NEET Physics Thermodynamical Processes NEET PYQ-Thermodynamical Processes

An ideal gas heat engine operates in a Carnot cycle between \[{{227}^{o}}C\] and \[{{127}^{o}}C\]. It absorbs 6 kcal at the higher temperature. The amount of heat (in kcal) converted into work is equal to:                     [AIPMT 2003]

A) 1.6

B)                  1.2

C) 4.8

D)      3.5

Correct Answer: B

Solution :

The efficiency of heat engine is \[\eta =1-\frac{{{T}_{2}}}{{{T}_{1}}}\]

or \[\frac{W}{{{Q}_{1}}}=1-\frac{{{T}_{2}}}{{{T}_{1}}}\]

Here, \[{{Q}_{1}}=\] heat absorbed from the source of heat = 6 kcal

\[{{T}_{1}}=\] temperature of source

\[=227+273=500\text{ }K\]

and \[{{T}_{2}}=\] temperature of sink

\[=127+273=400\text{ }K\]

Hence, \[\frac{W}{6}=1-\frac{400}{500}\]

or \[\frac{W}{6}=\frac{100}{500}\]

or \[W=1.2\text{ kcal}\]

Thus, amount of heat converted into work is 1.2 kcal.