Question

Among the following statements.
A) A bar magnet of moment $M$ is bent into a semicircle, then its magnetic moment decreases.
B) The resultant magnetic induction field at a point on the equatorial line is antiparallel to magentic moment of the bar magnet.

• A. $A$ is true & $B$ is false
• B. $A$ is false & $B$ is true
• C. $A$ and $B$ are true
• D. $A$ and $B$ are false

Answer 1

The correct option is C $A$ and $B$ are true

Statement (A)
Let $M$ be magnetic moment of bar magnet
Magnnetic moment when bar magnet is bent into semicircle is $M^{\prime }=\frac{2M\sin \left(180/2\right)}{\pi }=\frac{2m}{\pi }$
$M^{\prime }<M$

Statement (B) ${\overrightarrow{B}}_{eq}$ and $\overrightarrow{M}$ are antiparallel.

Hence, both $A\&B$ are true