Which of the following statements is true concerning the induced current in a coil of wire for a magnet approaching or moving away from the coil? a. The induced magnetic field repels an approaching magnet.
b. The induced magnetic field attracts a departing magnet.
c. The induced magnetic field always opposes the motion of the magnet.
d. All of the above statements are correct.

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.