The temp variation under steady heat conduction across a composite slab of two materials with thermal conductivies $${K_1}$$ and $${K_2}$$ is shown in fig. then, which one of the following statements holds?

For a current carrying wire of $$20$$ $$mm$$ diameter and having $$k=0.5W/mK$$ is exposed to air $$\left( {h = 20W/{m^2}K} \right),$$ maximum heat dissiption occurs when thickness of insulation is

Match the property with their units

Property
$$A.$$ Bulk modulus
$$B.$$ Thermal conductivity
$$C.$$ Heat transfer coefficient
$$D.$$ Heart flow rate

Units
$$1.$$ $$W/s$$
$$2.$$ $$N/{m^2}$$
$$3.$$ $$N/{m^3}$$
$$4.$$ $$W$$
$$5.$$ $$W/mK$$
$$6.$$ $$W/{m^2}K$$