Important Questions for Class 8 Science Chapter 13 sound- Download Free PDF
CBSE Class 8 Science Chapter 13 Extra Questions
1. What are the differences between ultrasonic sound and infrasonic sound?
2. What is frequency?
3. What do you mean by audible sound?
4. What is 1 hertz equal to ?
(a) 1o vibrations per minute
(b) 1 vibration per minute
(c) 60o vibrations per minute
(d) 60 vibrations per minute
5. If a pendulum oscillates 20 times in 4 seconds. What is its time period?
(a) 0.001 sec.
(b) 0.05 sec.
(c) 0.2 sec.
(d) 0.1 sec
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