Asolid copper sphere whose raclius is 10 em has a very thin surface contin of nickel some of the nickel atoms are radioactive and emit an electron with each decay. due to the geometry of the situation, half of these electrons enter the copper sphere, each depositing 100 kev of energy there. the other half of the electrons escape, each carrying away a charge of c. the nickel coating has an activity of 10 mci (millicuries) -3.70 x 10 radioactive decays per second. the sphere is hung from a long, nonconducting string and isolated from its surroundings. (a) how long will it take for the potential of the sphere to increase lw 1000 v7 note: 1 ev = 1.602 x 1019 joules (b) how long will it take for the temperature of the sphere to increase by 5.0° c due to the energy deposited by the electrons? the heat capacity of the sphere is 14.3 j/k.