Q.1 Sound waves are classified as which type of wave?
Transverse
Longitudinal
Electromagnetic
Surface
Explanation - Sound waves propagate through compressions and rarefactions in a medium, making them longitudinal in nature.
Correct answer is: Longitudinal
Q.2 What is the typical speed of sound in air at 20°C?
300 m/s
343 m/s
400 m/s
273 m/s
Explanation - At 20°C, the average speed of sound in air is approximately 343 m/s.
Correct answer is: 343 m/s
Q.3 Which property of a medium primarily affects the speed of sound?
Color
Density and elasticity
Temperature only
Pressure
Explanation - The speed of sound depends on both the density and the elasticity of the medium.
Correct answer is: Density and elasticity
Q.4 In which medium does sound travel fastest?
Air
Water
Vacuum
Steel
Explanation - Sound travels fastest in solids due to higher elasticity; steel provides one of the highest speeds.
Correct answer is: Steel
Q.5 Which of the following is necessary for the propagation of sound?
Medium
Vacuum
Magnetic field
Light
Explanation - Sound requires a material medium for propagation as it involves mechanical vibrations.
Correct answer is: Medium
Q.6 The pitch of a sound depends on which parameter?
Amplitude
Frequency
Wavelength
Speed
Explanation - Pitch is the perceptual property of sound related to its frequency.
Correct answer is: Frequency
Q.7 Which unit is used to measure the loudness of sound?
Watt
Hertz
Decibel
Newton
Explanation - Loudness is measured in decibels (dB), a logarithmic unit.
Correct answer is: Decibel
Q.8 What happens to the wavelength of sound when its frequency increases in the same medium?
Wavelength decreases
Wavelength increases
Wavelength remains constant
Speed increases
Explanation - Since v = fλ and speed remains constant in a medium, increasing frequency reduces wavelength.
Correct answer is: Wavelength decreases
Q.9 What is the approximate hearing range of the human ear?
0–500 Hz
20–20000 Hz
200–200000 Hz
2–200 Hz
Explanation - Humans can typically hear frequencies between 20 Hz and 20,000 Hz.
Correct answer is: 20–20000 Hz
Q.10 Ultrasound refers to sound waves of frequency:
Less than 20 Hz
20–20000 Hz
More than 20000 Hz
Infrasonic
Explanation - Ultrasound consists of sound waves with frequencies above 20 kHz.
Correct answer is: More than 20000 Hz
Q.11 Which of these determines the timbre or quality of sound?
Frequency
Overtones
Loudness
Speed
Explanation - The timbre of sound is influenced by the presence of overtones and harmonics.
Correct answer is: Overtones
Q.12 If the amplitude of a sound wave is doubled, what happens to its loudness?
It doubles
It becomes four times
It halves
No change
Explanation - Loudness is proportional to the square of amplitude, so doubling amplitude increases loudness fourfold.
Correct answer is: It becomes four times
Q.13 What is the wavelength of a 170 Hz sound wave in air at 340 m/s?
0.5 m
1 m
2 m
3 m
Explanation - Wavelength λ = v/f = 340 / 170 = 2 m.
Correct answer is: 2 m
Q.14 The reflection of sound is also known as:
Resonance
Echo
Refraction
Diffraction
Explanation - Reflection of sound from a distant surface is perceived as an echo.
Correct answer is: Echo
Q.15 An echo is heard only if the reflecting surface is at least:
5 m away
17 m away
34 m away
50 m away
Explanation - For an echo, the sound must travel 34 m (to and fro) in at least 0.1 s, requiring a distance of ~17 m.
Correct answer is: 17 m away
Q.16 The Doppler effect refers to:
Change in loudness
Change in frequency due to motion
Change in speed
Change in medium
Explanation - Doppler effect describes the apparent change in frequency when source or observer moves relative to the medium.
Correct answer is: Change in frequency due to motion
Q.17 In resonance, maximum energy transfer occurs when:
Driving frequency = natural frequency
Amplitude is zero
Wavelength doubles
Velocity halves
Explanation - Resonance occurs when an external frequency matches the natural frequency, producing large amplitudes.
Correct answer is: Driving frequency = natural frequency
Q.18 Which of the following phenomena demonstrates diffraction of sound?
Hearing around corners
Echo formation
Resonance
Doppler effect
Explanation - Diffraction allows sound waves to bend around obstacles, enabling us to hear around corners.
Correct answer is: Hearing around corners
Q.19 What determines the intensity of a sound wave?
Frequency only
Amplitude only
Square of amplitude
Speed of wave
Explanation - Intensity of sound is proportional to the square of amplitude of vibration.
Correct answer is: Square of amplitude
Q.20 Which part of the ear helps in balancing rather than hearing?
Cochlea
Eardrum
Semicircular canals
Auditory nerve
Explanation - The semicircular canals of the ear help in maintaining balance, not in hearing.
Correct answer is: Semicircular canals
Q.21 Which property of sound allows us to distinguish between two musical instruments playing the same note?
Pitch
Timbre
Loudness
Frequency
Explanation - Timbre is the quality of sound that helps us identify different instruments even at same pitch and loudness.
Correct answer is: Timbre
Q.22 If sound travels at 1500 m/s in water, what is the wavelength of a 500 Hz sound wave?
3 m
15 m
2 m
30 m
Explanation - Wavelength λ = v/f = 1500 / 500 = 3 m.
Correct answer is: 3 m
Q.23 In an open pipe resonator, the fundamental frequency corresponds to:
Half wavelength
Full wavelength
Quarter wavelength
Three-quarter wavelength
Explanation - In an open pipe, the fundamental frequency has a wavelength twice the pipe length (i.e., L = λ/2).
Correct answer is: Half wavelength
Q.24 What is the effect on sound speed when temperature increases?
It decreases
It increases
It remains constant
It becomes zero
Explanation - Speed of sound in gases increases with temperature due to increased kinetic energy of particles.
Correct answer is: It increases
Q.25 The phenomenon used in SONAR is:
Reflection of sound
Refraction of sound
Resonance
Doppler effect
Explanation - SONAR (Sound Navigation and Ranging) is based on the reflection of ultrasonic waves in water.
Correct answer is: Reflection of sound