Question

An electromagnetic wave is propagating along $x-axis$. At $x=1cm$ and $t=10s$, its electric vector $\left|E\right|=6V/m$, then the magnitude of its magnetic vector is

• A. $2\times {10}^{-8}T$
• B. $3\times {10}^{-7}T$
• C. $6\times {10}^{-8}T$
• D. $5\times {10}^{-7}T$

Answer 1

The correct option is A

$2\times {10}^{-8}T$

Step 1. Given data:

$\left|E\right|=6V/m$, Magnitude of electric vector

$c=3\times {10}^8\raisebox{1ex}{$m$}\!\left/ \!\raisebox{-1ex}{$s$}\right.$

$\left|B\right|=?$, Magnitude of magnetic vector

Step 2. Calculating magnitude of magnetic vector,

Electric and magnetic fields are related by,

$$\begin{gathered} \left|B\right|=\frac{\left|E\right|}{c} \\ \Rightarrow \left|B\right|=\frac{6}{3\times {10}^8} \\ \therefore \left|B\right|=2\times {10}^{-8}T \end{gathered}$$

Hence, correct option is (A).