Answer:
Option B
Explanation:
(A) Convection involved flow of matter within a fluid due to heat transferred from one point to another by the actual motion of matter from a region of high-temperature to a region of lower temperature
(B) A hot bar placed under a running top water loses heat with in water.The warmer water rises up , these leads to circulation of heat from bar to water by the process of convection.
However, heat will be transferred inside the molecules of the bar also by conduction. Thus, the heat transfer when a hot bar placed under a running top water is due to both conduction and convection.
(C) Heat can only be transferred between two system due to their temperature difference in the form of radiation, molecular vibrations, molecular displacement etc.
