Sound Class 9 Science Multiple Choice Questions & Answers

Question-1. A key of mechanical piano is first struck gently and then struck again but much harder this time. What kind of change in sound will you observe in the second case

1. Sound will be louder but the pitch will be lower
2. Both loudness and pitch will remain unaffected
3. Sound will be louder but the pitch will not be different
4. Sound will be louder and the pitch will also be higher

Question-2. A wave in slinky travelled two and fro in 5 sec the length of the slinky is 5m. What is the velocity of wave?

1. 2m/s
2. 25m/s
3. 10m.s
4. 5m/s

Question-3. Before the main shock waves, the earthquake produces the characteristic sound waves which some animals like rhinoceros can hear. Can you guess the kind of sound waves produced here?

1. Audible Sounds
2. None of these
3. Infrasonic sounds
4. Ultrasonic sounds

Question-4. Compression is a region of

1. Atmospheric pressure
2. High pressure
3. No pressure
4. Low pressure

Question-5. If the speed of a wave is 380 m/s and its frequency is 1900 Hz, then the wavelength of the wave will be

1. 200 m
2. 2 m
3. 20 m
4. 0.2 m

Question-6. If the wave is propagating having the number of waves shown in the figure per second ,then the frequency of the wave is

1. 3Hz
2. 10Hz
3. 5Hz
4. 6Hz

Question-7. In gases a sound wave is

1. Both Transverse and Longitudinal
2. Neither Transverse Nor Longitudinal
3. Longitudinal only
4. Transverse only

Question-8. Pitch of the wave is measured in terms of

1. Frequency of the wave
2. Time period of the wave
3. Speed of the wave
4. Amplitude of the wave

Question-9. SI unit of frequency is

1. M/s
2. M/s2
3. Meter
4. Hertz

Question-10. Sound waves are

1. Transverse
2. Sometimes longitudinal, sometimes transverse
3. Longitudinal
4. Partly longitudinal, partly transverse

Question-11. Sound waves with frequency less than 20 Hz and more than 20000 Hz is called

1. Infrasonic and sonic boom
2. Infrasonic and ultrasonic
3. Supersonic and ultrasonic
4. Sonic boom and supersonic

Question-12. Speed of sound depends upon

1. Temperature of source producing sound
2. Temperature and pressure of medium
3. Temperature of the medium
4. Pressure of the medium

Question-13. Speed of sound in vacuum is

1. 380m/s
2. 340m/s
3. 300 m/s
4. 600m/s

Question-14. The bats can fly in the darkness of night without colliding with the other objects by emitting special sounds while flying. Which characteristic of sound is used by the bats to navigate?

1. Audible sound
2. None of these
3. Ultrasound
4. Infrasound

Question-15. The characteristic of sound which enables us to distinguish one sound from another having the same pitch and loudness

1. Shrillness
2. Intensity
3. Timber
4. Amplitude

Question-16. The distance between any two compressions or rarefactions in a longitudinal wave is

1. Twice the wavelength
2. One fourth wavelength
3. One wavelength
4. Half wavelength

Question-17. The sound can travel in air when

1. Disturbance travel from one place to another
2. Both particles as well as disturbance travel from one place to another
3. Particles of medium travel from one place to another
4. There is no moisture in the atmosphere

Question-18. The sound which is produced due to a mixture of several frequencies is called

1. Frequency
2. Amplitude
3. A note
4. A tone

Question-19. The time period of a simple pendulum in a spacecraft orbiting the earth is

1. One second
2. Two seconds
3. Infinity
4. Zero

Question-20. We can distinguish between a man?s voice and a woman?s voice of the same loudness even without seeing them. This is due to a characteristic of sound which measures the shrillness of sounds. Can you choose the correct unit of the quantity on which this characteristic of sound depends?

1. meter
2. unitless
3. hertz
4. meter/second

Question-21. What do dolphins, bats and porpoise use

1. Both a and b
2. None of them
3. Ultrasound
4. Infrasound

Question-22. Which of the following can produce longitudinal as well as transverse waves under different conditions?

1. Tuning fork
2. None of these
3. Bats
4. Slinky

Question-23. You must have seen the doctor checking the sounds produced in the chest or heartbeat of a patient using a medical instrument called Stethoscope. On what principle does this Stethoscope work?

1. Wave motion
2. None of these
3. Multiple refractions
4. Multiple reflections