A cylindrical electrical transformer of radius 40mm is cooled by 1mm thick annular brass fins of outer radius 200mm, as shown in Figure 2. The transformer is perfectly insulated from the surrounding air except via the fins. The total steady-state output of the transformer per fin is 150 W. The surrounding air is at a temperature of 10C. Calculate: (a) The temperature at the base of each fin. (3 marks) (b) The efficiency of each fin. (3 marks) Clearly explain