An incompressible fluid flows over a flat plate with zero pressure gradient. The boundary layer thickness is $$1mm$$ at a location where the Reynolds number is $$1000$$. If the velocity of the fluid alone is increased by a factor of $$4,$$ then the boundary layer thickness sat the same location, in $$mm$$ will be

Which one of the following configurations has the highest fin effectiveness?

For an opaque surface, the absorptivity $$\left( \alpha \right),$$ transmissivity $$\left( \tau \right)$$ and reflectivity $$\left( \rho \right)$$ are related by the equation:

Consider two infinitely long thin concentric tubes of circular cross section as shown in the figure. If $${D_1}$$ and $${D_2}$$ are the diameters of the inner and outer tubes respectively, then the view factor $${F_{22}}$$ is given by