2a mass of 15 kg of air in a piston–cylinder device is heated from 25 to 95°c by passing current through a resistance heater inside the cylinder. the pressure inside the cylinder is held constant at 300 kpa during the process, and a heat loss of 60 kj occurs. determine the electric energy supplied, in kwh

0.2338KWh

Explanation:

Given

mass of air=15kg

Initial Temperature

Final Temperature

pressure is constant 300 KPa

heat loss =60 KJ

Enthalpy at

Enthalpy at

and for 15 kg air

Thererfore net heat input=

                                          =784.35+60=844.35KJ

                                          =

trig 15.3 cos

hypothesising or postulating