Question

a) If the potential is taken as zero at an infinite distance from the charges, how can points near the charges also have zero potential?

b) Explain why equipotentials and E field lines must always be perpendicular.

c) Where are the most negative potentials located in the space surrounding several point charges of opposite signs?

d) At a given point in an electric field, does the E vector point toward higher or lower potential?

e) At a given point in an electric field, does the E vector point toward higher or lower potential energy for a positive charge at that point? Explain why.

f) At a given point in an electric field, does the E vector point toward higher or lower potential energy for a negative charge at that point? Explain why.

g) If a positive charge is released from rest in an electric field, will it move toward lower or higher potentials? What if a negative charge is released from rest?

h) If a negative charge is placed in a closed orbit (not necessarily circular) around a single positive charge, is the potential constant everywhere on the orbit? If not, is there any energy quantity that is constant along the entire orbit?

Answer 1

(A) if there are more than one charge of opposite sign then resultant potential may be zero.

(B) V (potential) along equipotential surface is constant. And E is along the rate of changing V . I.e. component of E along the equipotential surface is zero. So E is perpendicular to equipotential surfave.

(C) nearest to most negative charge.

(D) E = -dV/dr

So E is from high potential to lower potential.

(E) Electric field is from higher potential energy to lower potential for positive charge.

(F)E Electric field is from lower to higher potential for a negative charge.

(G) a positive charge move from higher potential to lower potential but a negative charge move from lower potential to higher potential.

(H) If orbit is circular for a point charge then it will be equipotential surface otherwise it will have different potential.

Energy is also constant for a circular orbit. But fir other orbit energy will not be constant.