Recent content by annms

I am a third year physics major and am studying quantum mechanics using Griffiths' textbook. I can do most of the problems with one star or no stars with relatively little effort, but a lot of the problems with three stars I find very difficult and I cannot do them at all. For the average...

So in cases when the charge is uniformly distributed over its volume or its surface, the sphere can be treated as a point charge?

Not much more to add to the title. I was just wondering, under what conditions can a charged sphere be treated as a point charge?

Thank you! So really the equality means- the change in potential energy is the negative of whatever the work done by a field (electric or gravitational). Correct?

Thanks for the responses. But let's say I do positive work in bringing a book up from the floor. It certainly increased potential energy, right?

Why is the change in potential energy the NEGATIVE of the work done by a force? What is the negative sign doing there, and what physical meaning does it serve? Any input is appreciated, but a rather detailed explanation would be great, as I am having much difficulty understanding this.

I have problems understanding the use of negative signs in SHM. ie. mx''=-kx Why is there a negative sign for the constant k and what does the negative sign mean?

Edit: Sorry I posted this in the wrong forum...I intended to post this in the Quantum Physics forum. Mods would you please move this post to the forum you see most appropriate.I am a newbie in learning quantum mechanics, so please view my opinion lightly: After learning a bit of QM, I feel...

Thank you for the responses guys. Forgive me for asking such a stupid question, I am a newbie to quantum mechanics. I was just reading my textbook and it first listed the total energy operator, then a few pages later it listed the Hamiltonian operator. It just looked very different than the...

What is the difference between the Hamiltonian operator and the Total energy operator? If both is used when working with total energy, why are there two different operators?

If light is quantized, and is given out in packets, why are the EM wave spectrum and the black body spectrum continuous? I am very confused, can someone offer some explanation? Any input is greatly appreciated.

Thanks. I think I'm getting it a little better. This was what really confused me: Let's say a spaceship is traveling at a speed near c relative to earth. If one hour has elapsed according to an Earth observer's clock, how much will have elapsed in the spaceship's clock according to the...

I keep reading that an observer will find the clock moving relative to him to be slower than his own local clock. But isn't his own local clock measuring proper time, which should be a shorter time period than the moving clock? How can the slower (moving) clock measure a longer time period...

Thank you guys for your input. And thank you lisab for actually reading my post. physiker- I never said the US is better at research than the UK. Read lisab's post. Ryker- Why would I say UK universities don't emphasize research? It is not me who thinks the UK doesn't emphasize on...

Hello there. I am a high school student with a passion for physics. I want to study physics in university and have applied to several universities in the UK. However, I've been recently told that the UK do not emphasize a lot on research...and that it would be better off for me to go...