Magnetism Question 157
Question: A magnet of magnetic moment M and pole strength m is divided in two equal parts, then magnetic moment of each part will be
[MP Board 1985; MP PET 1984, 2000; NCERT 1974; AFMC 1996; MP PMT 2002; MH CET (Med.) 2001; CPMT 1983, 84; KCET 1994, 2001]
Options:
A) $ M $
B) $ M/2 $
C) $ M/4 $
D) $ 2M $
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Answer:
Correct Answer: B
Solution:
If cut along the axis of magnet of length l, then new pole strength $ {m}’=\frac{m}{2} $ and new length $ {l}’=l $
$ \
Therefore $ New magnetic moment $ {M}’=\frac{m}{2}\times l=\frac{ml}{2}=\frac{M}{2} $ If cut perpendicular to the axis of magnet, then new pole strength $ {m}’=m $ and new length, $ {l}’=l/2 $
$ \
Therefore $ New magnetic moment $ {M}’=m\times \frac{l}{2}=\frac{ml}{2}=\frac{M}{2} $
BETA
