The electric field portion of an electrom agnetic wave is given by (a ll variables in SI u n its) E = `10^(-4) sin(6xx10^(5) t-0.01 x)` The frequency ( f) and the speed (v) of electrom agnetic wave are

Options

A. `f=30 //pi khz` and `v =1.5 xx10^(7) m//s`
B. `f=30 //pi khz` and `v =6.0 xx10^(7) m//s`
C. `f=300 //pi khz` and `v =6.0 xx10^(7) m//s`
D. `f=900 //pi khz` and `v =8.0 xx10^(7) m//s`

Answer

C

Explanation

`omega=6xx10^(5)=2pi f`
`f=(6)/(2pi)xx10^(5)=(3)/(pi)xx10^(5) Hz`
=`(300)/(pi)kHz`
wave speed =`(omega)/(k)`
`=(6xx10^(5))/(0.01)=6xx10^(7) m//s`