A laser beam has diameter 1.30 mm . The beam exerts a force of 3.6×10−9 N on a totally reflecting surface. What is the amplitude of the electric field of the electromagnetic radiation in this beam?

Explanation:

For a totally reflecting surface, the radiation pressure is related to the intensity of radiation by

(1)

where

I is the intensity of radiation

c is the speed of light

The radiation pressure is given by

where in this case:

is the force exerted by the beam

A is the area on which the force is exerted

The beam has a diameter of d = 1.30 mm, so its area is

Now we can write eq(1) as

From which we find the intensity of radiation, I:

Now we can find the amplitude of the electric field using the equation

where

is the vacuum permittivity

E is the amplitude of the electric field

And solving for E,

the first, second, and fifth options

where is the circuit diagram ?