Heat Engines

In which part , air and gas(petrol) mixes in internal combustion engine?

The efficiency of a heat engine increases by $20\%$ when temperature of source is increased by $20\%$ and temperature of sink is decreased by $20\%$ simultaneously. The old efficiency of the engine is

A car engine has a power of $20 \mathrm{kW}$. The car makes a roundtrip of 1 hour. If the thermal efficiency of the engine is $40\%$ and the ambient temperature is $300 \mathrm{K}$. The energy generated by fuel combustion is

An idealized diesel engine operates in a cycle known as air standard diesel cycle as shown. Fuel is sprayed into the cylinder at the the point of maximum compression $B$. Combustion occurs during expansion $BC$.

The efficiency is always

State the uses of heat engine?

Explain why the efficiency of a heat engine can not be $100\%$

A heat engine whose sink is at $290 \mathrm{K}$ has an efficiency of $30\%$. By how much the temperature of the source be increased to have efficiency equal to $50\%,$keeping the sink temperature constant?

The efficiency of a heat engine is '$\eta$' and the coefficient of performance of a refrigerator is '$\beta$'. Then

One mole of ideal monoatomic gas is taken along a cyclic process as shown in the figure. Process
1 → 2 shown is 1/4^th part of a circle as shown by dotted line process 2 → 3 is isochoric while
3 → 1 is isobaric. If efficiency of the cycle is n% where n is an integer. Find n.

The thermodynamic efficiency of cell is given by