lumped heat capacity

A small copper ball of $$5$$ $$mm$$ diameter at $$500$$ $$K$$ is dropped into an oil bath whose temperature is $$300$$ $$K.$$ the thermal conductivity of copper is $$400$$ $$W/m.$$...

The value of Biot number is very small (less than $$0.1$$), when

The heat transfer process between a body and its ambient is governed by an internal conductive resistance $$\left( {{\rm I}CR} \right)$$ and an external convective resistance $$(EC...