JEE MAIN - Physics (2024 - 29th January Evening Shift - No. 12)
A plane electromagnetic wave of frequency $$35 \mathrm{~MHz}$$ travels in free space along the $$X$$-direction. At a particular point (in space and time) $$\vec{E}=9.6 \hat{j} \mathrm{~V} / \mathrm{m}$$. The value of magnetic field at this point is :
$$9.6 \hat{j} T$$
$$3.2 \times 10^{-8} \hat{i} T$$
$$9.6 \times 10^{-8} \hat{k} T$$
$$3.2 \times 10^{-8} \hat{k} T$$
Explanation
$$\begin{aligned} \frac{E}{B} & =C \\ \frac{E}{B} & =3 \times 10^8 \\ B & =\frac{E}{3 \times 10^8}=\frac{9.6}{3 \times 10^8} \\ B & =3.2 \times 10^{-8} T \\ \hat{B} & =\hat{v} \times \hat{E} \\ & =\hat{i} \times \hat{j}=\hat{k} \end{aligned}$$
So,
$$\overrightarrow{\mathrm{B}}=3.2 \times 10^{-8} \hat{\mathrm{k}} \mathrm{T}$$
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