Question

The instantaneous oscillating electric field of EM wave is $E_0\hat{j}$ and magnetic field is oscillating along -ve $\left(\hat{k}\right)$ direction having magnitude $B_0$, then velocity of EM wave is

• A. $E_0{B}_0\hat{i}$
• B. $-E_0{B}_0\hat{i}$
• C. $-\frac{E_0}{B_0}\hat{i}$
• D. $-\frac{E_0}{B_0}\hat{k}$

Answer 1

The correct option is C $-\frac{E_0}{B_0}\hat{i}$

Given,
direction of electric field= $E_0\hat{j}$
and oscillation of magnetic field= $-B_0\hat{k}$
Direction of proportion $=\hat{E}\times \hat{B}$
$=\hat{j}\times (-\hat{k})=-\hat{i}$
And, magnitude $\left(V\right)=\frac{E}{B}$
Hence, $-\frac{E_0}{B_0}\hat{i}$