In order to heat air it is important to to increase the area of contact between the air and the surface gathering the heat
Answers
According to the statement mentioned in the question that,
In order to heat air it is important to to increase the area of contact between the air and the surface gathering the heat.
This statement is not true.
Because the heat is transported into the air molecules,by the process of radiation and convection.
And both of these processes do not depend on the surface area for the heat gathering.
That's why the statement mentioned in question is completely false.
The statement, “In order to heat air it is important to increase the area of contact between the air and the surface gathering the heat” is false because the heat is transferred to the molecules of air not by conduction, but convection and radiation.
Unlike conduction, which means transfer of heat by direct contact, these two processes do not depend on the surface area for transference of heat.