The $$S{\rm I}$$ unit of kinematic viscosity $$\left( \upsilon \right)$$ is :

For the circular tube of equal length and diameter shown in fig below, the view factor $${F_{13}}$$ is $$0.17.$$ The view factor $${F_{12}}$$ in this case will be.

Water (Prandtl number $$=6$$ ) flows over a flat plate which is heated over the entire length. Which one of the following relationship between the hydrodynamic boundary layer thickness $$\left( \delta \right)$$ and thermal boundary layer thickness $$\left( {{\delta _t}} \right)$$ is true

Lumped heat transfer analysis of a solid object suddenly exposed to a fluid medium at a different temp is valid when.