Recent content by girlinphysics

When finding solutions to Maxwells equations we always cosider the case of a plane wave. But are plane waves real/physical solutions we can consider in real life? My guess is not because it is required to propagate infinitely. So why do we use plane waves to solve Maxwell's equations?

Where does the refractive index come from?

I came across this expression for the wave equation: \nabla^2E + \mu\sigma\frac{\partial{E}}{\partial{t}} - \frac{n^2}{c^2}\frac{\partial{E}}{\partial{t^2}} = 0 My question is what kind of medium is it for/where did it come from?

Khan Academy is a good place to start for really beginner level physics.

Is it possible to have a laser without a resonator? My guess is you can as you would still get some proportion of light coming from the inverted medium. My question is how would this light be different (from that of a laser with a resonator) and are there any practical uses for such a device?

This explains a lot, thank you very much for your answer!

In class we derived the relationship between temperature and heat capacity for the Debye model. We found that in 3D the heat capacity is proportional to temperature cubed. My question is, would this relationship change in a metallic system?

Oh okay, thank you very much for your help!

Homework Statement A thin lens is placed 2m after the beam waist. The lens has f = 200mm. Find the appropriate system matrix. This is a past exam question I want to check I got right. Homework Equations For some straight section [[1 , d],[0 , 1]] and for a thin lens [[1 , 0],[-1/f , 1]]...

In my course we are currently studyinh Bravis lattices. We were told that the reciprocal of the reciprocal lattice is the original lattice. This is very easy to prove when given an example of a SC/BCC/FCC lattice, however, is there a formal proof for this?

Oh yes it was! I've edited it now, thanks.

So I know that the basis vectors of an FCC in a symmetric form are: a = \frac{a}{2}(\hat{x} + \hat{y}) b = \frac{a}{2}(\hat{y} + \hat{z}) c = \frac{a}{2}(\hat{x} + \hat{z}) And that the reciprocal lattice vectors are the basis vectors of the BCC cells. I'm having a hard time doing the...

I am in my final year at university as undergraduate BSc student majoring in physics, and I am wanting to train in IP. I know about all the requirements and exams etc, my question is, am I at a loss compared to engineering students?

Yes I do know that.

I am getting really confused with the millions of different versions/forms of Maxwell's equations. I know there is differential form and integral form, but sometimes there is a B for magnetic field...other times there is an H. Sometimes there is dependence on \rho or J (current density) and...