Q39 / 268 · NTA Abhyas (NEET) 2020 · Physics · Thermodynamics

In Carnot engine, efficiency is 40% at hot reservoir temperature T. For efficiency 50%, what will be the temperature of hot reservoir?

  • A
    2T5
  • B
    6T
  • Correct answer
    C
    6T5
  • D
    T5

Solution

The efficiency η=work doneheat input=WQ

η=1-T2T1

Where, T2= temperature of sink

And T1= temperature of hot reservoir

40100=1-T2T1

⇒   T2T1=0.6

⇒    T2=0.6T1

Now, 50100=1-T2T1′⇒T2T1′=0.5

0.6T1T1′=0.5

⇒    T1′=0.60.5T1

⇒    T1′=65T1

⇒    T1′=65T ∵  T1=T

Hence, the correct answer is option: 'C'.

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