Question

A 25.8-mW laser beam of diameter 1.96 mm is reflected at normal incidence by a perfectly reflecting mirror. Calculate the radiation pressure on the mirror. 5.3654e- 5 X Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation.

Answer 1

The radiation pressure on the mirror is
`5.7*10^(-5)\ N/m^2`.

Step-by-step explanation:

Given that,

Power = 25.8 mW

Diameter = 1.96 mm

We need to calculate the force

Using formula of power

`P=Fc`

Where, P = power

F = force

c = light of speed

Put the value into the formula

`25.8 *10^(-3)=F*3*10^(8)`

`F=(25.8 *10^(-3))/(3*10^(8))`

`F=8.6*10^(-11)`

We need to calculate the radiation pressure on the mirror

Using formula of radiation pressure

`P=(2F)/(A)`

Put the value into the formula

`P=(2*8.6*10^(-11))/(\pi*(0.98*10^(-3))^2)`

`P=5.7*10^(-5)\ N/m^2`

Hence, The radiation pressure on the mirror is
`5.7*10^(-5)\ N/m^2`.