Electric field in one electromagnetic wave, propagating in vacuum is `E=40 cos(kz - 6xx10^(8)t)hat(i)` (where all the values are in SI units). Then value of wave vector of this wave is ……. .

Options

A. `2m^(-1)`
B. `0.5 m^(-1)`
C. `6 m^(-1)`
D. `3m^(-1)`

Answer

A

Explanation

Comparing given equation with
`vec(E ) =E_(0)cos (kz - omega t)hat(i)`
we get `omega = 6xx10^(8)` rad/s
Now, we know `c=(omega)/(k)rArr k=(omega)/(c ) =(6xx10^(8))/(3xx10^(8))`
`therefore k = 2` rad/m