Recent content by freesnow

Homework Statement The one-dimensional motion of a particle with coordinate q is governed by the Lagrangian L = (dq/dt)2(6q2 - 4qt(dq/dt) + (dq/dt)2t2) Show that the particle must be free Homework Equations The Attempt at a Solution I know that L needs to depend only on...

no, this is not homework, my lecture notes said the lowest order needs to be TM11 and TE10(or TE01), but I don't really understand it.

Why is the lowest order TM and TE mode TM11 and TE10(or TE01)? What is the physical meaning of the different orders of the modes? Thanks.

What is Einstein temperature? I know how to calculate it but I don't understard what it means...

I finally solved it! Thanks very much!

so U(x,s) = x/(s3+s2) but then I don't know how to do the inverse LT to get u(x,t) such that it fits the PDE... thanks

Thanks!

Homework Statement Use the Laplace Transform to solve the PDE for u(x,t) with x>0 and t>0: x(du/dx) + du/dt = xt with IC: u(x,0) = 0 and BC: u(0,t) = 0 Homework Equations The Attempt at a Solution After taking LT of the PDE wrt t, the PDE becomes x(dU/dx) + sU = x/(s2)...

Thanks. I just realized that I was in the wrong direction from the start, I've just now finished the argument using the law of conservation of electromagnetic energy instead.

Homework Statement In a Fabry-perot interferometer, light is reflected back and forth between 2 highly reflecting parallel mirrors, with a nonconducting medium inside. The waves of magnetic and electric field are 90o out of phase, unlike the case of a wave in free space where they in phase...