Recent content by quasar_4

Homework Statement I'm working my way through Wald's GR book and doing this geodesic problem: Show that any curve whose tangent satisfies u^\alpha \nabla_\alpha u^\beta = k u^\beta , where k is a constant, can be reparameterized so that \tilde{u}^\alpha \nabla_\alpha \tilde{u}^\beta =...

It still doesn't run. I get: $ gcc -Wall -I/usr/local/include -o a.out -c GLS-mc-demo.c $ ./a.out -bash: ./a.out: Permission denied $ I tried putting -c before -o as well and got the same result.

Hi, I'm stumped trying to learn how to use the GNU scientific library. I installed X11, Xcode and gsl library using MacPorts on my computer which is running Mac OSX 10.6.8. I've used Xcode plenty in the past year for generic (simple) c programs and it's worked fine, so I think all the...

Ok, thanks.

Homework Statement So I'm trying to show for a specific, given EM plane wave in vacuum that kx - \omega t = k' x' - \omega' t' but I'm running into some difficulties. I'm hoping someone can show me where I'm going wrong. Here's the setup: In the lab frame K, a plane EM wave traveling in...

Hm, ok, let me take a step back. So if I understand physically, the surface charge density should induce an electric field. If the surface charge density were uniform, the field would be all in the z-direction by symmetry. I'm having a hard time picturing in my mind what's happening with the...

Homework Statement The z=0 plane has a surface charge density \sigma(x,y) = \sigma0 \cos{(ax+by)} . Find the potential everywhere in space. Homework Equations The Attempt at a Solution Ok, so I tried to just integrate directly: \Phi = \frac{1}{4 \pi \epsilon0} \int_{-\infty}^{\infty}...

Thank you!

Homework Statement This should be simple: We have a charge density in some region of space, r< R (R is some known constant), that goes like 1/r. Everywhere else, the charge density is zero. I need to find the electric field and potential everywhere. The total charge is Q, assumed to be...

Homework Statement We have a solenoid of radius a, length L, with ends at z = +/- L/2. The problem is to use Ampere's law to show that the longitudinal magnetic induction just outside the coil is approximately B_z (\rho=a^+, z) \approx \left(\frac{2 \mu_0 N I a^2}{L^2} \right) \left(1+...

Hi everyone. I'm in my first semester of Jackson right now, and most of it's fine, but I'm having a hard time understanding the use of Green's functions as Jackson describes them in chapters 1-4. Does anyone know of another good physics reference that might be more clear? I have plenty of...

Update: after using continuity of phi across the boundary I got a third equation, which I used to find r0' = a^2/r0. But using that in my original two sets of equations gives me a q' and a q'' that both depend on theta... can that even be correct? Does it make physical sense that the value of q'...

All right, I've rethought this. Now I think it might be best to use images. So here's what I've got: Inside the sphere: \Phi_{in} = \frac{1}{4 \pi \epsilon_0} \left(\frac{q}{[r^2 + r_0^2 - 2 r r_0 \cos{\theta}]^{1/2}}+\frac{q'}{[r^2 + {r'}_0^2 - 2 r {r'}_0 \cos{\theta}]^{1/2}} \right)...

I don't know what to make of it that it doesn't mention an applied electric field in the dielectric. Should I then omit the E0*r*cos(theta) from my solution outside the sphere?

Homework Statement I am trying to find the force acting on a charge placed a distance r0 from the center of a spherical cavity of radius a. The entire cavity is immersed in a dielectric material, epsilon2. Homework Equations The Attempt at a Solution Here's my quandary: I can find the...