As the temperature increases, the thermal conductivity of a gas

Match Group $$A$$ with Group $$B$$

Group-A
$$P:$$$$\,\,\,\,\,\,\,$$ Biot number
$$Q:$$$$\,\,\,\,\,\,\,$$ Grashof number
$$R:$$$$\,\,\,\,\,\,\,$$ Prandtl number
$$S:$$$$\,\,\,\,\,\,\,$$ Reynolds number

Group-B
$$1:$$$$\,\,\,\,\,\,\,$$ Ratio of buoyancy to viscous force
$$2:$$$$\,\,\,\,\,\,\,$$ Ratio of inertia force to viscous force
$$3:$$$$\,\,\,\,\,\,\,$$ Ratio of momentum to thermal diffusivities
$$4:$$$$\,\,\,\,\,\,\,$$ Ratio of internal thermal resistance to boundary layer thermal resistance

Two infinite parallel plates are placed at a certain distance apart. An infinite radiation shield is inserted between the plates without touching any of them to reduce heat exchange between the plates. Assume that the emissivities of plates and radiation shield are equal. The ratio of the net heat exchange between the plates with and without the shield is

The precedence relations and duration (in days) of activities of a project network are given in the table. The total float (in days) of activities $$e$$ and $$f,$$ respectively, are