# Search results

1. ### Srednicki 34.15 - Notation Question

Homework Statement Is the index notation in Srednicki's 34.16 correct given what he does in 35.29. Essentially, in going from 34.15 to 34.16, when taking the hermitian conjugate, he does not remove the dots. In going from 35.27 to 35.29, he has done so (the dot on 'a' has moved over onto...
2. ### Conducting planes in magnetostatics

Well. To put it in another way. How would the boundary conditions change in case the sheets were made out of dielectrics. As far as I understand, there cannot be any difference. Thanks a lot for answering. I had given up on it.
3. ### Conducting planes in magnetostatics

Homework Statement Two infinitely long perfectly conducting planes at x = 0 and y = 0 form a boundary on the upper right quadrant (x > 0, y > 0). A magnetic dipole m = m_x + m_y [with their corresponding unit vectors] is located at at (x', y', z' = 0) in the upper right quadrant. Find the...
4. ### Dipole interaction potential for mixed species

Homework Statement Not a homework question. I need the solution to this to model another problem. We all know the potential for the electromagnetic dipole dipole interaction (e.g. see Jackson) I want to know if there is a solution to the problem in which there are several replicas of the two...
5. ### Simple pendulum phase space

Homework Statement Pathria 2.6 (2nd Edition): Phase space volume of a simple pendulum. The total energy can be expressed in the form of the time derivative of the angle + the Sin^2 of that angle. From this I want to calculate the phase space volume. Mathematica gives the solution in the...
6. ### Jackson 6.5c

Homework Statement I need some guidance concerning Jackson 6.5c. Specifically I cannot get the -1/3 factor that the statement says I should. Homework Equations Solutions to part a and b which are given in the problem statement. The Attempt at a Solution -I started from the volume...
7. ### Retarded potential

For a while you had me worried :) I can change the limits later of course but I wanted to know how to solve that wretched integral. But I do think that the problem allows me to consider a point in a single plane. In any event, it seems that I am on the right track and only need to solve...
8. ### Retarded potential

Pretty sure that you have to and for two reasons: [1] Wiki says that its for time varying currents and charges without ever mentioning finiteness [2] Just saw that Griffiths example 10.2 solves for an infinite line current as well. However, the time dependence over there is not sinusoidal
9. ### Retarded potential

Homework Statement The question concerns a square loop in the presence of an infinitely long sinusoidally varying line current. The complete problem is http://physics.indiana.edu/~berger/p506_fall2008/p507ps11.pdf" [Broken] Homework Equations The retarded potential. The Attempt at a...
10. ### Jackson 6.4 (Multipole Expansion)

Ahh..so: (induced surface charge) + (induced volume charge) = 0. Thanks a lot.
11. ### Jackson 6.4 (Multipole Expansion)

I was (implicitly) under the impression that the rho calculated would be valid for the surface as well. Could you kindly give me a physical reason for its not being valid at the surface. Regards
12. ### Jackson 6.4 (Multipole Expansion)

Homework Statement Jackson 6.4b Homework Equations Multipole expansion especially Eq 4.9 in Jackson which is for a Quadrupole The Attempt at a Solution I found the result in 6.4a. The rho over there tells us that there is a charge density inside the sphere. Since the charge density...
13. ### Ideal gas law and temperature

Homework Statement This is Pathria (2nd Ed) 1.6 and it seemed simple enough but the magnitude of the answer seems unbelievably large: A cylindrical vessel 1 m long and .1 m in diameter is filled with a monoatomic gas at P = 1 atm and T = 300 K. The gas is heated by an electrical discharge...
14. ### Jackson Eq. 5.33 (3rd Ed.)

Thanks a lot :)
15. ### Jackson Eq. 5.33 (3rd Ed.)

Homework Statement I cant seem to figure out how he writes down this equation. Specifically: a. Isn't Theta' = 90 degrees. Then why doesn't he write it out explicitly. b. Whats the use of adding the Sin(Theta') if he is going to use a delta function using the Cos c. What is the radius 'a'...
16. ### Pauli Matrices under rotation

Homework Statement Can anyone tell me why Pauli Matrices remain invariant under a rotation. Homework Equations Probably the rotation operator in the form of the exponential of a pauli matrix having an arbitrary unit vector as its input. It may also be written as: I*Cos(x/2) - i* (pauli...
17. ### Euler angles and symmetric top

Homework Statement Check out problem 5.7 part a I want to express the exterior gravitational potential in terms of the Euler angles so that I might eventually use (dV/dB)B=B0 = 0 - the condition for equilibrium. I am therefore expecting the Lagrangian to be cyclic in terms of the other two...
18. ### Derive delta potential bound states from finite square well

Now I need help :)
19. ### Derive delta potential bound states from finite square well

I tried that as well. For example I started with Griffiths 2.153: E_n + V_o = (n^2 \pi^2 (h/2\pi)^2)/(2 m (2a^2)) but not only that V_o is approaching infinity but also that a is approaching 0. My attempt to make it so that the product of 'a' and V_o become a constant have been fruitless.
20. ### Derive delta potential bound states from finite square well

Homework Statement I have to show that the delta function bound state energies can be derived from the finite square well potential. Homework Equations The wave functions in the three regions for the finite square well. (See wikipedia) The Attempt at a Solution 1. I start from the...
21. ### Conformal map to convert circle to a line

Hmmm...seems very simple now that you have put it that way - guess thats the whole thing. Thanks a lot. Would try it as soon as I get the time
22. ### Conformal map to convert circle to a line

I need a conformal mapping that would map an ellipse or a circle to a line. I need this for the http://physics.indiana.edu/~berger/p506_fall2008/p506ps6.pdf" [Broken]. As far as I can understand, z^2 + 1/z^2 makes the geometry similar to that of a plane on the horizontal axis with a circle...