Class 8 Science Chapter-12 Sound DAV|CBSE Book 2021
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Class 8 Science Chapter-12 : Sound
This Post Contains All The Exercises of Chapter 12 Science Of Class 8.
- A.Fill In The Blanks
- B. State True or False for the following statements
- C.Tick(√) The Correct Option
- D.Answer The Following Questions in Brief
- E.Answer The Following Questions
- Value Based Question
- Something To Do
SOMETHING TO KNOW
A. Fill in the blanks :
1. Birds have a ring of cartilage, called Syrinx in their wind pipes.
2. The SI unit of loudness' sound, is Decibel.
3. The pitch of sound is determined by its Frequency.
4. Sounds, of frequency more than 20 kHz, are known as Ultrasound.
5. An irregular, irritating sound is referred to as a Noise.
B. State True or False for the following statements :
1. Human beings, as well as all animals, have a voice box for producing their characteristic sounds.
Ans) False
2. Of the three mediums, solids, liquids and gases, sound propagates fastest in liquids
Ans) False
3. Sound cannot propagate through vacuum.
Ans) True
4. Light propagates, through vacuum, with a speed that is nearly a million times more than the speed of sound in air.
Ans) True
5. The frequency of a given sound determines its 'shrillness' or 'flatness'. Ans) True
6. Irregular non-periodic vibrations generally produce musical sounds.
Ans) False
C. Tick (✓) the correct option :
1. The maximum displacement of a vibrating body, on either side of its mean position, is known as its
Ans) Amplitude
2. The frequency of a given sound is 1.5 kHz. The vibrating body is then -
Ans) Completing 1,500 vibrations in one second.
3. Sound can propagate through -
Ans) All three states of matter.
4. When lightning and thunder take place, they occur -
Ans) Together but thunder is observed a little after the lightning.
5. A given sound is inaudible to the human ear. We can then say that this is so -
Ans) Only because its frequency is below 20 Hz.
6. The following are some statements about sound:
(i) Sound propagates faster in steel than in air.
(ii) Sounds are produced through vibrations.
(iii) Sound propagates faster than light.
(iv) Sound does not require a medium tor its propagation.
Out of these, the correct statements are -
Ans) (i) and (ii) only
SOMETHING TO KNOW
A. Fill in the blanks :
1. Birds have a ring of cartilage, called Syrinx in their wind pipes.
2. The SI unit of loudness' sound, is Decibel.
3. The pitch of sound is determined by its Frequency.
4. Sounds, of frequency more than 20 kHz, are known as Ultrasound.
5. An irregular, irritating sound is referred to as a Noise.
B. State True or False for the following statements :
1. Human beings, as well as all animals, have a voice box for producing their characteristic sounds.
C. Tick (✓) the correct option :
1. The maximum displacement of a vibrating body, on either side of its mean position, is known as its
Ans) Amplitude
2. The frequency of a given sound is 1.5 kHz. The vibrating body is then -
Ans) Completing 1,500 vibrations in one second.
3. Sound can propagate through -
Ans) All three states of matter.
4. When lightning and thunder take place, they occur -
Ans) Together but thunder is observed a little after the lightning.
5. A given sound is inaudible to the human ear. We can then say that this is so -
Ans) Only because its frequency is below 20 Hz.
6. The following are some statements about sound:
(i) Sound propagates faster in steel than in air.
(ii) Sounds are produced through vibrations.
(iii) Sound propagates faster than light.
(iv) Sound does not require a medium tor its propagation.
Out of these, the correct statements are -
Ans) (i) and (ii) only
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