1. A nonconducting sphere has radius R=2.31cm and uniformly distributed charge q = +3.50fC. Take the electric potential at the sphere's center to be Vo = 0. What is V at radial distance (a) r =1.45cm and (b) r = R.
( answer is given as (a) is -0.268mV (b) -0.681mV, please show me the detail, thank you)
2. Two particles, of charges Q1 and Q2, are separated by distance d horizontally. The net electric field due to the particles is zero at x = d/4. With V = 0 at infinity, locate (in terms of d) any point on the x axis (other than at infinity) at which the electric potential due to the two particles is zero.