Question

Light from a laser forms a 1.31-mm diameter spot on a wall. If the light intensity in the spot is what is the power output of the laser?

Answer 1

0.04973 W

Step-by-step explanation:

I = Intensity of laser =
`3.69* 10^4\ W/m^2` (assumed, as it is not given)

d = Diameter of spot = 1.31 mm

r = Radius =
`(d)/(2)=(1.31)/(2)\ mm`

A = Area =
`\pi r^2`

Power is given by

`P=IA\\\Rightarrow P=3.69* 10^4* \pi ((1.31* 10^(-3))^2)/(4)\\\Rightarrow P=0.04973\ W`

The power output of the laser is 0.04973 W