## Class 9 Science Objective Chapter – 12 Sound

Here we are providing Class 9 Science Objective Chapter – 12 Sound because its very important for Class 9 students as we all know that every board exam question has MCQs so that students should practice these questions so that students can get good marks in board. Class 9 Science Objective Chapter – 12 Sound is an extremely important and its also a year in which students learn the fundamentals of concepts that help them lay a solid foundation for their higher education. Here we are providing in Class Class 9 Science Objective Chapter – 12 Sound 100+ questions  so that students practice more and more. If you want class wise Notes Then Click Here

Class 9 Science Objective Chapter – 12 Sound

1. Before playing the orchestra in a musical concert, a sitarist tries to adjust the tension and pluck the string suitably. By doing so, he is adjusting

( A ) intensity of sound only

( B ) amplitude of sound only

( C ) frequency of the sitar string with the frequency of other musical instruments

( D ) loudness of sound

Ans – ( C )

2. The distance between a consecutive crest and trough is x. The wavelength of the wave is

( A ) 4x

( B ) x

( C ) x/2

( D ) 2x

Ans – ( D )

3. Sound can be transferred through

( A ) Solid

( B ) Liquid

( C ) Gases

( D ) All of these

Ans – ( D )

4. 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?

( A ) Infrasonic sounds

( B ) Ultrasonic sounds

( C ) Audible Sounds

( D ) None of these

Ans – ( A )

5. Sound wave is a

( A ) transverse wave

( B ) longitudinal wave

( C ) both a and b

( D ) None of these

Ans – ( A )

6. The SI unit of frequency is —

( A ) Hertz

( B ) Per second

( C ) Meter/ second

( D ) Both a) and b)

Ans – ( D )

7. When we change feeble sound to loud sound we increase its

( A ) frequency

( B ) amplitude

( C ) velocity

( D ) wavelength

Ans – ( B )

8. You can not talk to each other on the moon because

( A ) atmosphere is not present, that is, there is vacuum

( B ) you would not feel like talking

( C ) compressions and rarefactions can only travel on earth’s surface

( D ) gravity is 1/6th that on the earth

Ans – ( A )

9. Loudness or softness of a sound is depend on

( A ) Amplitude

( B ) Frequency

( C ) Type of a wave

( D ) None of these

Ans – ( A )

10. Sound waves are

( A ) magnetic waves

( B ) electric waves

( C ) electromagnetic waves

( D ) mechanical waves

Ans – ( D )

11. Sonic booms are caused by the combination of

( A ) supersonic speed and pressure variation.

( B ) infrasonic speed and pressure variation.

( C ) ultrasonic sound and pressure variation.

( D ) pressure variation only.

Ans – ( A )

12. Amplitude of the wave is depend on

( A ) Nature of wave

( B ) Force with which an object is made tovibrate

( C ) Displacement of the sound wave

( D ) Frequency of a wave

Ans – ( B )

13. In longitudinal waves, how does the particle of medium vibrate compared to the direction of propagation of wave?

( A ) Perpendicular

( B ) Parallel

( C ) At 45°

( D ) At 60°

Ans – ( B )

14. Note is a sound

( A ) of mixture of several frequencies

( B ) of mixture of two frequencies only

( C ) of a single frequency

( D ) always unpleasant to listen

Ans – ( C )

15. The sound waves in a medium are characterised by the

( A ) Linear motion of particles in the medium

( B ) Rotatory motion of particles in the medium

( C ) Oscillatory motion of particles in the medium

( D ) None of the above

Ans – ( C )

16.The speed of sound is greater in

( A ) Nickel

( B ) Ethanol

( C ) Air

( D ) Sulphur dioxide

Ans – ( A )

17. The sound can travel in air when

( A ) Particles of medium travel from one place to another

( B ) There is no moisture in the atmosphere

( C ) Disturbance travel from one place to another

( D ) Both particles as well as disturbance travel from one place to another

Ans – ( C )

18. Sound can travel through

( A ) gases only

( B ) vacuum only

( C ) gases and liquids only

( D ) solids, liquids and gases.

Ans – ( D )

19. Horns of the vehicles are based on the principle of

( A ) Echo

( B ) Multiple reflections of sound

( C ) Ultrasound waves

( D ) None of these

Ans – ( B )

20. A key of a mechanical piano struck gently and then struck again but mush harder this time. In the second case

( A ) sound will be louder but pitch will not be different

( B ) sound will be louder and pitch will also be higher

( C ) sound will be louder but pitch will be lower

( D ) both loudness and pitch will remain unaffected

Ans – ( A )

21. Children under age of 5 years can hear sound upto

( A ) 10 kHz

( B ) 20 2Hz

( C ) 25 kHz

( D ) 30 kHz

Ans – ( C )

22. The motion of the particles of a medium when a sound wave is passing through it is

( A ) translatory

( B ) random

( C ) rotatory

( D ) oscillatory

Ans – ( D )

23. For hearing a distinct sound, the time interval between the original sound and the reflected one must be at least

( A ) 1 s

( B ) 0.1 s

( C ) 2 s

( D ) 0.2 s

Ans – ( B )

24. Rhinoceroses communicate using

( A ) Ultrasound waves

( B ) Infrasound waves

( C ) Audible sound waves

( D ) All of the above

Ans – ( B )

25.The persistence of sound in an auditorium is the result of repeated reflections of sound and is called

( A ) reverberation

( B ) audible

( C ) distinct sound

( D ) reflection

Ans – ( A )

26. 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?

