4. a spherical shell with outer radius b surrounds a charge-free cavity of radius a < b. if the shell contains a charge density given by   0 3 2 c/m for 0 elsewhere v v arb r r           a. find the electric field e in all regions b. determine the electric potential v in all regions c. determine the electrostatic energy stored for r  a, a  r  b, and r  b.

9. an object is moved from the outdoors, which is at a temperature of 100 ºf, to a room at a temperature of 70 º f. what happens to the object when it’s placed in the room with a lower temperature? the object gives off more energy than it absorbs until it reaches a new lower thermal equilibrium where the amount of energy absorbed and given off is the same. the object gives off the same amount of energy as it absorbs until it reaches a new lower thermal equilibrium where the amount of energy given off is greater than the amount of energy it absorbs. the object gives off more energy than it absorbs until it reaches a new higher thermal equilibrium where the amount of energy absorbed and given off is the same. the object absorbs more energy than it gives off until it reaches a new lower thermal equilibrium where the amount of energy absorbed and given off is the same.