Argon gas enters a converging-diverging nozzle at 60 m/s, 310 °C, and 300 kPa, and it leaves the nozzle at a supersonic velocity. The throat diameter is 3 cm. For Argon R= 208.1 Pa. m3/kg. K; k= 1.667. Determine

When oxygen reacts with hydrogen, it has the capacity to release 29 kilojoules of energy. inside a fuel cell, oxygen reacts with hydrogen to produce 23 kilojoules of useful energy. the rest of the energy is lost as heat. what's the efficiency percentage of the fuel cell?