A + 29 nc charge is at the origin. how much farther from the charge is the 2000 v equipotential surface than the 3000 v surface?

The general formula for calculating charge is given by:

V=kq/r where V=Equipotential, k = Coulomb's constant = 9*10^9 Nm^2C^-2 and q = Charge in coulombs, and r = distance from to the equipotentiality surface.

Charge = + 29 nc = 29*10^-9 C

At 1000 V, r = kq/V = (9*10^9*29*10^-9) / 1000 = 0.261 m

At 3000 V, r=kq/V = (9*10^9*29*10^-9) / 3000 = 0.087 m

1000 V surface is (2.61-0.87) m further than 3000 V surface from the charge.

That is, 0.261-0.087 = 0.174 m