The electric field associated with an electromagnetic wave in vacuum is given by `vecE=40cos(kz-6xx10^(8)t)hati,`
where E, z and t are in volt per meter, meter and second respectively. The value of wave vector k is

Options

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

Answer

A

Explanation

`vecE= 40 cos(kz- 6 xx 10^(8)t)hati`
`omega= 6 xx 10^(8)`
`k= (omega)/(v)= (6 xx 10^(8))/(3 xx 10^(8))= 2//m`