Question

The poynting vector of an electromagnetic wave in vacuum is s= 120w/m^2)sin^2(8.0rad/m)z+(2.4×10^9rad/s)t)k.what is the wavelngth?

Answer 1

Given:

Poynting vector, s = ( 120 w / m^2 ) sin^2 ( 8.0 rad / m ) z + ( 2.4 * 10^9 rad / s  ) t ) k

To find:

The wavelength.

Solution:

The equation of the electromagnetic wave,

E = E₀ sin^2 ( k x - w t ) i

Comparing,

We get,

k = 8

Hence,

Wavelength = 2 * π / k

π - 3.14

Substituting,

We get,

2 * 3.14 / 8

Hence, Wavelength = 0.3925 m