# A Carnot's engine working between 400 K and 800 K has a work output of 1200 J per cycle.

A Carnot's engine working between 400 K and 800 K has a work output of 1200 J per cycle. The amount of heat energy supplied to the engine from the source in each cycle is

(1) 1800 J (2) 2400 J (3) 3200 J (4) 1600 J

$${W\over Q_{in}}=1-{T_2\over T_1}=1-{1\over2}={1\over2}$$
$${1200\over Q_{in}}={1\over2}$$