Water (specific heat, cp = 4.18 kJ/kg.K ) enters a pipe at a rate of 0.01 kg/s and a temperature of 20 C. The pipe, of diameter 50 mm and length 3 m, is subjected to a wall heat flux qw in W/m^2:

If qw = 2500x, where x is m and in the direction of flow (x=0 at the inlet), the bulk mean temperature of the water leaving the pipe in C is A. 42 B. 62 C. 74 D. 104

If qw = 5000 and the convection heat transfer coefficient at the pipe outlet is 1000 W/m^2.K, the temperature in C at the inner surface of the pipe at the outlet is A. 71 B. 76 C. 79 D. 81