Bar Magnet & Magnetic Moment question from NEET 2024

Answer: (b)

1. Pole strength $m = M/L$ is unchanged.
2. Each arm is $L/2$ with $60^\circ$ between them, so the triangle formed is equilateral: end-to-end distance $= L/2$.
3. $M' = \dfrac{M}{L}\cdot\dfrac{L}{2} = \dfrac{M}{2}$
4. So the answer is (b) $\frac{M}{2}$.