1. A proton with an initial speed of 600,000 m/s is brought to rest by an electric field.

Part A - What was the potential difference that stopped the proton?

Part B - What was the initial kinetic energy of the proton, in electron volts?

2. Moving a charge from point A , where the potential is 300 V , to point B , where the potential is 170 V , takes 4.9×10^-4 J of work.

 Part A - What is the value of the charge? 

3. A +19 nC charge is at the origin.

Part A - How much farher from the charge is the 2000 V equipotential surface than the 3000 V surface?

4. A 20 nC charge is moved from a point where V = 210 V to a point where V = -50 V .

Part A - How much work is done by the force that moves the charge?