Air is contained in a sealed vertical piston-cylinder apparatus fitted with an electrical resistor. The atmospheric pressure above the piston is 1.01 bar. The piston has a mass of 45.36 kg and a surface area of 0.093 m2. Electric current passes through the resistor, and the volume of the air slowly increases by 0.045 m^3 while its pressure remains constant. The mass of the air is 0.27 kg, and its specific internal energy increases by 41.86 kJ/kg. The air and piston are at rest initially and finally. The piston and cylinder are made of ceramic, which is a good insulator. Friction between the piston and cylinder wall can be ignored, and the local acceleration of gravity is g= 9.8m/s^2. Required:
Determine the heat transfer from the resistor to the air, in kJ, for a system consisting of the air alone.