Waves and Sound MCQs 2026
50 questions with detailed answers · 22 from past papers · 5 quiz batches available
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- Q1Past Paper · PPSC/FPSC/NTSeasy
Sound waves with frequency above 20,000 Hz are called
💡 Explanation:Waves above the upper limit of human hearing (20 kHz) are termed ultrasonic.
- Q2medium
When a sound source moves towards a stationary observer, the observed frequency
💡 Explanation:As the source approaches, wavefronts bunch up in front of it, increasing the frequency heard by the observer.
- Q3Past Paper · PPSC/FPSC/NTSmedium
The phenomenon in which a body vibrates with maximum amplitude when the frequency of external force matches its natural frequency is called
💡 Explanation:Resonance occurs when the driving frequency equals the natural frequency of the system, producing maximum amplitude.
- Q4Past Paper · PPSC/FPSC/NTSmedium
The periodic variation in loudness of sound heard when two sound waves of slightly different frequencies superpose is called
💡 Explanation:Beats arise from the superposition of two waves of close but different frequencies, producing periodic loudness variation.
- Q5medium
The number of beats produced per second equals
💡 Explanation:Beat frequency is the absolute difference between the two individual frequencies.
- Q6Past Paper · PPSC/FPSC/NTSeasy
A reflected sound heard distinctly after the original sound is called
💡 Explanation:An echo is a distinct repetition of sound caused by reflection, heard after a time gap of at least 0.1 second.
- Q7Past Paper · PPSC/FPSC/NTSeasy
The persistence of sound in a large hall due to multiple reflections is called
💡 Explanation:Reverberation is the continued reflection of sound within an enclosed space, causing it to persist after the source stops.
- Q8hard
The minimum distance required between source and reflecting surface to hear a distinct echo in air is approximately
💡 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.
- Q9Past Paper · PPSC/FPSC/NTSeasy
The loudness of sound depends mainly on its
💡 Explanation:Loudness is directly related to the amplitude (and intensity) of the sound wave.
- Q10Past Paper · PPSC/FPSC/NTSeasy
The pitch of a sound depends mainly on its
💡 Explanation:Pitch, the perceived highness or lowness of a sound, is determined primarily by its frequency.
- Q11medium
The quality or timbre of sound that helps distinguish between two sounds of the same pitch and loudness depends on
💡 Explanation:Timbre depends on the waveform, i.e., the relative strength of overtones present, which differs between instruments or voices.
- Q12Past Paper · PPSC/FPSC/NTSeasy
Loudness of sound is measured in units of
💡 Explanation:Sound intensity level (loudness) is measured on a logarithmic scale in decibels (dB).
- Q13easy
Which of the following is an example of a longitudinal wave
💡 Explanation:Sound waves are longitudinal, with particle vibration parallel to wave propagation, unlike transverse light or water waves.
- Q14easy
A wave produced by plucking a stretched string is an example of
💡 Explanation:When a string is plucked, particles vibrate perpendicular to the wave direction, making it a transverse wave.
- Q15medium
Standing (stationary) waves are produced due to
💡 Explanation:Stationary waves form when two waves of the same frequency and amplitude travel in opposite directions and superpose.
- Q16Past Paper · PPSC/FPSC/NTSeasy
Points of zero displacement in a stationary wave are called
💡 Explanation:Nodes are points of permanent zero displacement in a standing wave pattern.
- Q17easy
Points of maximum displacement in a stationary wave are called
💡 Explanation:Antinodes are points where the amplitude of vibration is maximum in a standing wave.
- Q18medium
The distance between two consecutive nodes (or antinodes) in a stationary wave is
💡 Explanation:Adjacent nodes (or antinodes) in a stationary wave are separated by half a wavelength.
- Q19hard
In an open organ pipe, the fundamental frequency corresponds to a pipe length equal to
💡 Explanation:An open pipe has antinodes at both ends, so the fundamental mode fits half a wavelength into the pipe length.
- Q20hard
In a closed organ pipe (closed at one end), the fundamental frequency corresponds to a pipe length equal to
💡 Explanation:A closed pipe has a node at the closed end and antinode at the open end, so the fundamental fits a quarter wavelength.
- Q21hard
A closed organ pipe produces
💡 Explanation:Closed pipes support only odd harmonics (1st, 3rd, 5th, etc.) due to the boundary conditions at the closed and open ends.
- Q22hard
An open organ pipe produces
💡 Explanation:Open pipes, having antinodes at both ends, support all integral harmonics, both odd and even.
- Q23medium
Overtones that are integral multiples of the fundamental frequency are called
💡 Explanation:Harmonics are frequencies that are whole-number multiples of the fundamental frequency.
- Q24Past Paper · PPSC/FPSC/NTSmedium
The speed of sound is greatest in
💡 Explanation:Sound travels fastest in solids because their particles are closely packed, allowing quicker transmission of vibrations.
- Q25medium
Ultrasonic waves are used in medical diagnostics mainly for
💡 Explanation:Ultrasonic waves reflect off internal tissues at different densities, forming images used in sonography.
