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The electric field (in \mathrm{NC}^{-1} ) in an electromagnetic wave is given by E= \mathrm{50 \sin \omega(t-x / c).} The energy stored in a cylinder of cross-section \mathrm{10 \mathrm{~cm}^2.} and length \mathrm{100 \mathrm{~cm}}, along the x-axis will be

Option: 1

5.5 \times 60^{-12} \mathrm{~J}


Option: 2

1.1 \times 10^{-11} \mathrm{~J}


Option: 3

2.2 \times 10^{-11} \mathrm{~J}


Option: 4

1.65 \times 10^{-11} \mathrm{~J}


Answers (1)

best_answer

Energy contained in a cylinder
\mathrm{\begin{aligned} & U=\text { avearge energy density } \times \text { volume } \\ & =\frac{1}{2} \varepsilon_0 E_0^2 \times A l \\ & =\frac{1}{2} \times\left(8.85 \times 10^{-12}\right) \times(50)^2 \times\left(10 \times 10^{-4}\right) \times 1 \\ & =1.1 \times 10^{-11} \mathrm{~J} \end{aligned}}

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shivangi.shekhar

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