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A thin spherical shell made of plastic carries a uniformly distributed negative charge of -Q coulombs. Two large thin disks made of glass carry uniformly distributed positive and negative charges S coulombs and -S coulombs. The radius of the plastic spherical shell is R1, and the radius of the glass disks is R2. The distance from the center of the spherical shell to the positive disk is d.

I want to know how to find two things:

  • The potential difference V1-V2. Point 1 is at the center of the plastic sphere, and point 2 is just outside the sphere.

  • The potential difference V2-V3. Point 2 is just below the sphere, and point 3 is right beside the positive glass disk.

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The geometry is confuse. Imo a sketch is needed. I think that the solution is directly available from textbooks. There is no need to calculate the potencial at the center. Do I feel home work? –  Helder Velez Feb 25 '11 at 13:03

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