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A 27 mW laser beam has a cross-section...

A 27 mW laser beam has a cross-sectional maximum electric field in this electromagnetic wave is given by :
[Given permittivity of space `in_(0) = 9 xx 10^(12)` SI units, Speed of light `c= 3 xx 10^(8) m//s`]

A

`1 k V // m`

B

1.4 kV/m

C

0.7 kV/m

D

2k V/m

Text Solution

Verified by Experts

The correct Answer is:
B
`I = (P)/(A) = (1)/(2) epsilon_(0) E_(0)^(2) C `
`:. E_(0) = sqrt((2P)/( epsilon _(0) CA)) = sqrt(( 2 xx 27 xx 10^(-3) xx 36 pi xx 10 ^(9))/(3 xx 10 ^(8) xx 10 xx 10 ^(-6)))`
`= 1.4 kV//m`
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