Question

A proton is given a speed of 30 km/s and sent towards a charge of 1 nC which is fixed in place 30 m away.

a) What is the value of the potential 30 m away from the 1 nC charge?

b) What is the closest that the proton gets to the 1 nC charge?

(c) If we do this with an electron moving at 30km/s and a -1nC charge 30m away, does the electron get closer to the -1 nC charge than the proton gets to the +1 nC charge? You may answer this either with a calculation or a conceptual argument.

(d) Sketch equipotential lines for the case of the proton near the 1nC charge. Be sure to indicate the potential close to each individual charge, at moderate distances from the charges and also very far from both of them.

Answer 1