Question

an electromagnetic wave has an electric field with peak value 120. What is the averge energy delievered to a surface

Answer 1

The average energy delivered to a surface is 19.116 W/m².

Step-by-step explanation:

Given;

maximum electric field, E₀ = 120 v/m

The average energy delivered by the wave to a surface is given by

`I_(avg) = (c\epsilon_ o E_o^2)/(2)`

where;

c is the speed of light, = 3 x 10⁸ m/s

ε₀ is the permittivity of free space = 8.85 x 10⁻¹² c²/Nm²

`I_(avg) = (c\epsilon_ o E_o^2)/(2) \\\\I_(avg) = ((3*10^8)(8.85*10^(-12))( 120)^2)/(2)\\\\ I_(avg) =19.116 \ W/m^2`

Therefore, the average energy delivered to a surface is 19.116 W/m².