NCERT Solutions for Class 8 Science Chapter 13

NCERT Solutions for Class 8 Science Chapter 13 Sound (अध्याय 13: ध्वनि) to Study online or download free in PDF form. NCERT Solutions of other subjects are also available.


NCERT Solutions for Class 8 Science Chapter 13

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Sound: Question answers




Class 8 Science Chapter 13 Exercises Answers

NCERT Solutions for Class 8 Science Chapter 13 Sound
NCERT Solutions for Class 8 Science Chapter 13 in PDF




8 Science chapter 13

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Important Questions with answers

1. A list of mediums is given below.
(i) wood (iii) air (ii) water (iv) vacuum
In which of these mediums can sound travel?
(a) i & ii only
(b) i, ii & iii only
(c) iii & iv only
(d) ii, iii & iv only
2. Pitch of sound is determined by its
(a) frequency
(b) amplitude
(c) speed
(d) loudness
3. The loudness of sound depends on:
(a) its amplitude.
(b) its frequency.
(c) its time period.
(d) its speed.
4. An object is vibrating at 50 hertz. What is its time period?
(a) 0.02 s
(b) 2 s
(c) 0.2 s
(d) 20.0 s
5. The loudness of sound is determined by the
(a) amplitude of vibration
(b) ratio of amplitude and frequency of vibration
(c) frequency of vibration
(d) product of amplitude and frequency of vibration




6. In order to reduce the loudness of a sound we have to
(a) decrease its frequency of vibration of the sound.
(b) increase its frequency of vibration of the sound.
(c) decrease its amplitude of vibration of the sound.
(d) increase its amplitude of vibration of the sound.
7. 1 hertz is equal to
(a) 1 vibration per minute
(b) 10 vibrations per minute
(c) 60 vibrations per minute
(d) 600 vibrations per minute
8. Ultrasound has frequency of vibration
(a) between 20 and 20,000 Hz
(b) below 20 Hz
(c) above 20,000 Hz
(d) between 500 and 10,000 Hz
9. Which of the following statements are correct?
(i) Sound is produced by vibrations.
(ii) Sound requires a medium for propagation.
(iii) Light and sound both require a medium for propagation.
(iv) Sound travels slower than light.
(a) i & ii only
(b) i, ii & iii only
(c) ii, iii & iv only
(d) i, ii & iv only
10. Loudness of sound is measured in units of
(a) decibel (dB)
(b) hertz (Hz)
(c) metre (m)
(d) metre/second (m/s)


Answers
  • 1 (b)
  • 2 (a)
  • 3 (a)
  • 4 (a)
  • 5 (a)
  • 6 (c)
  • 7 (c)
  • 8 (c)
  • 9 (d)
  • 10 (a)

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