BCECE Medical BCECE Medical Solved Papers-2001

  • question_answer
    An ideal Carnot engine whose efficiency is 40% receives heat at 500 K. If the efficiency is to be 50% the intake temperature for this same exhaust temperature is :

    A)  600 K         

    B)  800 K

    C)  900 K         

    D)  1000 K

    Correct Answer: A

    Solution :

    The efficiency of a Carnot engine operatic between temperatures \[{{T}_{1}}\]and \[{{T}_{2}}\] is given by                 \[\eta =1-\frac{{{T}_{2}}}{{{T}_{1}}}\] where   \[{{T}_{1}}=\] source temperature                 \[{{T}_{2}}=\] sink temperature                 In 1st, case :                 \[\frac{40}{100}=1-\frac{{{T}_{2}}}{500}\] or            \[\frac{{{T}_{2}}}{500}=1-0.4=0.6\] or            \[{{T}_{2}}=0.6\times 500=300\,K\] In 2nd case :                 \[\frac{50}{100}=1-\frac{300}{T_{1}^{}}\] or            \[\frac{300}{T_{1}^{}}=1-0.5\,=0.5\] or            \[T_{1}^{}=\frac{300}{0.5}=600\,K\] Note: The efficiency of Carnot reversible engine is independent of the working substance and depends only on the absolute temperatures of the sink and the source.


You need to login to perform this action.
You will be redirected in 3 sec spinner