Given below are two statements: 
Assertion (A): It is not possible for a system, unaided by an external agency to transfer heat from a body at a lower temperature to another at a higher temperature.
Reason (R): It is not possible to violate the second law of thermodynamics.
  
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Second Law of Thermodynamics |
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Given below are two statements: 
Assertion (A): The temperature of the surface of the sun is approximately \(6000\) K. If we take a big lens and focus the sun rays, we can produce a temperature of \(8000\) K.
Reason (R): This is the highest temperature that can be produced according to the second law of thermodynamics.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Second Law of Thermodynamics |
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Consider a cycle followed by an engine (figure). 


1 to 2 is isothermal,
2 to 3 is adiabatic,
3 to 1 is adiabatic.
Such a process does not exist, because:

(a) heat is completely converted to mechanical energy in such a process, which is not possible.
(b) In this process, mechanical energy is completely converted to heat, which is not possible.
(c) curves representing two adiabatic processes don’t intersect.
(d) curves representing an adiabatic process and an isothermal process don't intersect.

Choose the correct alternatives:

1. (a), (b) 2. (a), (c)
3. (b), (c) 4. (c), (d)
Subtopic:  First Law of Thermodynamics | Second Law of Thermodynamics |
 56%
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The second law of thermodynamics says:
1. the efficiency of a heat engine can be unity.
2. the heat released to the cold reservoir can be made zero.
3. coefficient of performance can never be infinite for refrigerators.
4. none of the above.
Subtopic:  Second Law of Thermodynamics |
 61%
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