A steak which is 2.5cm thick is cooking in a frying pan which has a 4mm thick base. The electric element used to heat the pan is turned to a level such that the bottom surface of the pan sitting on the element is at 120°C. The meat is deemed safe to eat when the temperature at the top of the steak has reached 70°C. The steak has a moisture content of 70%. The frying pan is made of cast iron and has a thermal conductivity of 55 J/s.m.K. The temperature of the steak must be at a safe level within 8 minutes.

a) Calculate the thermal conductivity of the steak.

b) What is the rate of heat flux that will be achieved when the steak is safely cooked?

c) What is the temperature at the interface between the pan and the steak?