- Q26medium
Bats use which phenomenon to navigate and locate prey in the dark
💡 Explanation:Bats emit ultrasonic sound and use the reflected echoes, called echolocation, to detect obstacles and prey.
- Q27easy
The unit used to measure the frequency of a wave is
💡 Explanation:Frequency is measured in hertz (Hz), defined as cycles per second.
- Q28medium
The principle that when two or more waves overlap, the resultant displacement is the sum of individual displacements is called
💡 Explanation:The principle of superposition states the net displacement at a point is the vector sum of displacements due to each wave.
- Q29medium
When sound waves bend around obstacles or through openings, the phenomenon is called
💡 Explanation:Diffraction is the bending of waves around obstacles or through slits comparable in size to their wavelength.
- Q30medium
A sonic boom is produced when an object travels
💡 Explanation:A sonic boom occurs when an object exceeds the speed of sound, creating a shock wave from compressed sound waves.
- Q31Past Paper · PPSC/FPSC/NTSmedium
The ratio of the speed of an object to the speed of sound is called
💡 Explanation:Mach number is defined as the ratio of an object's speed to the local speed of sound.
- Q32medium
Noise pollution is generally considered harmful above sound levels of about
💡 Explanation:Prolonged exposure to sound levels above roughly 85 dB is considered harmful to human hearing.
- Q33medium
Which of the following factors does NOT affect the speed of sound in air
💡 Explanation:Speed of sound in air depends on temperature, humidity and wind, but not on the amplitude (loudness) of the wave.
- Q34medium
The human ear part responsible for converting sound vibrations into nerve impulses is the
💡 Explanation:The cochlea in the inner ear contains hair cells that transduce mechanical vibrations into electrical nerve signals.
- Q35medium
Which musical instrument produces sound primarily through vibrating air columns
💡 Explanation:A flute produces sound by the vibration of an air column inside its tube, unlike stringed instruments like guitar and violin.
- Q36Past Paper · PPSC/FPSC/NTSmedium
As a sound source moves away from a stationary observer, the observed frequency
💡 Explanation:As the source recedes, wavefronts spread out, lowering the observed frequency due to the Doppler effect.
- Q37Past Paper · PPSC/FPSC/NTSmedium
A transmission medium is NOT required for the propagation of
💡 Explanation:Electromagnetic waves, unlike mechanical waves such as sound, can travel through vacuum without any medium.
- Q38Past Paper · PPSC/FPSC/NTSeasy
The type of wave in which particles vibrate perpendicular to the direction of wave propagation is called
💡 Explanation:In transverse waves, particle displacement is perpendicular to the propagation direction, e.g., light and water waves.
- Q39Past Paper · PPSC/FPSC/NTSeasy
Sound waves are classified as
💡 Explanation:In sound waves, particles vibrate parallel to the direction of wave travel via compressions and rarefactions, making them longitudinal.
- Q40easy
The distance between two consecutive compressions or two consecutive rarefactions in a sound wave is called its
💡 Explanation:Wavelength is defined as the distance between two successive points in phase, such as consecutive compressions.
- Q41Past Paper · PPSC/FPSC/NTSmedium
SONAR technology used to detect underwater objects works on the principle of
💡 Explanation:SONAR (Sound Navigation and Ranging) emits ultrasonic waves and detects their reflection off underwater objects to determine distance.
- Q42Past Paper · PPSC/FPSC/NTSeasy
The number of complete oscillations made by a wave in one second is called its
💡 Explanation:Frequency is the number of cycles completed per second, measured in hertz (Hz).
- Q43easy
Sound waves with frequency below 20 Hz are called
💡 Explanation:Frequencies below 20 Hz, inaudible to humans, are called infrasonic waves.
- Q44Past Paper · PPSC/FPSC/NTSmedium
The relationship between wave speed (v), frequency (f) and wavelength (lambda) is given by
💡 Explanation:The universal wave equation states that speed equals frequency multiplied by wavelength.
- Q45Past Paper · PPSC/FPSC/NTSmedium
The speed of sound in air at 0 degree Celsius is approximately
💡 Explanation:At 0 degree Celsius in dry air, sound travels at approximately 332 m/s.
- Q46Past Paper · PPSC/FPSC/NTSmedium
The apparent change in frequency of sound due to relative motion between source and observer is called
💡 Explanation:The Doppler effect describes the change in perceived frequency when a source and observer move relative to each other.
- Q47medium
Sound travels fastest in which of the following media
💡 Explanation:Sound speed is highest in solids like steel due to closely packed particles, far higher than in air or water.
- Q48Past Paper · PPSC/FPSC/NTSeasy
Sound cannot travel through
💡 Explanation:Sound is a mechanical wave and requires a material medium; it cannot propagate through vacuum.
- Q49medium
As the temperature of air increases, the speed of sound
💡 Explanation:Speed of sound increases with temperature because molecules move faster and transmit vibrations more quickly.
- Q50Past Paper · PPSC/FPSC/NTSeasy
The audible range of frequencies for a normal human ear is
💡 Explanation:Normal human hearing range is approximately 20 Hz to 20,000 Hz (20 kHz).