I hope this is the right forum for a first year undergraduate problem! The problem I've been working on is here: http://i.imgur.com/IhTtL.png I think that I have the correct answers, but I'm not sure. I think that the energy densities of the E and B field components will be (0.5)(ε0)(E^2) and (B^2)/(2μ0), that the ratio between the two is just 1/(c^2) and that the characteristic impedance of free space will be (Eμ0)/B. Can anyone confirm or deny those results? Thank you.