# Search results

1. ### I Interpreting "momentum" in WKB approximation

Yeah I understand the interpretation regarding velocities... What's bothering me is the one regarding wavelengths.
2. ### I Interpreting "momentum" in WKB approximation

According to WKB approximation, the wave function \psi (x) \propto \frac{1}{\sqrt{p(x)}} This implies that the probability of finding a particle in between x and x+dx is inversely proportional to the momentum of the particle in the given potential. According to the book, R. Shankar, this is...
3. ### GRE with 3 years of Bachelors degree?

Hi, I am currently in my 3rd and final year of B.Sc Physics. Soon I'll have to start applying for a Masters degree. Is it true that you need 4 years of bachelor degree to get admitted for Postgraduate via GRE exam? If so, is there any university outside India which will accept my 3 year course...
4. ### Clarification about stationary quantum states of a system

I see... thank you for replying so early... Yes I kind of knew that ## \frac{\partial \psi}{\partial t}=0 ## is wrong... but in that short period of time I didn't even try to think... please don't start criticizing me for that...
5. ### Clarification about stationary quantum states of a system

Okay, here goes... Our teacher set a question in the last test which asked us to show that if a system initially be in a stationary state, it will remain in a stationary state even if the system evolves according to the time dependent Schrodinger equation. What I did was show that the...
6. ### Gauss' Law in a dielectric material

Okay. That was helpful. Thank you everyone for helping me with this. I have a better understanding now.
7. ### Gauss' Law in a dielectric material

. I agree to that and have understood this part. . This is what I'm talking about. Of course we have polarization charges on the surface and its the normal component of P... So why do we not bring it in the divergence equations?
8. ### Gauss' Law in a dielectric material

This part is alright, what's bothering me is that we are nowhere bringing the surface charge density in this derivation. Why is that? Or is it hiding somewhere!
9. ### Gauss' Law in a dielectric material

This is what we have in text-books and in Wikipedia: ρ=ρb+ρf and from there we get ∇.D=ρf. But I am unable to understand why we are not considering the bound surface charge in deriving this equation. Can anyone explain this to me.
10. ### Is the Moment of Inertia strictly different

Yes, but is that value strictly different for two different bodies? Or can two mass distribution have the same moment of inertia?
11. ### Is the Moment of Inertia strictly different

I mean to say that the bodies are not 2 dimensional, they only have length.. Like a rope. Only the distribution is not continuous, it is made of a number of masses
12. ### Is the Moment of Inertia strictly different

I would like to know if there is any proof as to whether the moment of inertia for two bodies (the masses of each body are distributed on a line) about their respective center of masses, is strictly different. If not, can anyone provide me a link to where the work is computed.
13. ### Width of a wire grid polarizer

how does that reduce the scattering of light.?
14. ### Width of a wire grid polarizer

Why is it that the width of a wire grid polarizer has to be less than the wavelength of the wave which I want to polarize? What would happen if the width was a little bit more?
15. ### Kelvin's thunderstorm generator

Ok... Now I understand what's going on! The fact that nothing is perfectly neutral is being exploited here. That's pretty clever actually... :D
16. ### Kelvin's thunderstorm generator

Yes I did see this, and the very 1st line is creating my confusion... “Any small charge on either of the two buckets suffices to begin the charging process." So at the start of the experiment, was one of the buckets charged? But I didn't see this being mentioned anywhere in the setup of the...
17. ### Kelvin's thunderstorm generator

I came across this experiment where two flowing streams of water, each falling through a can/inductor and finally falling into a bucket (metallic) creates a huge electrical potential difference! Ok I know that the falling water droplets have to acquire electrical charges, but I just can't figure...
18. ### Where to do my MSc?

Hello everyone, I am a 1st year undergraduate student of physics, in Kolkata,India. I wanted to know what good places are there to do my master's degree from, both in India and abroad, and what scholarships I can get. Thank you.
19. ### Photons being affected by pseudo forces

Ok... thanks to both of you for making this a bit more understandable.
20. ### Photons being affected by pseudo forces

And why does gravitation require a curved space-time?
21. ### Photons being affected by pseudo forces

Okay, so why do we take space-time to be globally curved and not straight?
22. ### Photons being affected by pseudo forces

I was reading a book called "Hyperspace", by Michio Kaku, and there he gave a sort of introduction to general relativity. Well its not at all technical, just for reading and knowing... There he claimed that space is curved because light rays will take a bent path inside an accelerating...
23. ### Car with a balloon

Ok. I understand. And then the balloon would start to oscillate in an awkward manner, just like 256bits said.
24. ### Car with a balloon

Seems similar! the only difference is that there the ball would be down, here the He balloon is up! Also, here the air plays an important role, something which I didn't want to consider, but I guess I was being stupid about that.
25. ### Car with a balloon

As a matter of fact, it did come to my mind when I thought of this experiment. Although it seemed interesting, I wasn't sure of it and that's why I didn't mention it earlier. Yes that can be, but its really a complicated situation. I wouldn't want to think about this before the getting a...
26. ### Car with a balloon

possible! very much! not me, but friends! but are you suggesting that I should use an ordinary balloon instead of a He one?
27. ### Car with a balloon

Yes I am aware of that... This is the case I had in mind. I have to admit, I really didn't think that there could be so many different situations to this same problem, but now that you explained them, I have a much broader view of this. Thanks a lot 256bits! Unfortunately, neither do...
28. ### Car with a balloon

Is there something wrong with the perpendicular force? If that is correct, shouldn't the balloon always try to move in a circle? I am sorry, I am a little biased with this problem, but isn't a force perpendicular to the motion the only requirement of a circular motion? I am not saying that the...
29. ### Car with a balloon

What if the car doesn't go in a circular track, just makes a turn with some radius for some short time interval? Will the balloon still trace a circular path?
30. ### Car with a balloon

Hi everyone, I was just wondering about this... If I tie a balloon outside a car, using a moderately long string, and the car heads for a left turn on the road with constant speed, then while turning, what would be the path followed by the balloon? I was thinking that maybe the balloon...