Question

A heat engine uses resistors to boil water as part of its operation." 27 A, 141, and 14 12 connected in series. The resistors are What is the equivalent resistance of the three resistors? water as part of its operation. There are 3 resistors with resistances ced in series. The resistors are connected to a 180 V power source, What is the current through the 14 A resistor? А What is the voltage across the 14 A resistor? v How much electric power is dissipated in the 14 A resistor? W The engine turns water into steam, and then heats the steam up to 220 °C. How much heat do you have to add to 1.5 kg of water, starting at 25 °C, to turn it completely to steam at 220 °C? (Cwater = 4.100 kJ/kg.°C, Csteam = 1.90 kJ/kg.°C, Lfusion = 334 kJ/kg, Lvaporization = 2260 kJ/kg) The engine extracts 1300 k) of heat from the steam each cycle, and does 275 kJ of work. What is the engines efficiency?

Answer 1

272 1452 lar 180V To equivalent Resistance of the circuit R = 27+4+14=552 o The current through 142 as I = È I= 180 = 3.27 A o voltage across 142 is X4 V = 14xI V = 1443.27= 45.78 volt o eletric power déssipited in 1482 Resistor is p-I'R = 3.278x14 = 149.7 w • Total heat required is Q=mcw ( 1000-250) + m Irap t m Cstean (220 -100°) il = 5 4.186 X 75 + 2260 + J.90x1201 9 - 4202.9 KJ o efficiency of engine m= 1- Work 275 heat input not 1300+245)\/00% = 82.5%