Question

The magnetic potential at a point on the axial line of a bar magnet of dipole moment M is V. What is the magnetic potential due to a bar magnet of dipole moment $\frac{M}{4}$ at the same point?

• A. 4V
• B. 2V
• C. $\frac{V}{2}$
• D. $\frac{V}{4}$

Answer 1

The correct option is D $\frac{V}{4}$

Case-$I$

Potential $V$ at point $P$ along axis of magnet is

$V=\frac{{\mu }_0}{4\pi }\frac{M}{r^2}⟶\left(1\right)$

Case-$II$

Similarly, potential

$V_2=\frac{{\mu }_0}{4\pi }\frac{\frac{M}{4}}{r^2}⟶\left(2\right)$

From equation $\left(1\right)$ and $\left(2\right)$

$V_2=\frac{V}{4}$