Question

The electric field part of an electromagnetic wave in a medium is represented by
$Ex=0,Ey=0,$
$E_Z=2.5\left(\left(2\pi \times {10}^6\right)t-\left(\pi \times {10}^{-2}\right)x\right]$
The wave is

• A. moving along positive x direction with frequency ${10}^{6}Hz$ and wavelength 100 $m$
• B. moving along negative x direction with frequency ${10}^{6}Hz$ and wavelength 200 $m$
• C. moving along positive x direction with frequency ${10}^{6}Hz$ and wavelength 200 $m$
• D. moving along positive z direction with frequency ${10}^{6}Hz$ and wavelength 200 $m$

Answer 1

The correct option is C moving along positive x direction with frequency ${10}^{6}Hz$ and wavelength 200 $m$

The form of wave is $E_Z=E_0(\omega t-kx)$ which represents the direction of propagation of wave is positive x direction.
Here , $\omega =2\pi \times {10}^6\Rightarrow 2\pi \nu =2\pi \times {10}^6\Rightarrow \nu ={10}^{6}Hz$
Also, $k=\frac{2\pi }{\lambda }\Rightarrow \frac{2\pi }{\lambda }=\pi \times {10}^{-2}$
$\Rightarrow \lambda =\frac{2\pi }{\pi \times {10}^{-2}}=2\times {10}^2=200m.$