Embibe Experts Solutions for Chapter: Thermodynamics, Exercise 1: Exercise-1

The temperature-entropy diagram of a reversible engine cycle is given in the figure. Its efficiency is 

An ideal gas heat engine exhausting heat at $77°\mathrm{C}$ does not have a $30\%$ efficiency. It must take the heat at

Efficiency of carnot engine is $100\%$ if

The efficiency of Carnot's engine operating between reservoirs maintained at temperatures $27°\mathrm{C}$ and $123°\mathrm{C},$ is

A Carnot engine operates between $227 °\mathrm{C}$ and $27 °\mathrm{C}$. The efficiency of the engine will be

A Carnot's engine is made to work between $200 °\mathrm{C}$ and $0 °\mathrm{C}$ first and then between $0 °\mathrm{C}$ and $-200 °\mathrm{C}$. The ratio of efficiencies of the engine in the two cases is

If an ideal flask containing hot coffee is shaken, the temperature of the coffee will:

A heat engine employing a Carnot cycle with an efficiency of $\eta =10\%$ is used as a refrigerating machine, the thermal reservoirs being the same. The refrigerating efficiency is