Question

The oscillating magnetic field in a plane electromagnetic wave is given by $B_y=5 \times 10^{-6} \sin 1000 \pi\left(5 x-4 \times 10^8 t \right) T$. The amplitude of electric field will be :

• A. $15 \times 10^2 Vm ^{-1}$
• B. $5 \times 10^{-6} Vm ^{-1}$
• C. $16 \times 10^{12} Vm ^{-1}$
• D. $4 \times 10^2 Vm ^{-1}$

Answer 1

Answer: (D)

$ B _0=5 \times 10^{-6} $
$ v =$ Speed of wave $=\frac{4 \times 10^8}{5}=8 \times 10^7$
$ {\left[\therefore v =\frac{ w }{ k }\right]} $
$E _0= vB _0=40 \times 10^1 $
$ =4 \times 10^2 V / m $