Which is true? I. It takes positive work to bring like charges together. II. Electric field lines always point in the direction of decreasing electric potential. III. If a negative charge moves in the direction of the electric field, its potential energy decreases

Sentence III

Explanation:

I. It takes positive work to bring like charges together.

Using Coulom law we know that like charges will feel a repulsion force that meen that if we want to put them together we are going againt the force, this means we need a negative work. So is False.

II. Electric field lines always point in the direction of decreasing electric potential.

The elctrical fiels depend on the charge of the particle. So if the particle is positive the field will point always outwart the charge, and if the particle is negative, the electric field will point to the charge. Also, we know that the potential is bigger clouser to the charge, so this sentence is folce when we have a negative charge. So is False.

III. If a negative charge moves in the direction of the electric field, its potential energy decreases

If a negative particle move in the direction of the elctric field in bout cases the potential will decrease. If we have a positive charge the electron will be atracted by the field, How ever the electric fild is pointing in the other direction, for that reason will decrease.