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The electric field in an electromagnetic wave is given by E = 56.5 sin ω (t – x/c) NC –1 . Find the intensity of the wave if it is propagating along x -axis in the free space. (Given ∈ 0 = 8.85 × 10 –12 C 2 N –1 m –2 )

1. 5.65 Wm –2
2. 4.24 Wm –2
3. 1.9 × 10 –7 Wm –2
4. 56.5 Wm –2

Correct answer: 4.24 Wm –2

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