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

Options

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

Answer

d

Explanation

Electromagnetic wave equation
`E=E_(0) cos (kz-alpha t)` …..(i)
Speed of electromagnatic wave `v=(omega)/(k)`
Given, equation, `vecE=hati 40 cos (kz-6xx10^(8) t)` …..(ii)
Comparing Eqs. (i) and (ii), we get, `omega=6xx10^(8)`
Here, wave factor `k=(omega)/(v)=(6xx10^(8))/(3xx10^(8))=2 m^(-1)`