The circular plates of a parallel-plate capacitor have a radius of 30 mm. A steady 0.43-mA current is charging the initially uncharged capacitor, and the surface charge on the plates is distributed uniformly. The flat circular surface between the capacitor plates is coaxial and parallel to the plates, and has a radius of 13 mm. Calculate the magnetic field at any point on the circumference of the circular region (in Tesla).

Air enters a gas turbine with two stages of compression and two stages of expansion at 100 kpa and 17°c. this system uses a regenerator as well as reheating and intercooling – the intercooler returns the air to the inlet temperature. the pressure ratio across each compressor is 4 ; 300 kj/kg of heat are added to the air in each combustion chamber; and the regenerator operates perfectly while increasing the temperature of the cold air by 20°c. determine the system’s thermal efficiency. assume isentropic operations for all compressor and the turbine stages and use constant specific heats at room temperature. (0.378)