Two identical metal blocks $$L$$ and $$M$$ (specific heat $$=0.4$$ $$kJ/kg.K$$), each having a mass of $$5$$ $$kg,$$ are initially at $$313$$ $$K.$$ A reversible refrigerator extracts heat from block $$L$$ and rejects heat to block $$M$$ until the temperature of block $$L$$ reaches $$293$$ $$K.$$ The final temperature (in $$K$$) of block $$M$$ is ___________.

An amount of $$100$$ $$kW$$ of heat is transferred through a wall in steady state. One side of the wall is maintained at $${127^ \circ }C$$ and the other side at $${27^ \circ }C$$. The entropy generated $$($$in $$W/K)$$ due to the heat transfer through the wall is _____________

An ideal gas of mass $$m$$ and temperature $${T_1}$$ undergoes a reversible isothermal process from an initial pressure $${P_1}$$ to final pressure $$P{}_2.$$ The heat loss during the process is $$Q$$. The entropy changes $$\Delta S$$ of the gas is

In an experimental set-up, air flows between two stations $$P$$ and $$Q$$ adiabatically. The direction of flow depends on the pressure and temperature conditions maintained at $$P$$ and $$Q$$. The conditions at station $$P$$ are $$150$$ $$kPa$$ and $$350$$ $$K.$$ The temperature at station $$Q$$ is $$300$$ $$K.$$ The following are the properties and relations pertaining to air:

Specific heat at constant pressure, $$${C_p} = 1.005\,\,kJ/kg\,\,K;$$$
Specific heat at constant volume, $$${C_v} = 0.718\,\,kJ/kg\,\,K;$$$
Characteristic gas constant, $$R=0.287$$ $$kJ/kgK.$$
Enthalpy $$h = {C_p}T,$$
Internal energy, $$u = {C_v}T.$$

If the air has to flow from station $$P$$ to station $$Q,$$ the maximum possible value of pressure in $$kPa$$ at station $$Q$$ is close to