Magnetism Question 245
Question: A steel wire of length $ \ell $ has a magnetic moment M. It is bent in L-shape. The new magnetic moment is
Options:
A) M
B) $ \frac{M}{\sqrt{2}} $
C) $ \frac{M}{2} $
D) $ 2M $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Magnetic moment, $ M=m\ell $
$ \frac{M}{\ell }=m $ , where m is the polestrength.
Therefore distance between poles $ =\sqrt{{{(\ell /2)}^{2}}+{{(\ell /2)}^{2}}}=\frac{\ell }{2} $ So, $ M’=\frac{m\ell }{\sqrt{2}}=\frac{M}{\sqrt{2}} $
BETA
