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Last Updated On 23-10-2022 - By Sara

A 27 mW laser beam has a cross-sectional area of 10 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by [Given permittivity of space ∈0 = 9 × 10−12 SI units, Speed of light c = 3 × 108 m/s]

a.

1 kV/m

b.

2 kV/m

c.

1.4 kV/m

d.

0.7 kV/m


Question ID - 50361 :-

A 27 mW laser beam has a cross-sectional area of 10 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by [Given permittivity of space ∈0 = 9 × 10−12 SI units, Speed of light c = 3 × 108 m/s]

a.

1 kV/m

b.

2 kV/m

c.

1.4 kV/m

d.

0.7 kV/m

1 Answer
5876 Votes
3537

Answer Key : (c) -

Intensity of EM wave is given by

I =  =  C

=  =  × 9 × 10−12 × E2 × 3 ×108

 E =  × 103 kV/m

     = 1.4  kV/m



Next Question :

Which one of the following can extinguish fire more quickly?

(a)

Cold water

(b)

Boiling water

(c)

Hot water

(d)

Ice


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