Question

A long magnetic needle of length 2L, magnetic moment M and pole strength m units is broken into two pieces at the middle. The magnetic moment and pole strength of each piece will be

• A. $\frac{M}{2},\frac{m}{2}$
  
• B. $M,\frac{m}{2}$
  
• C. $\frac{M}{2},m$
  
• D. $M,m$

Answer 1

The correct option is C $\frac{M}{2},m$

Pole strength of each part =m
Magnetic moment of each part
$=M^{\prime }=m^{\prime }{L}^{\prime }=mL=\frac{M}{2}$