Question

When we magnetize the ferromagnetic core of the transformer, core length_______ and it ______ when demagnetized.

(a) decreases, increases

(b) decreases, decreases

(c) increases,increases

(d) none of the mentioned

This question was addressed to me in examination.

My enquiry is from Three Phase Transformers topic in chapter Transformers of Electrical Machines

Answer 1

Correct option is (a) decreases, increases

To explain I would say: Due to aligned magnetic dipoles in the material, the size will reduce by a small margin and vice versa while demagnetization.