Practice on Potential energy and potential difference 1-A proton is released from rest in a uniform electric field with a magnitude of 8.0 × 104 V/m. If the proton is displaced 0.50 m find : A- The potential difference between the proton’s initial and final positions. B- The change in PE for the proton 2- A charge moves a distance of 2.0 cm in the direction of a uniform electric field whose magnitude is 215 N/C.As the charge moves, its electrical potential energy decreases by 6.9 10-19 J. Find the charge on the moving particle. What is the potential difference between the two locations? 3- A charged particle gains 3.1 × 10−12 J of potential energy when it moves 4.7 cm through a uniform electric field. The potential difference across this distance is −73 V. a. What is the magnitude of the electric field? b. What is the magnitude of the charge on the particle?