Question

If the frequency of sound waves produced by a siren increases from 400 Hz to 1200 Hz while the amplitude remains constant, then the ratio of intensity of 1200 Hz to the 400 Hz wave will be ______.

Options

• 1 : 3

• 3 : 1

• 9 : 1

• 1 : 9

Answer 1

If the frequency of sound waves produced by a siren increases from 400 Hz to 1200 Hz while the amplitude remains constant, then the ratio of intensity of 1200 Hz to the 400 Hz wave will be 9 : 1.

Explanation:

Intensity α (frequency)²

`("I"_1200)/("I"_400) = (1200/400)^2` = 9