# Search results

1. ### What makes a door move, the torque or the force or both?

May be a relevent read: Leo Rausér's answer to Why exactly is it scientifically impossible to lift someone up by the neck? How strong do you have to be to do so? - Quora
2. ### A Small & large argument expansion of plasma dispersion function

Thanks you for the reply. Seems like I am not the only one who has this doubt :smile: ...
3. ### A Physical significance of growth rate in plasma

This kind of graph appears at many places where one invoke kinetic theory to study plasma. E.g. kindly see research article at...
4. ### A Physical significance of growth rate in plasma

Let us say that we have a dispersion relation curve and associated instability curve as shown below for a magnetised plasma, which have been formulated through kinetic theory. The frequencies and growth rate have been normalized w.r.t. cyclotron frequency of proton. My question is: what does...
5. ### A Small & large argument expansion of plasma dispersion function

In plasma physics we have what is known as plasma dispersion function. There are two approximation under which this function can be expanded: when the argument is less than 1, we can use power series expansion and when the argument is greater than 1 we can have asymptotic expression. My...
6. ### I Integration of 1 variable in 2 different ways.

I made lot many mistakes.... thanks for pointing out... thank you...
7. ### I Integration of 1 variable in 2 different ways.

OMG :nb). Ya, that's correct. But, if P and V is a function of x, then ??? Infact i did that calculation keeping this in mind that P and V is a function of x.
8. ### I Integration of 1 variable in 2 different ways.

I have to do a integration which goes like this: (V-M)(dP/dx)+3P(dV/dx)=0, (where M,P and V are constants). If you integrate with dx, you will get: ∫[(V-M)dP]+∫[3PdV]=0. which ultimately results in the answer M=4V. Now, i can put the first equation in this form also...
9. ### Questions that i posted

Thanks sir...
10. ### Questions that i posted

hello... i was using physics forum 1 year ago and i used to post some questions and some answers also. Now i would like to have a look on those older stuffs. But, i searched, in vain, extensively in PF. Can anyone guide me through this??? Thanks in advance...
11. ### Integrating sine where argument goes to infinity.

i understand that sir. But, when you do the maths it comes into picture. And this is why i posted the question here. Thank you...
12. ### Integrating sine where argument goes to infinity.

Okay. i am trying to derive a dispersion relation in magnetized plasma with kinetic approach. By the by i am taking only two terms, just forget about the last term in the above equation. We will encounter a term##I= \int_0^\infty cos(\phi-\phi')e^{g_1(\phi')}\,d\phi'\\## where ##g_1(\phi')= i...
13. ### Integrating sine where argument goes to infinity.

After some integration, i am getting a form e^{i \alpha\phi+i\beta\phi\sin(\phi-\phi')-i\gamma\sin\phi} , where ##\alpha, \beta, \gamma## are constants. Now i want to apply the limit where ##\phi ## ranges from 0 to ##\infty ## (ya, in the argument of sine we will encounter ##\infty ## which is...
14. ### Difference between generating function and Rodrigue's formula?

i saw this link before posting this question. but i don't think that it contain answer to my question....
15. ### X-ray diffraction or reflection?

Okay.. Thank you.....
16. ### Difference between generating function and Rodrigue's formula?

What is the difference between generating function and Rodrigue's formula? Some says that from generating function you can generate required polynomial (say for example from generating function of Legendre polynomial you can get Legendre polynomial.), but in that case,as far as i know, Rodrigues...
17. ### X-ray diffraction or reflection?

You (actually Wikipedia :wink:) are telling is that reflection ".... producing a diffraction pattern of regularly spaced spots known as reflections". But reflection is a physical phenomenon, so how cold you term spots as reflection??
18. ### X-ray diffraction or reflection?

does anybody have any other answer????
19. ### X-ray diffraction or reflection?

In x-ray diffraction , even though its reflection is happening , we call this as x ray diffraction. why is it so?? i don't know whether it has been discussed previously here.
20. ### PF is getting a face lift!

All the best...
21. ### Extensive and intensive quantities

What are the difference between extensive and intensive quantities?
22. ### What does paradox mean?

"A paradox is an argument that starts with apparently acceptable assumptions and leads by apparently valid deductions to an apparent contradiction." by Quantum Paradoxes: Quantum Theory for the Perplexed by Yakir Aharonov, Daniel Rohrlich.
23. ### Space- Time Unification

Thanks Ibix .. that was a nice one....
24. ### Space- Time Unification

sorry for that... What are the old and new concepts about space and time?
25. ### Space- Time Unification

What does actually mean by the saying that Einstein united space and time?
26. ### Diagonalizable matrix

The second question in that link gives us 3 eigenvalues in which 2 of them are equal. But the diagonalized matrix has no change.????
27. ### Lowest possible temperature

sorry... What? what does that last sentence says?
28. ### System in lowest energy sate

Say for example this: why does a (electric/magnetic)dipole placed in external electric/magnetic field align itself parallel to the field. Why?
29. ### Lowest possible temperature

it was a small mistake 0C meant degree centigrade.. i heard that it stems out from Charles's law
30. ### System in lowest energy sate

imbalance of what?