Magnetism Question 34
Question: Two magnets of equal mass are joined at right angles to each other as shown the magnet 1 has a magnetic moment 3 times that of magnet 2. This arrangement is pivoted so that it is free to rotate in the horizontal plane. In equilibrium what angle will the magnet 1 subtend with the magnetic meridian
Options:
A) $ {{\tan }^{-1}}( \frac{1}{2} ) $
B) $ {{\tan }^{-1}}( \frac{1}{3} ) $
C) $ {{\tan }^{-1}}(1) $
D) 0°
Show Answer
Answer:
Correct Answer: B
Solution:
For equilibrium of the system torques on M1 and M2 due to BH must counter balance each other i.e. $ M _{1}\times B _{H}=M _{2}\times B _{H} $ . If q is the angle between M1 and BH will be $ (90-\theta ) $ ; so $ M _{1}B _{H}\sin \theta =M _{2}B _{H}\sin (90-\theta ) $
$ \Rightarrow \tan \theta =\frac{M _{2}}{M _{1}}=\frac{M}{3M}=\frac{1}{3}\Rightarrow \theta ={{\tan }^{-1}}( \frac{1}{3} ) $
BETA
