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Lindsayyyy
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Homework Statement
A laser is focussed on an area A=0.1cm². The radiation pressure is p=10 pascal. Whats the power of the laser when 50% of the light is absorbed?
Homework Equations
I'm not sure, I tried it via:
Poynting vector:
[tex] S= \epsilon_{0}*c*E^{2} [/tex]
and radiation pressure
[tex]p=\epsilon_{0}*E^{2}[/tex]
The Attempt at a Solution
Because 50% is absorbed I think the pressure has to be divided by two. I solved the equation of the Poynting vector, so I have E² and put that in the equation for the pressure and I just solved it then, the solution is: 6*10^9 W/m² which I think is pretty high, but to be honest I'm not good in evaluations.
Can anyone help me out? Where are my mistakes? I'm a bit wondered too, because I didn't use the area which was given at all (the exercise has two more tasks, but it doesn't look like I need that A somewhere later).
Thanks for the help
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