper · PPSC/FPSC/NTS easy

The type of wave in which particles vibrate perpendicular to the direction of wave propagation is called
1. A Longitudinal wave
2. B Mechanical wave
3. C Stationary wave
4. D Transverse wave
💡 Explanation:
In transverse waves, particle displacement is perpendicular to the propagation direction, e.g., light and water waves.
Q41 Past Paper · PPSC/FPSC/NTS easy

Sound waves are classified as
1. A Transverse waves
2. B Electromagnetic waves
3. C Standing waves only
4. D Longitudinal waves
💡 Explanation:
In sound waves, particles vibrate parallel to the direction of wave travel via compressions and rarefactions, making them longitudinal.
Q42 easy

The distance between two consecutive compressions or two consecutive rarefactions in a sound wave is called its
1. A Amplitude
2. B Frequency
3. C Wavelength
4. D Time period
💡 Explanation:
Wavelength is defined as the distance between two successive points in phase, such as consecutive compressions.
Q43 Past Paper · PPSC/FPSC/NTS easy

The number of complete oscillations made by a wave in one second is called its
1. A Amplitude
2. B Frequency
3. C Wavelength
4. D Time period
💡 Explanation:
Frequency is the number of cycles completed per second, measured in hertz (Hz).
Q44 Past Paper · PPSC/FPSC/NTS medium

The relationship between wave speed (v), frequency (f) and wavelength (lambda) is given by
1. A v = f divided by lambda
2. B v = f minus lambda
3. C v = f plus lambda
4. D v = f multiplied by lambda
💡 Explanation:
The universal wave equation states that speed equals frequency multiplied by wavelength.
Q45 Past Paper · PPSC/FPSC/NTS medium

The speed of sound in air at 0 degree Celsius is approximately
1. A 332 m/s
2. B 500 m/s
3. C 150 m/s
4. D 1500 m/s
💡 Explanation:
At 0 degree Celsius in dry air, sound travels at approximately 332 m/s.
Q46 medium

Sound travels fastest in which of the following media
1. A Steel
2. B Air
3. C Water
4. D Vacuum
💡 Explanation:
Sound speed is highest in solids like steel due to closely packed particles, far higher than in air or water.
Q47 Past Paper · PPSC/FPSC/NTS easy

Sound cannot travel through
1. A Water
2. B Vacuum
3. C Steel
4. D Air
💡 Explanation:
Sound is a mechanical wave and requires a material medium; it cannot propagate through vacuum.
Q48 medium

As the temperature of air increases, the speed of sound
1. A Increases
2. B Decreases
3. C Remains constant
4. D Becomes zero
💡 Explanation:
Speed of sound increases with temperature because molecules move faster and transmit vibrations more quickly.
Q49 Past Paper · PPSC/FPSC/NTS easy

The audible range of frequencies for a normal human ear is
1. A 2 Hz to 200 Hz
2. B 200 Hz to 2000 Hz
3. C 20000 Hz to 200000 Hz
4. D 20 Hz to 20000 Hz
💡 Explanation:
Normal human hearing range is approximately 20 Hz to 20,000 Hz (20 kHz).
Q50 Past Paper · PPSC/FPSC/NTS easy

Sound waves with frequency above 20,000 Hz are called
1. A Infrasonic waves
2. B Ultrasonic waves
3. C Audible waves
4. D Radio waves
💡 Explanation:
Waves above the upper limit of human hearing (20 kHz) are termed ultrasonic.

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Waves and Sound MCQs 2026

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