Calculate the number of 12 V batteries (capacity 120 Ah) needed to run a 3 kW DC motor that operates in 240 V. How many hours th
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Answer:
<em>Heat rejected to cold body = 3.81 kJ</em>
Explanation:
Temperature of hot thermal reservoir Th = 1600 K
Temperature of cold thermal reservoir Tc = 400 K
<em>efficiency of the Carnot's engine = 1 - </em><em> </em>
eff. of the Carnot's engine = 1 -
eff = 1 - 0.25 = 0.75
<em>efficiency of the heat engine = 70% of 0.75 = 0.525</em>
work done by heat engine = 2 kJ
<em>eff. of heat engine is gotten as = W/Q</em>
where W = work done by heat engine
Q = heat rejected by heat engine to lower temperature reservoir
from the equation, we can derive that
heat rejected Q = W/eff = 2/0.525 = <em>3.81 kJ</em>