The current during electrical oscillations in the oscillating circuit changes over time depending on the dependence I(t) =Imax sin(8πt / t0 +π/5), t0-constant, Imax - amplitude value of current. Find the period of oscillations. Write an expression for the time change of charge. Determine the amplitude value of the charge.

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.