Which of the following voices is likely to have minimum frequency?

(a) Baby girl

(b) Baby boy

(c) A man

(d) A woman

Choose the correct answer.

Sound can travel through

(a) gases only

(b) solids only

(c) liquids only

(d) solids, liquids and gases.

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

(a) Sound cannot travel in 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 vibration is large, 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)

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.