The electric field part of an electromagnetic wave in a

The electric field part of an electromagnetic wave in a medium is represented by E_x=0;
= E_y = 2.5 N cos 2π × 10⁶ rad - 1 π × 10^-2 rad x ;
C m s

E_{z_{= 0. The wave is :}}

1. moving along x direction with frequency 10⁶ Hz and wave length 100 m.
2. moving along x direction with frequency 10⁶ Hz and wave length 200 m.
3. moving along – x direction with frequency 10⁶ Hz and wave length 200 m.
4. moving along y direction with frequency 2π × 10⁶ Hz and wave length 200 m.

Comparing with the equation of wave.
E_y = E₀ cos (ωt – kx)
ω = 2 πf = 2π × 10⁶
∴ f = 10⁶ Hz
2π/λ = K
= π × 10^-2 m^-1, λ = 200 m