( A ) hertz

( B ) meter/second

( C ) meter

( D ) unitless

Ans – ( A )

27. The frequency of ultrasound waves is

( A ) Less than audible sound waves

( B ) Greater than audible sound waves

( C ) Equal to or less than sound waves

( D ) None of these

Ans – ( B )

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

( A ) Bats

( B ) Slinky

( C ) Tuning fork

( D ) None of these

Ans – ( B )

29. If the pendulum oscillate 78 times in one minute then the frequency of that pendulum will be—

( A ) 2 Hz

( B ) 1.5 Hz

( C ) 1.3 Hz

( D ) 1.2 Hz

Ans – ( C )

30. Infrasound can be heard by

( A ) dog

( B ) bat

( C ) rhinoceros

( D ) human beings

Ans – ( C )

31. The speed v, frequency υ, and wavelength λ, of sound are related by the equation

( A ) v = λυ

( B ) υ = λv

( C ) λ = υv

( D ) v = λ\υ

Ans – ( A )

32. An earthquake produces which kind of sound before the mainshock wave begins

( A ) ultrasound

( B ) infrasound

( C ) audible sound

( D ) None of the above

Ans – ( b )

33.Which of the following is carried by the waves from one place to another

( A ) Velocity

( B ) Work

( C ) Energy

( D ) Mass

Ans – ( C )

34. The upper frequency limit of the audible range of human hearing is about

( A ) 20 kHz

( B ) 2000 Hz

( C ) 2 kHz

( D ) 2,000,000 Hz

Ans – ( A )

35. Earthquake produces which kind of sound before the main shock wave begins

( A ) ultrasound

( B ) infrasound

( C ) audible sound

( D ) none of the above

Ans – ( A )

36. In gases a sound wave is

( A ) Longitudinal only

( B ) Transverse only

( C ) both A and B

( D ) None of these

Ans – ( A )

37. Which of the following vibrates when a musical note is produced by the cymbals in an orchestra ?

( A ) stretched strings

( B ) stretched membranes

( C ) metal plates

( D ) air columns

Ans – ( C )

38. The speed of sound is maximum in

( A ) solids

( B ) liquids

( C ) gases

( D ) All of these

Ans – ( a )

39. A body produces sound only if it is

( A ) Made of glass

( B ) Made of aluminium

( C ) Vibration

( D ) Made of iron

Ans – ( C )

40. The frequency of sound waves can be expressed in

( A ) Second

( B ) Cycle

( C ) Metre per second

( D ) Cycle per second

Ans – ( D )

41. Which one of the following does not consist of transverse waves ?

( A ) light emitted by a CFL

( B ) TV signals from a satellite

( C ) ripples on the surface of a pond

( D ) musical notes of an orchestra

Ans – ( D )

42. Our ears are sensitive to sound frequencies between

( A ) 20 Hz to 20 kHz

( B ) 2 Hz to 20 Hz

( C ) 20 kHz to 200 kHz

( D ) 2000 kHz to 20000 kHz

Ans – ( A )

43. The equipment (device) used for locating the position and distance of an object inside sea, using ultrasound is called–

( A ) Pukar

( B ) Upkar

( C ) Radar

( D ) Sonar

Ans – ( D )

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

( A ) 20 m

( B ) 0.2 m

( C ) 200 m

( D ) 2 m

Ans – ( C )

45. Human ear can hear–

( A ) audible sound

( B ) infra sound

( C ) ultra sound

( D ) all the above

Ans – ( A )

46. In SONAR, we use

( A ) ultrasonic waves

( B ) infrasonic waves

( C ) radio waves

( D ) audible sound waves

Ans – ( C )

47. Sound travels

( A ) slower in warm air than in cold air

( B ) faster in solids and liquids than in air

( C ) slower in water than air

( D ) none of these

Ans – ( B )

48. In which medium sound travels faster–

( A ) solid

( B ) liquid

( C ) gas

( D ) none of these

Ans – ( A )

49. On increasing the temperature, the speed of sound in air

( A ) Increases

( B ) Decreases

( C ) Does not change

( D ) First increases then becomes constant

Ans – ( A )

50. Sound is produced by _________objects.

( A ) fast moving

( B ) vibrating

( C ) stationary

( D ) rotating

Ans – ( B )

51. Pitch of high frequency sound is–

( A ) high

( B ) low

( C ) zero

( D ) infinite

Ans – ( A )

52. Loudness measures the sound energy reaching the ear per second and depends on the amplitude of the sound wave. What is the unit used to measure the loudness of sound?

( A ) hertz

( B ) decibel

( C ) meter/second

( D ) second

Ans – ( B )

53. 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

( A ) Sound will be louder but the pitch will not be different

( B ) Sound will be louder and the pitch will also be higher

( C ) Sound will be louder but the pitch will be lower

( D ) Both loudness and pitch will remain unaffected

Ans – ( C )

54. Which of the following waves are produced by bats?

( A ) Infrasonic waves

( B ) Ultrasonic waves

( C ) Audible waves

( D ) All of these

Ans – ( B )

55. In case of transverse waves the particles of a medium vibrate

( A ) In the direction of wave propagation

( B ) Opposite to the direction of wave propagation

( C ) At the right angles to the direction of wave propagation

( D ) None of the above

Ans – ( C )

56. Maximum tolerable sound is

( A ) 0 dB

( B ) 10 dB

( C ) 60 dB

( D ) 120 dB

Ans – ( D )

57. The upper frequency limit of the audible range of human hearing is about

( A ) 20 kHz

( B ) 2000 Hz

( C ) 2 kHz

( D ) 2,000,000 Hz

Ans – ( A )

58. Sound travels in air if

( A ) particles of medium travel from one place to another

( B ) there is no moisture in the atmosphere

( C ) disturbance moves

( D ) both particles as well as disturbance travel from one place to another

Ans – ( D )