Second Law of Thermodynamics — MCQ Practice

A Carnot engine operates between $227^\circ\text{C}$ and $27^\circ\text{C}$. It absorbs $6 \times 10^4\,\text{J}$ of heat at the higher temperature. The amount of heat rejected to the cold reservoir is:

A refrigerator has a coefficient of performance (COP) of 5. If it rejects $120\,\text{J}$ of heat to the surroundings in one cycle, the work done on the working substance is:

Which of the following statements is a direct consequence of the Kelvin-Planck statement of the Second Law of Thermodynamics?

An ideal gas undergoes a reversible isothermal expansion. What can be said about the change in entropy of the gas and the universe?

A heat pump is used to maintain a house at $20^\circ\text{C}$ when the outside temperature is $0^\circ\text{C}$. If the heat pump operates with maximum theoretical efficiency, what is its coefficient of performance (COP)?

Which of the following processes is always accompanied by an increase in the entropy of the universe?