An infinite, nonconducting sheet has a surface charge density σ = +8.58 pC/m2. (a) How much work is done by the electric field due to the sheet if a particle of charge q0 = 9.61×10−19 C is moved from the sheet to a point P at distance d = 4.49 cm from the sheet? (b) If the electric potential V is defined to be zero on the sheet, what is V at P ? (a) Number Units (b) Number Units