Extra 40 MCQs questions and answers of chapter:12 Sound – Class 9 Science (CBSE):-
Sound is produced due to:
a) Reflection of waves
b) Vibration of objects
c) Refraction of waves
d) Absorption of waves
Ans:
b) Vibration of objects
Which of the following is necessary for sound to propagate?
a) Vacuum
b) Medium
c) High temperature
d) Low pressure
Ans:
b) Medium
Sound waves are:
a) Transverse waves
b) Electromagnetic waves
c) Longitudinal waves
d) Stationary waves
Ans:
c) Longitudinal waves
In which medium does sound travel the fastest?
a) Air
b) Water
c) Solid
d) Vacuum
Ans:
c) Solid
What is the SI unit of frequency?
a) Decibel
b) Hertz
c) Joule
d) Newton
Ans:
b) Hertz
The time taken for one complete vibration of a particle in a medium is called:
a) Frequency
b) Amplitude
c) Time period
d) Wavelength
Ans:
c) Time period
Pitch of a sound depends on:
a) Amplitude
b) Frequency
c) Wavelength
d) Loudness
Ans:
b) Frequency
The speed of sound in air is approximately:
a) 330 m/s
b) 300,000 km/s
c) 1500 m/s
d) 5000 m/s
Ans:
a) 330 m/s
What is the audible range of sound for humans?
a) 0-20 Hz
b) 20 Hz - 20 kHz
c) 20 kHz - 200 kHz
d) Above 200 kHz
Ans:
b) 20 Hz - 20 kHz
Which wave property determines the loudness of sound?
a) Amplitude
b) Frequency
c) Wavelength
d) Speed
Ans:
a) Amplitude
The sound produced by a tuning fork is:
a) Noise
b) Musical sound
c) Both a and b
d) None of the above
Ans:
b) Musical sound
A high-pitched sound has:
a) Low frequency
b) High frequency
c) High amplitude
d) Low amplitude
Ans:
b) High frequency
Which of the following frequencies is ultrasonic?
a) 5 Hz
b) 500 Hz
c) 20 kHz
d) 50 kHz
Ans:
d) 50 kHz
Which of the following instruments produces sound due to vibrations of air columns?
a)
Tabla
b) Guitar
c) Flute
d) Violin
Ans:
c) Flute
Sound waves cannot travel through:
a) Air
b) Water
c) Metal
d) Vacuum
Ans:
d) Vacuum
A sonar system is used to detect objects underwater using:
a) Light waves
b) Infrared waves
c) Ultrasonic waves
d) Radio waves
Ans:
c) Ultrasonic waves
The reflection of sound waves is called:
a) Refraction
b) Echo
c) Diffraction
d) Dispersion
Ans:
b) Echo
The minimum distance required for hearing an echo is:
a) 10 m
b) 17.2 m
c) 20 m
d) 25 m
Ans:
b) 17.2 m
Which part of the human ear helps in collecting sound waves?
a) Cochlea
b) Pinna
c) Eardrum
d) Auditory nerve
Ans:
b) Pinna
The speed of sound is maximum in:
a) Air
b) Water
c) Iron
d) Vacuum
Ans:
c) Iron
Which device uses the principle of multiple reflections of sound?
a) Stethoscope
b) Radio
c) Microscope
d) Telescope
Ans:
a) Stethoscope
The part of the ear that vibrates when sound waves strike it is called:
a) Cochlea
b) Pinna
c) Eardrum
d) Semi-circular canals
Ans:
c) Eardrum
The persistence of sound due to repeated reflection is called:
a) Refraction
b) Resonance
c) Reverberation
d) Diffraction
Ans:
c) Reverberation
What is the full form of SONAR?
a) Sound Navigation and Ranging
b) Sound Noise and Reflection
c) Sound Observation and Resonance
d) Sound Oscillation and Navigation
Ans:
a) Sound Navigation and Ranging
Which property of sound remains unchanged when it travels from one medium to another?
a) Frequency
b) Wavelength
c) Speed
d) Amplitude
Ans:
a) Frequency
What happens when the frequency of a sound wave increases?
a) Loudness increases
b) Pitch increases
c) Amplitude increases
d) Speed increases
Ans:
b) Pitch increases
Why do we hear thunder after seeing lightning?
a) Sound travels faster than light
b) Light travels faster than sound
c) Both travel at the same speed
d) Sound gets absorbed in the air
Ans:
b) Light travels faster than sound
Which part of the human ear sends electrical signals to the brain?
a) Pinna
b) Cochlea
c) Eardrum
d) Auditory nerve
Ans:
d) Auditory nerve
Infrasonic waves have frequencies:
a) Below 20 Hz
b) Between 20 Hz - 20 kHz
c) Above 20 kHz
d) Above 100 kHz
Ans:
a) Below 20 Hz
Which device is used to visualize sound waves?
a) Telescope
b) Microscope
c) Oscilloscope
d) Spectrometer
Ans:
c) Oscilloscope
What is the time period of a wave with a frequency of 50 Hz?
a) 0.02 s
b) 2 s
c) 50 s
d) 0.002 s
Ans:
a) 0.02 s
(T = 1/f = 1/50 = 0.02 s)
What happens to the wavelength if the frequency of a wave is increased?
a) Increases
b) Decreases
c) Remains constant
d) Becomes infinite
Ans:
b) Decreases
What is the velocity of a wave having a frequency of 200 Hz and a wavelength of 2 m?
a) 100 m/s
b) 200 m/s
c) 400 m/s
d) 600 m/s
Ans:
c) 400 m/s
(v = f × λ = 200 × 2 = 400 m/s)
If the speed of sound in air is 340 m/s, what is the wavelength of a sound wave with a frequency of 170 Hz?
a) 2 m
b) 4 m
c) 1 m
d) 0.5 m
Ans:
a) 2 m
(Wavelength = Speed / Frequency = 340 / 170 = 2 m)
What happens to sound intensity if the amplitude of vibration is doubled?
a) Increases 2 times
b) Increases 4 times
c) Decreases 2 times
d) Remains unchanged
Ans:
b) Increases 4 times
The loudness of sound is measured in:
a) Decibel (dB)
b) Hertz (Hz)
c) Joule (J)
d) Newton (N)
Ans:
a) Decibel (dB)
What is the range of ultrasonic waves?
a) Below 20 Hz
b) 20 Hz - 20 kHz
c) Above 20 kHz
d) Above 100 kHz
Ans:
c) Above 20 kHz
Which phenomenon helps bats navigate in the dark?
a) Refraction
b) Echo-location
c) Diffraction
d) Dispersion
Ans:
b) Echo-location
The sound of thunder is heard much later than the flash of lightning due to:
a) Sound being absorbed by air
b) Sound traveling slower than light
c) Reflection of sound
d) Light waves getting refracted
Ans:
b) Sound traveling slower than light
The vibration of which part of a musical instrument produces sound?
a) Air column in a flute
b) Strings in a guitar
c) Membrane in a drum
d) All of the above
Ans:
d) All of the above
