Consider two metal spheres of radii...

Sunshine748

1. The problem statement, all variables and given/known data
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?


2. Relevant equations
n(eta) = charge/area
E_r = -dV/dr


3. 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.

gneill

The spheres are charged to the same potential (volts), not the same charge (Coulombs).