The efficiency of an ideal heat engine (Carnot heat engine) working between the freezing point and boiling point of water is:
1. \(26.8\%\)
2. \(20\%\)
3. \(6.25\%\)
4. \(12.5\%\)

A Carnot engine whose sink is at \(300~\mathrm{K}\) has an efficiency of \(40\)%. By how much should the temperature of the source be increased to increase its efficiency by \(50\)% of its original efficiency?

An ideal gas heat engine operates in a Carnot cycle between 227ºC and 127ºC. It absorbs 6 × 10⁴ cals of heat at higher temperatures. The amount of heat converted to work will be?
1. 4.8 × 10⁴ cals
2. 2.4 × 10⁴ cals
3. 1.2 × 10⁴ cals
4. 6 × 10⁴ cals