Question

A nonconducting sphere has a radius R=9.5 cm and uniformly distributed charge q=5.5e-12 C. Take the electric potential at the sphere's center to be zero. What is V at radial distance r=5.8 cm?

Answer 1

At any given distance r from center, electric potential would be,

V = (1/4 $\small \prod \sum$ _o)xQ(3R²-r²)/2R³

= 9x10⁹x5.5x10^-12x(3x0.095² - 0.058²)/2x0.095³

   =4.95x10^-2x0.0239/0.001714

=0.07 v

so, electric potential at r=5.8cm is 0.07 Volts.