WBBSE For Class 9 Physical Science And Environment Chapter 7 Sound MCQS

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Chapter 7 Sound MCQs

Question 1. Sound can not travel through

  1. Air
  2. Water
  3. Steel
  4. Vacuum

Answer: (4) Vacuum

Question 2. Which frequencies are not audible to the human ear?

  1. 30 Hz
  2. 3000 Hz
  3. 300 Hz
  4. 30,000 Hz

Answer: (4) 30,000 Hz

Read And Learn More WBBSE Solutions For Class 9 Physical Science And Environment MCQS

Question 3. The frequency of sound waves can be expressed in

  1. Hz
  2. dB
  3. m
  4. m/s

Answer: (1) Hz

WBBSE For Class 9 Physical Science And Environment Chapter 7 Sound MCQS

WBBSE Class 9 sound chapter MCQs with answers

Question 4. Frequency (n) and period (T) are related as

  1. \(\frac{n}{T}\)=1
  2. n×T=1
  3. n=\(\mathrm{T}^2\)
  4. n\(\mathrm{T}^2\)=1

Answer: (2)

Question 5. The audible range of frequency in Hz is

  1. 20 to 20,000
  2. 2000 to 20,000
  3. 40 to 4000
  4. 200 to 2000

Answer: (1) 20 to 20,000

Question 6. Earthquake produces

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

Answer: (3) Infrasonic sound

Question 7. In SONAR, we use

  1. Radio waves
  2. Ultrasonic waves
  3. Infrasonic waves
  4. Audible sound waves

Answer: (2) Ultrasonic waves

Sound multiple choice questions for WBBSE Class 9

Question 8. Due to the increase in the frequency of the sounding source, its pitch

  1. Increases
  2. Decreases
  3. Remains the same
  4. First increases and then decreases

Answer: (1) Increases

Question 9. Stethoscope works on the principle of

  1. Reflection of sound
  2. Refraction sound
  3. Reverberation of sound
  4. None of these

Answer: (1) Reflection of sound

Question 10. The relation between velocity (v) of sound, wavelength (λ), and frequency (n) is

  1. n\(=\frac{v}{\lambda}\)
  2. λ=vm
  3. n= λv
  4. n\(=\frac{v^2}{\lambda}\)

Answer: (1) n\(=\frac{v}{\lambda}\)

Question 11. The velocity of sound in dry air at 0°C is

  1. 233 m/s
  2. 330 m/s
  3. 332 m/s
  4. 200 m/s

Answer: (3) 332 m/s

Important sound chapter questions for Class 9 Physical Science

Question 12. The minimum distance of the reflector creating an echo of a transient sound is

  1. 33m
  2. 16.6 m
  3. 33 cm
  4. 10m

Answer: (2) 16.6 m

Question 13. Propagation of sound requires

  1. No medium
  2. Material medium
  3. Only gaseous medium
  4. Aqueous medium

Answer: (2) Material medium

Question 14. Echo of sound is caused by

  1. Violent sound
  2. Flow of air
  3. Reflection of sound
  4. Refraction of sound

Answer: (3) Reflection of sound

Question 15. The unit of intensity of sound is

  1. Hertz
  2. m/\(s^2\)
  3. Decibel
  4. Dyne

Answer: (3) Decibel

WBBSE Class 9 Physical Science MCQs on sound waves

Question 16. Due to the propagation of a longitudinal wave through a medium, particles of the medium vibrate

  1. Along and perpendicular to the direction of the wave
  2. In all directions
  3. Along the direction of the wave
  4. Within a liquid

Answer: (3) Along the direction of the wave

Question 17. A transverse wave is produced in

  1. Gas only
  2. A liquid
  3. In gas, solid and liquid
  4. Solid only

Answer: (3) In gas, solid and liquid

Question 18. Distance traveled by a wave in one second is its

  1. Velocity
  2. Wavelength
  3. Period
  4. Frequency

Answer: (1) Velocity

Question 19. The correct formula is

  1. v\(=1 / T\)
  2. v=nλ
  3. \(=\frac{v}{\lambda}\)
  4. v=\(\mathrm{n}_2\).λ

Answer: (2) v=nλ

Solved MCQs on sound for WBBSE Class 9

Question 20. The loudness of the sound depends on

  1. Wavelength of sound
  2. Volume of air around the source of sound
  3. Time of day
  4. Reflection of sound

Answer: (1) Wavelength of sound

Question 21. The human ear is sensitive normally between the frequencies

  1. 20-20,000 Hz
  2. 10-100 Hz
  3. 1-10 Hz
  4. Above 20,000

Answer: (1) 20-20,000 Hz

Question 22. For hearing echo the minimum time difference between the direct and the reflected sound should be

  1. 1/5 sec
  2. 1/10 sec
  3. 1 sec
  4. 2 sec

Answer: (2) 1/10 sec.

