A list of mediums is given below.

(i) wood (ii) water (iii) air (iv) vacuum

In which of these mediums can sound travel?

• i & ii only

• i, ii & ii only

• iii & iv only

• ii, iii & iv only

The loudness of sound depends on:

• its amplitude.

• its frequency.

• its time period

• its speed.

3. Which of the following statements are correct?

(1) 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.

• i & ii only

• i, ii & iii only

• ii, iii & iv only

• i, ii & iv only

An object is vibrating at 50 hertz. What is its time period?

• 0.02 s

• 2 s

• 0.2 s

• 20.0s

In order to reduce the loudness of a sound we have to

• Decrease its frequency of vibration of the sound.

• Increase its frequency of vibration of the sound.

• Decrease its amplitude of vibration of the sound.

• Increase its amplitude of vibration of the sound.

Loudness of sound is measured in units of

• Hertz (Hz)

• Decibel (dB)

• Metre (m)

• Metre/second (m/s)

The loudness of sound is determined by the

• Amplitude of vibration

• Ratio of amplitude and frequency of vibration

• Frequency of vibration

• Product of amplitude and frequency of vibration

1 hertz is equal to

• 1 vibration per minute

• 10 vibrations per minute

• 60 vibrations per minute

• 600 vibrations per mninute

Pitch of sound is determined by its

• Frequency

• Amplitude

• Speed

• Loudness

Ultrasound has frequency of vibration

• Between 20 and 20,000 Hz

• Below 20 Hz

• Above 20,000 Hz

• Between 500 and l0,000 Hz