Sound – MCQs – Online Practice Test with Automatic scoring
CBSE Class 9
Physics — Chapter 12: Sound
30-question timed quiz — 30 minutes | Auto-scoring & instant per-question feedback (NCERT-aligned)
Q1
Basics
Sound in air is an example of a:
Correct:
Q2
Wave relation
Which relation is correct for wave speed v, frequency f and wavelength λ?
Correct:
Q3
Units
The SI unit of frequency is:
Correct:
Q4
Basics
Wavelength (λ) of a sound wave is the:
Correct:
Q5
Characteristics
Which property mainly determines the pitch of a sound?
Correct:
Q6
Characteristics
Loudness of a sound is most closely related to its:
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Q7
Propagation
Which of the following cannot transmit sound?
Correct:
Q8
Speed & Temperature
Approximate speed of sound in air at 20 °C is:
Correct:
Q9
Wave relation
If frequency of a sound doubles while speed remains same, the wavelength will:
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Q10
Human Hearing
Typical audible frequency range for humans is approximately:
Correct:
Q11
Reflection & Echo
Minimum time delay (approx.) for a reflected sound to be heard as an echo is:
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Q12
Reflection
Law of reflection for sound states:
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Q13
Reverberation
Excessive reverberation in a hall mainly causes:
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Q14
Acoustics
To reduce reverberation in a lecture hall you should:
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Q15
Intensity
For a point sound source, intensity approximately varies with distance r as:
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Q16
Beats
Two tuning forks of 256 Hz and 259 Hz produce beats at frequency:
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Q17
Doppler
An ambulance siren sounds higher in pitch as it approaches because:
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Q18
Ultrasound
Ultrasonic sound has frequency:
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Q19
Infrasound
Infrasonic waves have frequency:
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Q20
Propagation
Which sound will travel farther outdoors with less attenuation?
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Q21
Human Ear
Which part of the ear converts vibrations into electrical impulses?
Correct:
Q22
Hearing
Threshold of hearing corresponds to intensity approximately:
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Q23
Safety
Prolonged exposure to sounds above approximately which level is hazardous?
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Q24
Applications
Sonar determines distance to an object by measuring:
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Q25
Resonance
Resonance occurs when a system is driven at:
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Q26
Diffraction
Diffraction of sound is most noticeable when the obstacle size is:
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Q27
Timbre
Which factor mainly gives an instrument its unique timbre?
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Q28
Ultrasound
In medical ultrasound, increasing frequency typically:
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Q29
Impedance
A large reflection of sound at an interface occurs when:
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Q30
Safety
Which is the best immediate protective measure for workers in a noisy factory?
Correct: