A 27mW laser beam has a cross-sectional area of 10mm2. The magnitude of the maximum electric field in this EM wave is given by [Given permittivity of space ε0=9×10−12F/m, speed of light c=3×108m/s]
A
2kV/m
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B
1kV/m
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C
0.7kV/m
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D
1.4kV/m
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Solution
The correct option is D1.4kV/m Given: P=27mW,A=10mm2
ε0=9×10−12F/m,c=3×108m/s
The intensity of the electromagnetic wave is given by,