Question 23. For a sound of wavelength 10 cm and frequency 10 created in a medium, the velocity of a sound wave is

  1. 10 cm/sec
  2. 100 cm/sec
  3. 5 cm/sec
  4. 20 cm/sec

Answer: (2) 100 cm/sec

Question 24. The surface of a wall can reflect sound waves and not light waves because

  1. Sound has bigger wavelength
  2. The wall is large
  3. Sound has less velocity
  4. Sound has bigger velocity

Answer: (1) Sound has bigger wavelength

Question 25. Elastic transverse waves can propagate through

  1. Gaseous medium not through solid medium
  2. Neither gaseous nor solid medium
  3. Solid and gaseous medium
  4. Solid medium, not through gaseous medium

Answer: (4) Solid medium, not through gaseous medium

Question 26. Repeated reflection of sound produces

  1. Stationary wave
  2. Echo
  3. Reverberation
  4. Refraction

Answer: (2) Echo

Question 27. The velocity of a sound wave of wavelength 1 in a medium is v, The wavelength of the wave in the medium of the velocity is 4 v, is

  1. λ/2
  2. 2/λ
  3. 4/λ
  4. 2/λ

Answer: (3) 4/λ

Question 28. The difference in intensity between two sound waves is 1 Bel. It means that the ratio of their intensities is

  1. 5:1
  2. 105
  3. 1:4
  4. 100: 4

Answer: (3) 1:1

Question 29. Which of the following is not true?

  1. Sound waves do not propagate in straight lines
  2. Sound wave carries energy
  3. Sound waves travel faster in a vacuum than in air
  4. Sound waves propagate in straight lines

Answer: (3) Sound waves travel faster in vacuum than in air

Reflection and refraction of sound MCQs Class 9 WBBSE

Question 30. The pitch of a note depends on the

  1. Frequency
  2. Velocity of sound
  3. Wavelength of sound
  4. Amplitude of wave

Answer: (3) Wavelength of sound

Question 31. The velocity of sound is greatest in

  1. Mercury
  2. Water
  3. Steel
  4. Air

Answer: (3) Steel

Question 32. The sound of thunder is heard after 5.5 sec after the flash. If the velocity of sound in air is 330 m/sec, the distance of the thunder is

  1. 18.15 km
  2. 1.815 km
  3. 0.1815 km
  4. 181.5 km

Answer: (2) 1.815 km

Question 33. A person fires a pistol standing between two hills. He hears echoes at 1-sec intervals. If the velocity of sound in air is 340 m/sec, the distance between the mountains is

  1. 340 m
  2. 170 m
  3. 510 m
  4. 66 m

Answer: (2) 170 m

Question 34. The characteristic by which two sounds of the same frequency and loudness can be differentiated is

  1. Velocity of sound
  2. Quality
  3. Pitch
  4. Medium in which the sound travels

Answer: (3) Pitch

Question 35. When a wave travels from one medium to another, the parameter of the wave
remaining unchanged is

  1. Quality
  2. Velocity
  3. Frequency
  4. Wavelength

Answer: (1) Quality

Question 36. What should be the minimum frequency of a vibrating body producing sound?

  1. 2000 Hz
  2. 100 Hz
  3. 20 Hz
  4. 150 Hz

Answer: (3) 20 Hz

Best multiple choice questions on sound for WBBSE Class 9

Question 37. How does the pitch of sound depend on frequency?

  1. Pitch increases with a decrease in frequency
  2. Pitch decreases with increase in frequency
  3. Pitch increases or decreases accordingly with an increase or decrease in frequent
  4. Pith remains constant

Answer: (3) Pitch increases or decreases accordingly with increase or decrease in frequency.

