The electric field in an electromagnetic wave is given by E = (50 NC$-$1) sin$\omega$ (t $-$ x/c)
The energy contained in a cylinder of volume V is 5.5 $\times$ 10$-$12 J. The value of V is _____________ cm3. (given $\in$0 = 8.8 $\times$ 10$-$12C2N$-$1m$-$2)
Answer (integer)
500
Solution
$E = 50\sin \left( {\omega t - {\omega \over c}.\,x} \right)$<br><br>Energy density = ${1 \over 2}{ \in _0}E_0^2$<br><br>Energy of volume $V = {1 \over 2}{ \in _0}E_0^2.\,V = 5.5 \times {10^{ - 12}}$<br><br>${1 \over 2}8.8 \times {10^{ - 12}} \times 2500V = 5.5 \times {10^{ - 12}}$<br><br>$V = {{5.5 \times 2} \over {2500 \times 8.8}} = .0005{m^3}$<br><br>= .0005 $\times$ 10<sup>6</sup> (c.m)<sup>3</sup><br><br>= 500 (c.m)<sup>3</sup>
About this question
Subject: Physics · Chapter: Electromagnetic Waves · Topic: Maxwell's Equations
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