(a) Two point charges with q1 = +3.5 x 10 C and 92 = -4.5 x 10- C are initially separated by a distance of r = 2.5 x 10-4m. (i) How much energy is required to double their separation? (ii) What is the electric potential at the point midway between the two charges when their separation is 2r? (b) A uniform electric field of magnitude 1.0 x 102 NC- exists between two conducting plates, one of which is positively charged and the other of which is negatively charged. The plates are 1.0 x 10-2 m apart. (i) Calculate the magnitude of the potential difference between the plates. (ii) If a proton is moved from the positive plate to the negative plate, what is the magnitude of the change in its electrostatic potential energy? (iii) If this device operates as a capacitor, how is it able to store electrostatic potential energy