Question

The lines show the equipotential contours in the plane of three point charges, Q₁, Q₂, and Q₃. The values of the potentials are in kV as indicated for the +5, 0, and -5 kV contours. The positions of the charges are indicated by the dots.

$prob04a_threeqcontour.gif$

Calculate the external work required to move a negative charge, q= -8e (where e is, as usual, the charge of a proton) from `a' to `b' at constant speed.
(Note: The equipotential lines shown are separated by 1 kV, not 1 V!)

Answer 1

Solutionn Work done by the equipotential lines --(-8e)(-5kV-(5kV)) = 8ex-10kV =8x 1.6x10-"CX-10kV -1.28x10-14J Therefore, extemal work required to move a negative charge is 1.28x10