Fill in the blanks with suitable words.

(a) Time taken by an object to complete one oscillation is called ……………

(b) Loudness is determined by the …………… of vibration.

(c) The unit of frequency is ……………

(d) Unwanted sound is called ……………

(e) Shrillness of a sound is determined by the …………… of vibration.

A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

In the following statements, tick 'T' against those which are true and 'F' against those which are false.

(a) Sound cannot travel in a vacuum. (T/F)

(b) The number of oscillations per second of a vibrating object is called its time period. (T/F)

(c) If the amplitude of the vibration is large, the sound is feeble. (T/F)

(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T/F)

(e) The lower the frequency of vibration, the higher is the pitch. (T/F)

(f) Unwanted or unpleasant sound is termed as music. (T/F)

(g) Noise pollution may cause partial hearing impairment. (T/F)

Sound can travel through

1. gases only
2. solids only
3. liquids only
4. solids, liquids and gases