## Biot and Nusselt

Describe the physical significance of the Biot and the Nusselt number. (No need to write the equations.)

Hint
In terms of heat transfer, a small Biot number means temperature is uniform within the object and it is a lumped system.
Hint 2
The Nusselt number is a dimensionless temperature gradient at the surface.
Small Biot number means temperature is uniform within the object and it is a lumped system.
$$Bi=\frac{thermal\: resistance\: of\: a\: solid\: to\: conduction\: heat\: transfer}{external\: thermal\: resistance\: of\: heat\: transfer}$$$Nusselt number is a dimensionless temperature gradient at the surface. $$Nu=\frac{convection\: heat\: transfer}{conduction\: heat \:transfer}$$$
Small Biot number means temperature is uniform within the object and it is a lumped system.
$$Bi=\frac{thermal\: resistance\: of\: a\: solid\: to\: conduction\: heat\: transfer}{external\: thermal\: resistance\: of\: heat\: transfer}$$$Nusselt number is a dimensionless temperature gradient at the surface. $$Nu=\frac{convection\: heat\: transfer}{conduction\: heat \:transfer}$$$