Why do nuclear power plants use fission rather than fusion to generate electric energy?
A. Fusion requires very high pressure and temperature.
B. A problem might lead to an explosion in a fusion reactor, but not
in a fission reactor.
C. The isotope used in fission is more common than the one used
in fusion.
D. Fission produces less radioactive waste than fusion does.

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

Consider an insulating crystal, made up of layers of atoms. what form would you expect the temperature dependence of the phonon heat capacity to approach at extremely low temperatures if the interlayer coupling is i)very strong (rigid coupling), and ii) very weak. explain.

You can decrease the resistance of a length of wire by