In 1 st case, Carnot engine operates between temperatures 300 K and 100 K . In 2 nd case, as shown in the…

In 1st  case, Carnot engine operates between temperatures 300 K and 100 K. In 2nd  case, as shown in the figure, a combination of two engines is used. The efficiency of this combination (in 2nd  case) will be :

  1. same as the 1st  case
  2. always greater than the 1st  case
  3. always less than the 1st  case
  4. may increase or decrease with respect to the 1st  case

Solution

The efficiency of a Carnot engine operating between two temperatures is given by η=1-TLTH

For the first case : η=1-100300=23

For the second case : ηnet =η1+η2-η1η2

η1=1-200300=13

η2=1-100200=12

ηnet =13+12-16=23

η(first case)=η(second case)

Asked in: JEE Main 2022 (27 Jul Shift 2)

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