# Sound Frequency and Period Calculation

## What is the frequency of the sound produced by a cicada?

a) 128.6Hz

## What is the period of the sound produced by a cicada?

b) 0.0078 second

## Answer:

a) Frequency = 128.6Hz

b) Period = 0.0078 second

Frequency (f) is defined as the number of oscillation/vibration completed by a wave in one second. Mathematically, it is the ratio of the velocity of wave (v) to the wavelength (λ) of the wave. The formula for frequency is f = v/λ.

Given:

Velocity (v) = 346 m/s

Wavelength (λ) = 2.69 m

Substitute the values into the formula:

f = 346/2.69 = 128.6Hz

Period (T) is the time taken for a wave to complete an oscillation/vibration. Period is the reciprocal of the frequency. The formula for Period is T = 1/f. Given that frequency is 128.6Hz:

T = 1/128.6 = 0.0078 second

Therefore, the frequency of the sound produced by a cicada is 128.6Hz and the period is 0.0078 second.