electromagnetic-waves Question 4
Question: Q. 5. The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is (a) $c: 1$. (b) $c^{2}: 1$. (c) $1: 1$. (d) $\sqrt{c}: 1$.
[NCERT Exemplar]
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Solution:
Ans. Correct option : (c)
Explanation: Average energy by electric field $E_{0}$ is $U_{a v}$
$$ \begin{gathered} =\frac{1}{2} \varepsilon_{0} \cdot \frac{1}{\mu_{0} \varepsilon_{0}}\left(B_{0}\right)^{2} \quad \because c^{2}=\frac{1}{\mu_{0} \varepsilon_{0}} \ \text { Ratio }=\frac{\left(U_{a v}\right) \text { electric field }}{\left(U_{a v}\right) \text { magnetic field }}=\frac{1}{1} \text {, i.e., } 1: 1 \end{gathered} $$
