NEET2009PhysicsElectromagnetic WavesActual
The electric field part of an electromagnetic wave in a medium is represented by : aligned & E _ x =0 & E _ y =2.5 N C [ (2 10^6 rad m ) t - ( 10⁻² rad s ) x ] aligned E_z=0 . The wave is :
Options
- AMoving along - x direction with frequency 10^6 ~Hz and wavelength 200 ~m
- BMoving along y direction with frequency 2 10^6 ~Hz and wavelength 200 ~m
- CMoving along x direction with frequency 10^6 Hz and wavelength 100 ~m
- DMoving along x direction with frequency 10^6 Hz and wavelength 200 ~m
Correct answer
D. Moving along x direction with frequency 10^6 Hz and wavelength 200 ~m
Step-by-step solution
As the coefficient of x is negative, it is moving along +ve x -axis and equating the equation aligned E _ y & =2.5 [ (2 10^6 ) t - ( 10⁻² ) x ] with y & = A ( t - kx ) & =2 106 f & = 2 =10^6 ~Hz k & = 10⁻² & = 2 k & = 2 10⁻² =200 ~m aligned