Frequency is a property of a wave. Frequency is the number of waves that pass a fixed point in unit time. Frequency is measured in units of hertz (Hz).

**Formula 1 to calculate frequency.**

To calculate frequency we find the reciprocal of period.

**Example:**

What is the frequency of a sound wave with a period of 0.04s .

The frequency of the wave is 25 Hz.

**Formula 2 to determine frequency.**

**Example:**

What is the frequency of a sound wavelength that travels with a speed of 340 m/s and its length is 0.15 m.

The frequency of the wave is 2,266.67 Hz.