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Consider two metal spheres of radii

  • #1

Homework Statement


Consider two metal spheres of radii r1 = R and r2 = 2R, both charged to the same potential V0.
a) What is the ratio n1/n2 of their surface charge densities?


Homework Equations


n(eta) = charge/area
Er = -dV/dr


The Attempt at a Solution


a) n1/n2 = Q/(4*pi*R2) / Q/(16*pi*R2) = 4

The answer is supposed to be 2, and I don't know what I'm doing wrong.
 
Last edited:

Answers and Replies

  • #2
gneill
Mentor
20,793
2,773
The spheres are charged to the same potential (volts), not the same charge (Coulombs).
 

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