- #1
Wesley Strik
- 8
- 1
Homework Statement
In free space, the electric field of a plane EM wave is given by: E(z,t)= 50î cos[wt-kz]
where w= 6 x 10^15
and k=2x10^7
(A) calculate the amplitude of the magnetic field H
How much energy does this wave transmit in 30s when it passes through a window of dimensions 2mx3m if the EM wave is incident:
(b) normally on the window
(c) obliquely at an angle of 30 degrees with respect to the window normal
Homework Equations
Maxwell:
curl E= dB/dt
--------------- relation H and B---
H=B/mu0
mu0=4pi x 10 ^-7
----------------------------------------
The Attempt at a Solution
For (A) I relate the two fields via the Maxwell curl E= dB/dt which yields:
50k j cos(wt-kz) = w B
such that B= 50k/w cos (wt-kz)
the amplitude becomes 50k/w=(10^9)/(6x10^15)= 1/6 x 10^-6
now relate this to H=B/mu0 ---> (1/6 x 10^-6)/(4pi x 10^-7)= (10/6) / (4pi) =0.13 A/m
did I d (A) correclty, does the outcome make sense?
Also, I have no clue how to do (b) and (c)?