Since energy can be produced both through fission and fusion, why do nuclear energy plants only use fission to create energy? a. fission reactions occur at much lower temperatures than fusion reactions. b. the fission process creates less nuclear waste than the fusion process c. fission reactions create more energy than fusion reactions. d. the parent nuclei of fission reactions are more readily available than fusion parent nuclei.

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.