- #1
Eric Wright
- 16
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Homework Statement
By considering the E and B fields of an incident monochromatic plane wave on a metal surface, as well as the current density of mobile electrons, J and the resulting EM force F felt by them, show that there is a force on the metal due to the magnetic force on the mobile electrons.
Homework Equations
[tex] \vec F = q( \vec E + \vec v \times \vec B ) [/tex]
[tex] \vec E = E_0 e^{ky-wt} \hat k [/tex]
[tex] \vec B = \frac{E_0}{c} e^{ky-wt} \hat i [/tex]
The Attempt at a Solution
Let the surface be the zy plane. Then at the surface we have
[tex] \vec E = E_0 e^{-wt} \hat k [/tex]
[tex] \vec B = \frac{E_0}{c} e^{-wt} \hat i [/tex]
Consider a mobile electron on the surface. The E field will cause the electron to move in the -z direction. Then since the electron is now moving, the B field will exert a force in the
[tex] - \hat k \times \hat i = \hat j [/tex]
direction. Applying this to all mobile electrons we get a net force in the y direction on the surface.
I just wanted to see if my logic here is correct.. Am I missing any important details?
Any reply would be great.. thanks!
Eric