Question 38. The Unit Of Frequency is

  1. ohm
  2. mho
  3. Hz
  4. Torr

Answer: (3) Hz

Question 39. Migraine is caused by

  1. Sound pollution
  2. Air pollution
  3. Water pollution
  4. Land pollution

Answer: (1) Sound pollution

Question 40. When one end of a long iron pipe is struck, sounds are heard.

  1. Two
  2. Three
  3. Four
  4. One

Answer: (1) Two

Question 41. The relation between the velocity (v) of sound and its density (d) is 

  1. \(v \propto \frac{1}{d}\)
  2. \(v \propto \frac{1}{\sqrt{d}}\)
  3. \(\frac{1}{d}\)
  4. V α T

Answer: (2)\(v \propto \frac{1}{\sqrt{d}}\)

Question 42. The relation between the velocity (v) of sound with the absolute temperature (T) is

  1. v α \(\sqrt{T}\)
  2. v α T
  3. v=T
  4. v= \(\sqrt{T}\)

Answer: (1) v α \(\sqrt{T}\)

Question 43. If the size of the sounding body is bigger then the intensity of the sound will be

  1. Increased
  2. Decreased
  3. Same
  4. Constant

Answer: (1) Increased

Question 44. The velocity of sound through iron is then the velocity of sound through air.

  1. 4 times
  2. 10 times
  3. 15 times
  4. 5 times

Answer: (3) 15 times

WBBSE Class 9 Physical Science speed of sound MCQs

Question 45. The sensation due to sound lasts for about

  1. \(\frac{1}{20}\) second
  2. \(\frac{1}{10}\) t second
  3. \(\frac{1}{30}\) Secon
  4. \(\frac{1}{5}\) secon

Answer: (2) \(\frac{1}{10}\) second

Question 46. If the wave length is and the velocity of sound 1.7 m is 340 m/sec then what will be the wave frequency?

  1. 20 Hz
  2. 200 Hz
  3. 2000 Hz
  4. 2 Hz

Answer: (2) 200 Hz

Question 47. What is the fundamental tone if the tones in a note are of 100, 150, 200, 280, 300, 450, and 500?

  1. 100
  2. 280
  3. 500
  4. 450

Answer: (1) 100

Question 48. The sound of lightning is heard 6 sec after it is seen. If the velocity of sound is 330 m/sec at that time, what will be the distance of the cloud?

  1. 1980 m
  2. 2000
  3. 330 m
  4. 350 m

Answer: (1) 1980 m

Question 49. Wave motion transfers

  1. Matter
  2. Energy
  3. Momentum
  4. All of these

Answer: (2) Energy

Question 50. The distance between two successive compressions is

  1. λ/2
  2. λ/4
  3. λ
  4. 2 λ
  5. Answer: (3) λ

Question 51. Sound waves can travel

  1. Only in solid
  2. Only in liquid
  3. Only in gas
  4. In all (Solid, Liquid, gas)

Answer: (4) In all (Solid, Liquid, gas)

Question 52. The speed of sound in air

  1. Decreases with increase in temperature
  2. Remains the same with an increase in temperature
  3. Remains the same with a decrease in temperature
  4. Increases with increase in temperature

Answer: (1) Decreases with an increase in temperature

Question 53. Sound wave is

  1. Transverse
  2. Longitudinal
  3. Both transverse and longitudinal
  4. None of these

Answer: (2) Longitudinal in nature

Question 54. The distance between a compression and the adjoining rarefaction is

  1. λ/4
  2. λ/2
  3. (3) λ
  4. 2λ

Answer: (2) λ/2

Question 55. Which of the following waves is a mechanical wave?

  1. Lightwave
  2. Sound wave
  3. X-rays
  4. Ultra-violet ray

Answer: (2) Sound wave

Question 56. The speed of sound is maximum in

  1. Air
  2. Hydrogen
  3. Water
  4. Iron

Answer: (4) Iron

Question 57. In SONAR, we use

  1. Infrasonic
  2. Radiowaves
  3. Audible sound
  4. Ultrasonic

Answer: (4) Ultrasonic

Question 58. Infrasound can be heard by

  1. Bat
  2. Rhinoceros
  3. Dolphins
  4. Human beings

Answer:(2) Rhinoceros

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