A plane electromagnetic wave of frequency `50 MHz` travels in free space along the positive x-direction. At a particular point is space and time, `vec(E)=6.3hatjV//m.` The corresponding magnetic field`hatB`, at that point wiil be:

Options

A. `6.3xx10^(-8)hatkT`
B. `18.9xx10^(-8)hatkT`
C. `2.1xx10^(-8)hatkT`
D. `18.9xx10^(8)hatkT`

Answer

C

Explanation

Poynting vector `vecS=1/(mu_(0))(vecExxvecB)`, gives the direction of propagation of em wage
Since `vecS` is along positive x, `vecE` along positive y, so `vecB` is along +z direction. Using `C=E/BimpliesB=E/C=6.3/(3xx10^(8))=2.1xx10^(-8)T` and `vecB=(2.1xx10^(-8)T)hatik`