- #1
RubberBandit
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Homework Statement
An EM wave with intensity=200 W/m^2 is normal to a black .2m x .3m card that absorbs 100% of the wave. (a) Find the force exerted on the card by the radiation. (b) Find the force exerted by the same wave if the card reflects 100% of the light.Homework Equations
Pr=I/c Pressure=F/A
The Attempt at a Solution
Part (a) I solved. (I/c)(0.2*0.3)=F=4*10^-8 N
Part (b) I know is double the force.
My question is conceptual. Why is the force doubled when the EM wave is reflected?
Thank you for any and all replies.