Question

This metal conductor is negatively charges. (Assume this is a cross-section of a conductor)

A. Mark where the electrons would be on the conductor with minuses (-).

B. Sketch the electric field lines (solid) around the conductor, and sketch 2 equipotential line (dotted) around the conductor.

C. Would the potentials that your equipotential lines are representing be positive or negative voltages?

D. Which equipotential line would have a higher magnitude for its voltage (higher number not counting the sign)? (the one closer to the conductor or farther?)

E. If you moved an electron from a spot on the equipotential line closest to the conductor, to a spot on the equipotential line farther from the conductor, would the work you did be positive or negative? Explain.

Answer 1

A. all the excess -ve charge would moves to the surface of the conductor

B. Electric field lines would be towards the conductor., the qevi potential lines are parallel to the surface as shown.

C. The potential is -ve as the charge is -ve (-kq/r)

D. the magnitude of the potential nearer to the surface is higher as r is less

E> when an electron is moved away from the conductor work done is -ve. Electric force on the electron is -ve and the field force pushes the electron away and work is done by the field. Hence work done is -ve.