Question

The amplitude of the sinusoidially oscillating electric field of a plane wave is $60\, V/m$ . Then the amplitude of magnetic field is:

• A. $2\times {{10}^{2}}T$
• B. $6\times {{10}^{7}}T$
• C. $6\times {{10}^{2}}T$
• D. $2\times {{10}^{-7}}T$

Answer 1

Answer: (D)

$2\times {{10}^{-7}}T$

Answer 2

The instantaneous magnitudes of electric field (E) and magnetic field (B) are related as
$\frac{E}{B}=c$ $\Rightarrow$ $B=\frac{E}{c}$
Given, $E=60\,V/m,c=3\times {{10}^{8}}m/s$
$\therefore$ $B=\frac{60}{3\times {{10}^{8}}}=2\times {{10}^{-7}}T$