Electric potential at the surface?

Question

Hi,

Two spherical drops of mercury each have a charge of 0.9 nC and a potential of 390 V at the surface. The two drops merge to form a single drop. What is the potential at the surface of the new drop?

How would I begin this?


Thanks!

Answer 1

The volume a of a sphere varies like r^3 so the new sphere has radius of 2^(1/3) x radius of original. the charge on the new sphere has 2x the charge.
V1=constant q/r V2=constant 2q/2^(1/3)r
so V2=2^(2/3)V1