l The centres of two metal spheres of radius 15 cm are 48 cm apart on the x-axis. The spheres are initially neutral, but a charge q is transferred from one sphere to the other, creating a potential difference between the spheres of 100 V. A proton is released from rest at the surface to the positively charged sphere and travels to the negatively charged sphere. At what speed does the proton strike the negatively charged sphere? 2 Three identical charges Q are at the corners of an equilateral triangle of side L. The charges are released one at a time, proceeding clockwise around the triangle. Each charge is allowed to reach its final speed a long distance from the triangle before the next charge is released. What is the final kinetic energy of (a) the first charge released (b) the second charge released (c) the third charge released 3 Three capacitors are connected in a triangular network as shown. Find the equivalent capacitance across terminals b and c. 0 c1 CZ a 03 b 4 Three capacitors are connected as shown. Find + C1: 3,L(F 200 V :l: 03: 14 MF C2: 19pF (a) the total equivalent capacitance between the terminals (b) the the charge stored on each capacitor (c) the total stored energy 5 The membrane of the axon of a nerve cell is a thin cylindrical shell of radius r = 10'5 m, length L = 0.1 m and wall thickness d = 10'8 m. The membrane has a positive charge on one side and a negative charge on the other and acts as a parallel plate capacitor of area A = 2an and separation d. Its dielectric constant is about K=2.8 Find (a) the capacitance of the membrane. (b) If the potential difference across the membrane is 65 mV, find the charge on each side of the membrane and (c) the electric field through the membrane