Recent content by Chemist

  1. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    Oh, it seems I forgot to add that VT is the total potential of the entire system ( large + small spheres ). Oh , I think I should have said " V of the small sphere ". V1 It's the potential of the small sphere while V2 is the potential of the large sphere ( on its surface ). Why? I...
  2. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    Well I'm very grateful to you , I spent hours thinking about that ring problem ... our professor didn't give us a direct answer , he doesn't even explain things clearly , and his english sucks! :eek: Anyway, I have a question about another problem. A conductor spherical shell has a radius...
  3. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    You're absolutely right , I re-drew the figure & figured it out. In my figure, the y component cancels due to symmetry while the the x component does not. dEx = K dQ Cos(θ/2) dθ / R2 dEx = K L Cos(θ/2) dθ / R If I integrate, I get Ex = 2 K L Sin(θ/2) / R , which is the same as your...
  4. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    Ok,the arc opposing the gap and subtending angle θ is s, its length is s = θ R where R = radius of the ring θ = s / R = 0.1 radians Let L = lambda = linear charge density Let dθ be an infinitesimal arc of charge dQ The ratio dQ / ds = Q / s = L ( Lambda ) dEy = K dQ Sinθ / R2 =...
  5. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    Oh you're right, I made a silly mistake. The Gaussian surface should be a 3D. Yes, that's the only case I can work out, and it seems sufficient for an amateur ... Anyway, It makes much more sense now. I'll try to solve the problem considering the opposite arc, and see if I'll end up with...
  6. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    Thanks a lot for your help, nrqed. Yes, up to now, we have always assumed that the charge is uniform, the course I'm taking is basic. That's ok, we did problems on an arc of a ring, don't waste your time finding the expression. I still find it a bit complicated when working with...
  7. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    We studied how to calculate the electric field at a point M (x,0) from the center of the ring on its axis. But we have never computed the electric field inside a ring. So if there was no gap, the electric field would be 0 at its center? Also, I think since there's a charge in its center...
  8. C

    Determining Electric Field in a Ring-Shaped Charge Distribution

    There's a problem in Electricity I can't seem to figure out: A charged ring of radius 40 cm has a gap of 4 cm. Determine the electric field, at the center of the ring, when it carries a charge of 2 coulombs. I think that the linear charge density doesn't change much because of the small...
  9. C

    Geometrical Optics: Construct Ray Paths for Lens-Mirror System

    Absolutely nothing! Most questions involved in this course I am taking are similar to this, & most of the times I'm not quite sure where to start. I think it's trial & error all the way ...
  10. C

    Geometrical Optics: Construct Ray Paths for Lens-Mirror System

    A convex lens of focal length f is placed in front of a convex mirror having the same principal axis as the lens. Construct the path of a ray of light which coincides with the corresponding ray emerging from the lens-mirror system, and the path of the ray whose corresponding emergent ray is its...
Back
Top