Q 12-08-123JEE MainJEE Main 2022 (25 Jun, Shift 1)Medium
The electric field in an electromagnetic wave is given by $E = 56.5\sin\omega\left(t - \dfrac xc\right)\ \text{N C}^{-1}$. Find the intensity of the wave if it is propagating along the $x$-axis in free space. (Given $\varepsilon_0 = 8.85\times10^{-12}\ \text{C}^2\text{N}^{-1}\text{m}^{-2}$)
Answer: (C) $4.24\ \text{W m}^{-2}$
$$I = \frac12 c\varepsilon_0E_0^2 = \frac12\times3\times10^8\times8.85\times10^{-12}\times(56.5)^2 \approx 4.24\ \text{W m}^{-2}$$
Solution by Sreeraj P, M.Sc Physics