Question

(a) If the electric field is zero in some region of space, the electric potential must also be zero in that region 1. true 2. false Enter (143 points] 0 attempt(s) made (maximum allowed for credit- 1) (b) If the electric potential is uniformly zero in some region of space, the electric field must also be zero in that region 1. true 2. false Enter (143 points) 0 attempt(s) made (maximum allowed for credit - 1) (c) If the electric potential is zero at a point, the electric field must also be zero at that point 1. otrue 2. false Enter (143 points) 0 attempt(s) made (maximum allowed for credit - 1) (d) Electric field lines always point toward regions of lower potential 1. true 2. false Enter (143 points] 0 attempt(s) made (maximum allowed for credit - 1) (e) The value of the electric potential can be chosen to be zero at any convenient point 1. true 2. false Enter (1.43 points) 0 attempt(s) made (maximum allowed for credit - 1) (f) In electrostatics, the surface of a conductor is an equipotential surface 1. otrue 2. false Enter 11.43 points) 0 attempt(s) made (maximum allowed for credit = 1) (g) Dielectric breakdown occurs in air when the potential is 3 x 106 v.

Answer 1

Consider a conducting spherical shell with Q in the middle, -Q on the inside of the shell and Q on the outside of the shell

The electric field is zero within the shell because there is no current, but the potential of the shell is not zero. (1) false

(2) true - if the potential is zero at that point, no work is done in moving a charge around at that point so the field must be zero

(3) false - if two charges are at +-x, one can bring a charge in from infinity and do no work, but the field is not zero at that point

(4) true - Electric field lines point towards regions of a lower potential

(5) false - electric potential is usually chosen zero at infinity

V = K Q / R and E = K Q / R^2