Anyone please tell what is lower box and upper region in the given figure. Anyone please explain this. Don't post irrelevant answers. Anyone please explain me what is this.
Answers
To explain this, first you need to know about what is Conduction, Convection and Radiation.
Conduction: The transfer of thermal energy through direct contact.
Convection: The transfer of thermal energy through a liquid or gas.
Radiation: The transfer of thermal energy through thermal emission.
1. Here the lower surface and upper surface is of the same pan, means it is the same object so the heat is transferred direct contact, since same object.
2. Here, don't get confused of the word 'lower box' it means the lower surface water to the upper surface water i.e. convection. (Convection: Transfer of thermal energy through liquid or gas and water is a liquid.)
3. Here, at last, the heat is transferred from the flame to the bottom of the pan i.e. Radiation. And here the transfer is through thermal emissions of the flame.
Thank you!