Question

In an electromagnetic wave in free space, the root mean square value of the electric field is $E_{rms}=6V/m$. The peak value of the magnetic field is

• A. $4.23\times {10}^{-8}T$
• B. $1.41\times {10}^{-8}T$
• C. $2.83\times {10}^{-8}T$
• D. $0.70\times {10}^{-8}T$

Answer 1

The correct option is C $2.83\times {10}^{-8}T$

As given, $E_{rms}=6V/m$
$E_o=E_{rms}\times \sqrt{2}$
where, $E_0$ is the peak value of electric field
$E_0=6\sqrt{2}V/m$

As, $E_o=C{B}_o$
Where,$C$ is the speed of light
$\Rightarrow B_o=\frac{E_o}{C}=\frac{6\sqrt{2}}{3\times {10}^8}$
$=2.828\times {10}^{-8}T$