The discharge velocity at the pipe exit in figure is

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?

A gas filled tube has $$2$$ $$mm$$ inside diameter and $$25$$ $$cm$$ length. The gas is heated by an electrical wire of diameter $$50$$ microns ($$0.05$$ $$mm$$) located along the axis of the tube. Current and voltage drop across the heating element are $$0.5$$ amps and $$4$$ volts, respectively. If the measured wire and inside tube wall temperatures are $${175^ \circ }C$$ and $${150^ \circ }C$$ respectively, find the thermal conductivity of the gas filling the tube.

Heat transfer coefficients for free convection in gasses, forced convection in gases and vapors, and for boiling water lie, respectively, in the range of