Q 12-05-010NEETJEE MainEasy
A bar magnet of length $10$ cm and pole strength $2$ A m is cut into two equal halves perpendicular to its length. The magnetic moment of each half is
Answer: (A) $0.1\ \text{A m}^2$
Concept. Cutting perpendicular to the length keeps the pole strength and halves the length; $M = m \times$ length.
Step 1. Length of each half. $\dfrac{10}{2} = 5$ cm $= 0.05$ m.
Step 2. Moment. $M = 2 \times 0.05 = 0.1\ \text{A m}^2$ (half of the original $0.2\ \text{A m}^2$).
Answer. $0.1\ \text{A m}^2$ (Option A).
Solution by Sreeraj P, M.Sc Physics