(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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?

2. Relevant 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]

3. 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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# Homework Help: Radiation pressure

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