Q. The average electric field of electromagnetic waves in certain region of free space is $9 \times 10^{- 4}NC^{- 1}$. Then the average magnetic field in the same region is of the order of
A) $27 \times 10^{- 4}T$
B) $3 \times 10^{- 12}T$
C) $\left( \frac{1}{3} \right) \times 10^{- 12}T$
D) $3 \times 10^{12}T$
Explanation
(b) $E = 9 \times 10^{- 4}NC^{- 1}$
For electromagnetic waves, $\frac{E}{B} = c$ speed of light in vacuum
$\Rightarrow \frac{9 \times 10^{- 4}}{B} = 3 \times 10^{8}ms^{- 1} \Rightarrow B = 3 \times 10^{- 12}T$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.