Question

When heating a pot of pasta on an electric stove as shown, which heat transfer mechanisms are taking place?

A: Only conduction from the electric heat element to the metal pan

B: Only convection through the water in the pan

C: Only radiation outward from the glowing heat element

D: All three mechanisms are taking place

Answer 1

Conduction :

Heat transfer from one end of rod to other end when placed on stove can occur. This transfer takes place due to molecular collisions and the process is called heat conduction.

Convection :

When heat transfer takes place from one place to another due to actual motion of heated material convection occurs.

Radiation does not need any material medium for heat transfer.

When electric energy is emitted by a electric stove this energy travels in space just like light.

Here pasta pan is in immediate contact with electric stove.so when radiation falls on pasta pan a part of it is absorbed and thermal energy of pan increases.

From Lower part of pan to upper part thermal energy or heat is now transferred by conduction.

When water at the bottom in pasta pot gets this heat due to conduction through pot's bottom. Thus water density decreases and consequently it rises.Thus heat is carried from bottom to top by actual movement of the parts of water.Thus convection occurs.

Thus, answer of the question is

D) All three mechanisms are taking place.