Let V = 20x²yz − 10z² V in free space.

(a) Determine the equations of the equipotential surfaces on which V = 0 and 60 V.

(b) Assume these are conducting surfaces and find the surface charge density at that point on the V = 60 V surface where x = 2 and z = 1. It is known that 0 ≤ V ≤ 60 V is the field-containing region.

(c) Give the unit vector at this point that is normal to the conducting surface and directed toward the V = 0 surface.