The efficiency of a Carnot's engine is \(100 \%\) only when
The efficiency of a Carnot's engine is \(100 \%\) only when
ideal gas is used as a working substance
temperature of the sink is equal to absolute zero
source temperature is equal to the temperature of the sink
source temperature is equal to absolute zero
Solution
The efficiency of Carnot's engine is given as
\(\eta=1-\frac{T_2}{T_1}\) ...(i)
where, \(T_1=\) temperature of source
and \(T_2=\) temperature of sink.
For \(100 \%\) efficiency, \(\eta=1\)
\(\therefore\) From Eq. (i), we get
\(1=1-\frac{T_2}{T_1} \Rightarrow \frac{T_2}{T_1}=0 \Rightarrow T_2=0\)
Hence, temperature of \(\operatorname{sink} T_2\) is equal to absolute zero.