Question

The loudness of sound depends upon

• A. Its velocity
• B. Its amplitude
• C. Its pitch
• D. Its frequency

Answer 1

The correct option is B

Its amplitude

Explanation of correct option: Option B

1. The intensity or loudness of a sound depends upon the extent to which the sounding body vibrates, i.e., the amplitude of vibration.
2. Sound is louder as the amplitude of vibration is greater, and the intensity decreases as the distance from the source increases.
3. The loudness of sound is proportional to the square of the amplitude of the vibration producing the sound, $loudness\propto amplitud{e}^2$.
4. Therefore, the loudness of sound depends on the amplitude of vibration. So, this is the correct option.

Explanation of incorrect Options:

Option A

1. There is no direct or indirect relationship between the loudness of a sound and its velocity.
2. Therefore, the loudness of a sound does not depend on its velocity. So, this option is incorrect.

Option C

1. There is no relation between the pitch of a sound and the loudness of a sound
2. Therefore, the loudness of a sound does not depend upon its pitch. So, this option is incorrect.

Option D

1. Frequency is the number of vibrations of the sound per second.
2. It will affect the pitch of the sound, not the loudness.
3. Therefore, the loudness of a sound does not depend upon its frequency. So, this option is incorrect.

Hence, the correct option is option B.