## Intensity formula

Intensity is the amount of energy a wave carries per unit time over an area of one unit area, which is equal to the energy density multiplied by the velocity of the wave. Usually measured in watts / square meters. The intensity depends on the intensity and amplitude of the wave. Intensity is represented by I.

**The intensity formula is expressed as: **

**I = P/A**

Here,

I= intensity

P= power

A= area of cross-section

## Solved examples

**1. Do you want to calculate the strength of a wave with a power of 25KW and a cross-section of 35x106m ^{2}?**

P = 25 KW = 25×10^{3} W, A =35×10^{6}m^{2}

Intensity formula

I= P/A

I = 25×10^{3} /35×10^{6}

=7.14×10^{-2} W/m^{2}

**2. Do you calculate the power of waves with intensity and cross-section of 30 × 10 ^{-5}W / m^{2} and 50m^{2} respectively?**

Given

I= 30×10^{-5 }W/m^{2}

A= 50 m^{2}

I = P/A

P = I x A

P = 30×10^{-5 } x 50

P= 0.015 W