Question

What is the relation of the provision of tubes with respect to dissipation of heat?

(a) the provision of tubes is directly proportional to the dissipation of heat

(b) the provision of tubes is indirectly proportional to the dissipation of heat

(c) the provision of tubes is directly proportional to square of the dissipation of heat

(d) the provision of tubes is indirectly proportional to square of the dissipation of heat

The question was posed to me in examination.

My question is taken from Design of Tank in portion Design of Transformers of Design of Electrical Machines

Answer 1

Correct answer is (b) the provision of tubes is indirectly proportional to the dissipation of heat

Best explanation: The provision of tubes increases the dissipating area. The increase in dissipation of heat is not proportional to area because tube screen some of the tank surface preventing radiation from there.