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Electromagnetic wave striking a small pocket mirror

  • #1

Homework Statement


a plane electromagnetic wave of intensity 6.00 W/m^2, moving in the x direction, strikes a small pocket mirror of area 40.0cm^2, held in the yz plane.
(a) what momentum does the wave transfer to the mirror each second?
(b) find the force that the wave exerted on the mirror?
(c) explain the relationship between a and b


Homework Equations


I know how to get (b) and (c) but the first one is giving me the most trouble. I need help find U in order to get momentum from p= U/c


The Attempt at a Solution



given S I tried to calculate E and B to find Ue and Ub. I used I= E^2/2(mu)c arranged to be E= Sqrt and i used a few others to try to find U but nothing has been working. its telling me that the answer is 1.60 x 10^-10. im getting answers close to the answer but not the answer.
 

Answers and Replies

  • #2
Doc Al
Mentor
44,882
1,129
How does energy flux (S) relate to momentum flux?
 
  • #3
I meant I
 
  • #4
Doc Al
Mentor
44,882
1,129
I meant I
Same thing. How does energy relate to momentum for an EM wave?
 

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