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The electric field in an electromagnetic wave is given as E  = 20 sin         c x t j  NC –1 where ω and c are angular frequency and velocity of electromagnetic wave respectively. The energy contained in a volume of 5 × 10 –4 m 3 will be (Given ε 0 = 8.85 × 10 –12 C 2 /Nm 2 )

1. 88.5 × 10 –13 J
2. 17.7 × 10 –13 J
3. 28.5 × 10 –13 J
4. 8.85 × 10 –13 J

Correct answer: 8.85 × 10 –13 J

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