question_answer

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

Correct Answer: C

Solution :

Pole strength of each part = m Magnetic moment of each part \[=\,\,M = mL\,\,=\,\,mL\,\,=\,\,\frac{M}{2}\]