A Carnot engine working between 300 K and 400 K has 800 J of useful work. The amount of heat energy supplied to the engine from the source is

Question

A Carnot engine working between 300 K and 400 K has 800 J of useful work. The amount of heat energy supplied to the engine from the source is (A) 2400 J (B) 3200 J (C) 1200 J (D) 3600 J

Tardigrade Admin · Accepted Answer

η =( text Work done / text Heat supplied ) =(T1-T2/T1)=(W/Q1) W =800 J , T1=400 K , T2=300 K On substitution the values (800/Q1) =(400-300/400) =(100/400)=(1/4) Q1 =800 × 4=3200 J

Q. A Carnot engine working between $300 K$ and $400 K$ has $800 J$ of useful work. The amount of heat energy supplied to the engine from the source is

2400 J

3200 J

1200 J

3600 J

$η = \frac{Work done}{Heat supplied}$
$= \frac{T _{1} - T _{2}}{T _{1}} = \frac{W}{Q _{1}}$
$W = 800 J, T_{1} = 400 K, T_{2} = 300 K$
On substitution the values
$\frac{800}{Q _{1}} = \frac{400 - 300}{400}$
$= \frac{100}{400} = \frac{1}{4}$
$Q_{1} = 800 \times 4 = 3200 J$

Q. A Carnot engine working between 300K and 400K has 800J of useful work. The amount of heat energy supplied to the engine from the source is