Question

What is the intensity (in W/m2) of an electromagnetic wave with a peak electric field strength of 115 V/m?

Answer 1

Given:

The peak electric field strength is: E = 115 V/m

To find:

The intensity of an electromagnetic wave.

Step-by-step explanation:

The intensity of an electromagnetic wave in terms of electric field intensity is given as:

`I=(c\epsilon_0E^2)/(2)`

Here, I = Intensity of an electromagnetic wave

c = The speed of light in a vacuum

ε₀ = The permittivity of free space

Standard data:

c = 3 × 10⁸ m/s

ε₀ = 8.854 × 10⁻¹² C²/N.m²

Substituting the values in the above equation, we get:

`\begin{gathered} I=\frac{3*10^8\text{ m/s}*8.854*10^(-12)\text{ C}^2\text{/N.m}^2*115\text{ V/m}}{\text{ }2} \\ \\ I=17.56\text{ W/m}^2 \end{gathered}`

Final answer:

The intensity of an electromagnetic wave is 17.56 W/m².