Plane EM wave,Electric field|Electromagnetic Waves|JEE-Main

JEE MAINS 2024

31.01.24 S1

Question

In a plane EM wave, the electric field oscillates sinusoidally at a frequency of $5 \times 10^{10} \mathrm{~Hz}$ and an amplitude of $50 \mathrm{Vm}^{-1}$. The total average energy density of the electromagnetic field of the wave is: $\left[\right.$ Use $\left.\varepsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 / \mathrm{Nm}^2\right]$

Select the correct option:

$1.106 \times 10^{-8} \mathrm{Jm}^{-3}$

$4.425 \times 10^{-8} \mathrm{Jm}^{-3}$

$2.212 \times 10^{-8} \mathrm{Jm}^{-3}$

$2.212 \times 10^{-10} \mathrm{Jm}^{-3}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$\begin{array}{ll}\text { Sol. } & U_E=\frac{1}{2} \in_0 E^2 \\ & U_E=\frac{1}{2} \times 8.85 \times 10^{-12} \times(50)^2 \\ & =1.106 \times 10^{-8} \mathrm{~J} / \mathrm{m}^3\end{array}$

Question Tags

JEE Main

Physics

Medium

Start Preparing for JEE with Competishun

Report Issue