calorific value

heat energy

lower calorific value

higher calorific value

petrol engine

diesel engine

reversible engine

irreversible engine

pressure and temperature

temperature and volume

heat and work

all of these

possible

impossible

easy

none of these

All the reversible engines have the same efficiency.

All the reversible and irreversible engines have the same efficiency.

Irreversible engines have maximum efficiency.

All engines are designed as reversible in order to obtain maximum efficiency.