The electric field part of an electromagnetic wave in a medium is represented by
`E_(x)=0,`
`E_(y)=2.5(N)/(C) cos[(2pixx10^(6)(rad)/(m))t-(pixx10^(-2)(rad)/(s))x]`
`E_(z)=0`.
The wave is

Options

A. moving along the x-direction with frequency ` 10^6Hz` and wavelength 100m
B. moving along the x-direction with frequency `10^6Hz` and wavelength 200m
C. moving along the x-direction with frequency `10^6Hz` and wavelength 200m
D. moving along the y-direction with frequency `2pixx10^6Hz` and wavelength 200m

Answer

b

Explanation

Given, `E_x=0, E_y=2.5N/C`
`xcos [(2pixx10^6(rad)/(m))t-(pixx10^-2(rad)/(s))x]`,
`E_z`=0. this shows that the wave is propagating
along positive x-axis.
Comparing the given equation with
`E_y=E_0cos (omegat-kx)`
we have, `omega=2pixx10^6`
or `2piv=2pixx10^6`
or `v=10^6Hz`
and `(2pi)/lambda=k=pixx10^-2`
or `lambda=(2pi)/(pixx10^-2)=200m`