The following four figures have been drawn to represent a fictitious thermodynamic cycle, on the $$P$$-$$v$$ and $$T$$-$$S$$ plates

According to the first law of thermodynamics, equal areas are enclosed by

An industrial heat pump operates between the temperatures of $${27^ \circ }C$$ and $$ - {13^ \circ }C.$$ The rates of heat addition and heat rejection are $$750$$ $$W$$ and $$1000$$ $$W,$$ respectively. The $$COP$$ for the heat pump is

Consider a refrigerator and a heat pump working on the reversed Carnot cycle between the same temperature limits. Which of the following is correct?

In the case of a refrigeration system undergoing an irreversible cycle, $$\oint {{{SQ} \over T}} $$ is _____________$$\left( { < 0/ = 0/ > 0} \right)$$