Rankers Physics

Properties of EM Waves: Practice Problem & Solution

In an electromagnetic wave in free space the root mean square value of the electric field is $E_{rms} = 6 V/m$. The peak value of the magnetic field is: (2017-Delhi)
$2.83 \times 10^{-8} T$
$0.70 \times 10^{-8} T$
$4.23 \times 10^{-8} T$
$1.41 \times 10^{-8} T$

Short Solution (Best for NEET):

To solve this problem, we apply the core principles of Properties of EM Waves. Understanding the underlying formula is key to arriving at the correct answer below:

The peak value of the electric field is $E_0 = \sqrt{2} E_{rms} = 6\sqrt{2} V/m$.
The peak value of the magnetic field is $B_0 = \frac{E_0}{c} = \frac{6\sqrt{2}}{3 \times 10^8}$.
$B_0 = 2\sqrt{2} \times 10^{-8} \approx 2.828 \times 10^{-8} T \approx 2.83 \times 10^{-8} T$.

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