1. Two alpha particles (helium nuclei), each consisting of two protons and two neutrons, have an electrical potential energy of 6.32 × 10-19 J. What is the distance between these particles at this time?
2. Two charges are located along the x-axis. One has a charge of 6.4 mC, and the second has a charge of -3.2 mC. If the electrical potential energy asso- ciated with the pair of charges is -4.1 × 10-2 J, what is the distance between the charges?
3. In a charging process, 1013 electrons are removed from a metal sphere and placed on a second sphere that is initially uncharged. Then the elec- trical potential energy associated with the two spheres is found to be -7.2 × 10-2 J. What is the distance between the two spheres?
4. A charge moves a distance of 2.0 cm in the direction of a uniform electric field having a magnitude of 215 N/C. The electrical potential energy of the charge decreases by 6.9 × 10-19 J as it moves. Find the magnitude of the charge on the moving particle. (Hint: The electrical potential energy depends on the distance moved in the direction of the field.)