Question

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by in SI units. What is the frequency of the wave

Answer 1

Answer:

$f=1.98\times 10^5\ Hz$

Explanation:

The magnetic field of a plane-polarized electromagnetic wave moving in the z-direction is given by :

$B=1.2\times 10^{-6}\sin [2\pi (\dfrac{z}{240}-\dfrac{10^7t}{8})]$ .....(1)

The general equation of the magnetic field wave is given by :

$B=B_o\sin (kz-\omega t)$ ....(2)

Equation (1) is in form of equation (2), if we compare equation (1) and (2) we find that,

$\omega=\dfrac{10^7}{8}$

We need to find the frequency of the wave. It is given by :

$f=\dfrac{\omega}{2\pi}\\\\f=\dfrac{10^7}{8\times 2\pi}\\\\f=1.98\times 10^5\ Hz$

So, the frequency of the wave is $1.98\times 10^5\ Hz$