## Lakshya Education MCQs

Question: Now Tony settles upon a Carnot engine. Calculate the efficiency of the Carnot engine if the temperature it operates between are 350 K and 250 K.

Options:
 A. 27 B. 57 C. 37 D. 47 E. along the line CD
: A

The efficiency of a Carnot engine is given by the formula ηH.E=1TLTH Substituting for known values we get ηH.E=1250350=27

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## More Questions on This Topic :

Question 1. An ideal gas in a heat engine executes the cycle shown. Where is the temperature of the gas maximum?

1.    along the line BC
2.    at point B
3.    at point C
4.    at point D
5.    along the line CD
: C

Temperature is maximum at point C. for ideal gas, pV = NRT, so T is max, when pV is max, which corresponds to the point furthest from the origin.
Question 2. Again, the engine does 41,000 J of useful work. If it sinks 9,000 J of energy in the form of heat to its cold reservoir, what is the efficiency of this engine?
1.    18%
2.    64%
3.    82%
4.    40%
: C

QH=W+QL=50000J e=EnergyoutputEnergyinput=WQH=41000J50000J=82or82%
Question 3. The figure here shows five paths traversed by a gas on a P-V diagram. Rank the paths according to the change in internal energy of the gas, greatest first.

1.    5 > 4 = 3 > 2 = 1
2.    5 > 4 = 3 > 1 = 2
3.    4 = 3 > 5 > 1 = 2
4.    5 > 4 = 3 = 2 = 1
5.    along the line CD