# Class 9

Explore popular questions from Sound for Class 9. This collection covers Sound previous year Class 9 questions hand picked by experienced teachers.

## Mathematics

Sound

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Q 1. If the speed of an object moving along a straight line keeps changing, its motion is said to be

A

uniform

non-uniform

C

circular

D

None of these

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Q 2. Which of the following relations is correct? distance

A

speed=distance x time

speed = distance {tex} \div {/tex} time

C

speed = distance = time

D

None of these

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Q 3. The basic unit of time is

A

an hour

B

a minute

a second

D

None of these

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Q 4. The symbol of kilometre is

A

kilo

km

C

kilo m

D

None of these

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Q 5. The symbols of all units are written in

A

plural

singular

C

both singular and plural

D

None of these

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Q 6. A speedometre records the speed directly in

A

m/s

B

km/s

km/h

D

m/min

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Q 7. A device that measures the distance by the vehicle is known as

A

a speedometre

an odometer

C

a barometer

D

None of these

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Q 8. Fig shows the distance-time graph for the motion of two vehicles A and B Which one of them is moving faster? {tex}
{/tex}

A

B

B

C

Both A and B are moving with same speed

D

None of these

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Q 9. In humans, sound is produced by

A

Oesophagus

B

Mouth

Larynx

D

Lungs

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Q 10. Sound is produced due to

A

Rotation

B

Gravitation

Vibration

D

Reflection

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Q 11. The sound can not travel through

A

Air

B

Water

Vacuum

D

Oil

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Q 12. The to & fro motion of an object is known as ______motion

A

Rotatory

B

Circular

C

Linear

Oscillatory

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Q 13. If T is the time period & F is the frequency then

T=1{tex} \div {/tex} F

B

F = T{tex}^2{/tex}

C

F = T

D

T = F{tex}^2{/tex}

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Q 14. Unit of frequency is

A

m/s

B

m/s2

C

Kg/m3

hertz

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Q 15. If a body completes 50 oscillations in 1 second, its frequency will be

A

2500 Hz

50 Hz

C

1/50 Hz

D

None

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Q 16. The range of audible frequencies for normal human ear

A

20 Hz to 2000 Hz

B

2 Hz to 20000 Hz

20 Hz to 20000 Hz

D

2 Hz to 2000 Hz

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Q 17. The speed of a wave in a certain medium is 960 m/s. If 3600 waves pass over certain point of the medium in 1 minute then the wavelength of wave is

A

2 metres

B

4 metres

C

8 metres

16 metres

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Q 18. The equation of a progressive wave is Y = a sin (200 t - x) where x and y in metre and t in second. The velocity of wave is:

200 m/sec

B

100 m/sec

C

50 m/sec

D

None of these

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Q 19. Sound waves in air are:

A

Transverse

Longitudinal

C

De-Broglie waves

D

All of these

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Q 20. Sound waves of frequency greater than that of audible sound are called:

A

Sonic sound

B

Seismic waves

C

Infrasonic waves

Ultrasonic waves

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Q 21. Velocity of sound in a gas is 360 msFT{tex}^{-1}{/tex} and the distance between a compression and the nearest rarefraction is 1m. Then the frequency of sound (CPS):

A

90

B

720

180

D

360

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Q 22. In wave motion:

A

Particles of the medium travel from one place to other.

Particles of the medium vibrate about their mean position.

C

Particles of the medium do not vibrate.

D

All are true

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Q 23. Sound waves are:

Longitudinal

B

Transverse

C

None of these

D

Both longitudinal and transverse

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Q 24. The audible frequency range is:

A

20 Hz to 2000 Hz

B

10 Hz to 20 Hz

20 Hz to 20,000 Hz

D

20 Hz to 100 Hz

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Q 25. Assertion: Sound propagates through air from one place to another.Reason: Air particles carry the sound waves from one place to another.

Both Assertion and Reason are true and Reason is the correct explanation of 'Assertion'

B

Both Assertion and Reason are true and Reason is not the correct explanation of 'Assertion'

C

Assertion is true but Reason is false

D

Assertion is false but Reason is true