A north magnetic pole is facing another north magnetic pole with a distance xx. If the distance between the poles becomes 12x12x, what happens to the magnitude of the field energy between them

Explanation:

When two north magnetic poles are  placed close to each other , they will repel each other . If distance between them is increased due to mutual repulsion from x to 12 x , work is done by the magnetic field . This results in decrease of magnetic field energy .

Hence , when the distance between the poles becomes 12x from x , the magnitude of the field energy between them decreases .