Consider two metal spheres of radii

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SUMMARY

The discussion centers on calculating the ratio of surface charge densities for two metal spheres with radii R and 2R, both charged to the same potential V0. The initial calculation presented by the user incorrectly assumes equal charge, leading to a ratio of 4. The correct approach recognizes that the spheres have the same potential, resulting in a surface charge density ratio of 2. This highlights the importance of understanding the relationship between charge, area, and potential in electrostatics.

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  • Basic calculus for differentiation (dV/dr)
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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:
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The spheres are charged to the same potential (volts), not the same charge (Coulombs).
 

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