- #1

rugerts

- 153

- 11

## Homework Statement

A light source radiates a sinusoidal electromagnetic wave uniformly in all directions. This wave exerts an average pressure p on a perfectly reflecting surface a distance R away from it. What average pressure (in terms of p) would this wave exert on a perfectly absorbing surface that was twice as far from the source?

## Homework Equations

pressure radiation of perfect absorber = (Intensity)/(speed of light)

pressure radiation of perfect reflector = (2 * Intensity)/(speed of light)

Intensity = (Power)/(Area)

Surface Area of Sphere = 4*pi*R^2

## The Attempt at a Solution

Since you probably can't see that, here's an imgur link: https://imgur.com/a/uxltWGV

When I try to do the math, I get that it's a factor of 1/8. But, if I try to reason through it, it seems like 1/4 is a reasonable answer since I'm just doubling a square factor.

Thanks for your time.