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In a travelling plane electromagnetic wave, the maximum magnetic field is $1.26 \times 10^{-4} \mathrm{~T}$. The intensity of the wave is (Assume, $\mu_0=1.26 \times 10^{-6} \mathrm{H} / \mathrm{m}$ )
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Verified Answer
The correct answer is:
$1.89 \times 10^6 \frac{\mathrm{W}}{\mathrm{m}^2}$
Given, maximum magnetic field,
$\begin{aligned}
& B_0=1.26 \times 10^{-4} \mathrm{~T} \\
& \mu_0=1.26 \times 10^{-6} \mathrm{H} / \mathrm{m}
\end{aligned}$
$\therefore$ Intensity of EMW (Electromagentic wave) is given by
$\begin{aligned}
I & =\frac{1}{2} \frac{B_0^2 c}{\mu_0}=\frac{1}{2} \times \frac{\left(1.26 \times 10^{-4}\right)^2 \times 3 \times 10^8}{1.26 \times 10^{-6}} \\
& =\frac{1}{2} \times \frac{1.26 \times 1.26 \times 10^{-8} \times 3 \times 10^8}{1.26 \times 10^{-6}} \\
& =0.63 \times 3 \times 10^6=1.89 \times 10^6 \mathrm{~W} / \mathrm{m}^2
\end{aligned}$
$\begin{aligned}
& B_0=1.26 \times 10^{-4} \mathrm{~T} \\
& \mu_0=1.26 \times 10^{-6} \mathrm{H} / \mathrm{m}
\end{aligned}$
$\therefore$ Intensity of EMW (Electromagentic wave) is given by
$\begin{aligned}
I & =\frac{1}{2} \frac{B_0^2 c}{\mu_0}=\frac{1}{2} \times \frac{\left(1.26 \times 10^{-4}\right)^2 \times 3 \times 10^8}{1.26 \times 10^{-6}} \\
& =\frac{1}{2} \times \frac{1.26 \times 1.26 \times 10^{-8} \times 3 \times 10^8}{1.26 \times 10^{-6}} \\
& =0.63 \times 3 \times 10^6=1.89 \times 10^6 \mathrm{~W} / \mathrm{m}^2
\end{aligned}$
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