If the temperature of a source increases, then the efficiency of a heat engine

If the temperature of the sinkis decreased, then the efficiency of heat engine

If the temperature of the source is increased, the efficiency of the carnot engine

For which combination of working temperatures of the source and sink, the efficiency of Carnot's heat engine is maximum?

On tripling the absolute temperature of the source, the efficiency of a Carnot.s heat engine becomes double that of the initial efficiency. Then the initial efficiency of the engine is ________

A Carnot engine has an efficiency of 30% when the temperature of sink is 56^@C . How should the temperature of source be increased if the engine efficiency is to be increased to 80% ?

The temperature of the sink of a carnot engine is 300 K and its efficiency is 40 %. Find the decrease in temperature of the sink required to increase the efficiency of the engine to 50% keeping temperature of the source to be constant.

A Carnot engine, whose temperature of the source is 400K receives 200 calories of heat at this temperature and rejects 150 calaroies of heat to the sink. What is the temperature of the sink? Also, calculate the efficiency of the engine