The electric field associted with an electromagnetic wave in vacuum is given by `vecE=hati 40 cos(kz=6xx10^(8)t)`, when `E`, `z` and `t` are in volt/m metre and second respectively
find the wave vector.

Options

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

Answer

A

Explanation

On comparing the given equation to
`vecE=a_(0)hati cos (omega t-kz)`
`omega=6xx10^(8z)`,
`k=(2pi)/(r)=(omega)/(c)" "k=(omega)/(c)=(6xx10^(8))/(3xx10^(8))=2ms^(-1)`