# Search results

1. ### Dispersion question

No problem, I was at least relieved that I got the simple stuff first. As for the frequency dependence, I guess I'll take it for granted for now. Thanks.
2. ### Dispersion question

I get the notion that it's better to refer to frequency when we are talking about specific EM wave in the spectrum since it doesn't change when it propagates through mediums. Thanks anyway, I think I got it, the expression is valid only for a specific frequency of a wave. Now, I guess my real...
3. ### Dispersion question

Looking back, I think the texts are actually referring to the wavelength in vacuum. The expression above seems to be valid at least if we are concerned with the wavelength of the light as it passes through the medium. I'm now half convinced that we cannot conclude anything about the dependence...
4. ### Dispersion question

From the elementary texts, dispersion is the phenomenon where the refractive index of a medium depends on the wavelength of electromagnetic radiation through it. From what I've read, it is the wavelength of the radiation in vacuum. Also, it is said that the refractive index increases with...
5. ### I have troubles relating the idea with the formulas

When you have a formula, do you work on it's derivation in as much detail as possible? You might want to do it, it would give you a lot of insight on when a certain formula is applicable and not. Also, solving lots of problem is usually helpful with familiarizing yourself with it.
6. ### Question about PE and KE?

I think the simplest case is to look at work due to gravity: When, let's say you throw in a rock upwards, we know conceptually that the work done is negative since the weight is directed downwards and the displacement is upwards, also, the gravitational potential energy is given by U = mgh (m =...