Match List - $${\rm I}$$ with List - $${\rm II}$$

List - $${\rm I}$$
$$A.$$ Cetane number
$$B.$$ Approach and range
$$C.$$ $${\left( {{{\delta T} \over {\delta P}}} \right)_h} \ne 0$$
$$D.$$ $$dh = {c_p}\,\,dT,$$ even when pressure varies

List - $${\rm II}$$
$$1.$$ Ideal gas
$$2.$$ Vander Waals gas
$$3.$$ $$S.\,{\rm I}.$$ engine
$$4.$$ $$C.\,{\rm I}.$$ engine
$$5.$$ Cooling towers
$$6.$$ Heat exchangers

For reversible adiabatic compression in a steady flow process, the work transfer per unit mass is

A solar energy based heat engine which receives $$80$$ $$kJ$$ of heat at $${100^ \circ }C$$ and rejects $$70$$ $$kJ$$ of heat to the ambient at $${30^ \circ }C$$ is to be designed. The thermal efficiency of the heat engine is

For two cycles coupled in series, the topping cycle has an efficiency of $$30\% $$ and the bottoming cycle has an efficiency of $$20\% $$. The overall combined cycle efficiency is