(i) state three energy transfer mechanisms within a star for each mechanism, state whether it is significant in the core and in the outer regions of the sun. (ii) sketch the internal structure of a star with 0.08 mo < m < 0.5mo. state the source(s) of the energy. label the source(s) of energy and of energy transfer

Carbon is allowed to diffuse through a steel plate 15 mm thick. the concentrations of carbon at the two faces are 0.65 and 0.30 kg c/m^3 fe, which are maintained constant. if the preexponential and activation energy are 6.2 x 10-7 m2 /s and 80,000 j/mol, respectively, compute the temperature at which the diffusion flux is 1.43 x 10^-9 kg/m^2 -s.