Choose the correct statement concerning electric fields lines

Question

A. Field lines are close together where the field is strong

B. Field lines are always parallel to equipotential lines

C. Field lines point away from negative charges

D. Field lines are close together where the field is weak

Answer 1

A. is correct.

Think of the picture of a single positive charge.

The field lines are emanating in all directions getting more and more

separated with distance as the fields gets weaker.

B. is wrong.

Field lines are always perpendicular to equipotential lines.

Imagine a charge moving along an equipotential line.

By definition of "equipotential" its potential energy does not change.

Therefore the field cannot be making any work.

Therefore the force of the field must be perpendicular to the direction of movement.

C. is wrong.

The convention is for field lines to point away from positive changes

and towards negative charges.

D. is wrong.

The same explanation as in A.