A heat engine having an efficiency of $$70\% $$ is used to drive a refrigerator having a coefficient of performance of $$5.$$ The energy absorbed from low temperature reservoir by the refrigerator for each $$kJ$$ of energy absorbed from high temperature source by the engine is

A solar collector receiving solar radiation at the rate of $$0.6$$$$kW/{m^2}$$ transforms it to the internal energy of a fluid at an overall efficiency of $$50\% $$. The fluid heated to $$350$$ $$K$$ is used to run a heat engine which rejects heat at $$313$$ $$K.$$ If the heat engine is to deliver $$2.5$$ $$kW$$ power, then minimum area of the solar collector required would be

A steel billet of $$2000$$ $$kg$$ mass is to be cooled from $$1250$$ $$K$$ to $$450$$ $$K.$$ The heat released during this process is to be used as a source of energy. The ambient temperature is $$303$$ $$K$$ and specific heat of steel is $$0.5$$ $$kJ/kg K.$$ the available energy of this billet is

Consider a steam power plant using a reheat cycle as shown. Steam leaves the boiler and enters the turbine at $$4$$ $$MPa,$$ $${350^ \circ }C$$ $$\left( {{h_3} = 3095\,\,kJ/kg} \right).$$ After expansion in the turbine to $$400$$ $$kPa$$ $$\left( {{h_4} = 2609\,\,kJ/kg} \right)$$, the steam is reheated to $${350^ \circ }C$$ $$\left( {{h_5} = 3170\,kJ/kg} \right),$$ and then expanded in a low pressure turbine to $$10$$ $$kPa$$ $$\left( {{h_6} = 2165\,kJ/kg} \right).$$

The thermal efficiency of the plant neglecting pump work is