Question

The magnetic field in the plane electromagnetic wave is given by
`B_(z)=2xx10^(-7) sin(0.5xx10^(3)x+1.5xx10^(11)t)` tesla.
The expression for electric field will be:
A. `E_(z)=30sqrt(2) sin(0.5xx10^(3)x+1.5xx10^(11)t) V//m`
B. `E_(z)=60 sin (0.5xx10^(3)x+1.5xx10^(11)t) V//m`
C. `E_(y)=30sqrt(2) sin (0.5xx10^(11)x+0.5xx10^(3)t) V//m`
D. `E_(y)=60 sin(0.5xx10^(3)x+1.5xx10^(11)t) V//m`

Answer 1

Correct Answer - d
Wave is propagating along positive `X`-axis, magnetic field is directed along `Z`-axis so electric field must be directed along `(hatkxxhati)=hati`, along `Y`-axis.
Amplitude of electric field
`E_(0)=B_(0)c=2xx10^(-7)xx3xx10^(8)=60 V//m`
So choice (d) is correct.