Magnetism Question 242
Question: A magnetic dipole is acted upon by two magnetic Fields which are inclined to each other at an angle of $ 75^{o} $ . One of the fields has a magnitude of 15 mT. The dipole attains stable equilibrium at an angle of $ 30^{o} $ with this field. The magnitude of the other field (in mT) is close to:
Options:
A) 1
B) 11
C) 36
D) 1060
Show Answer
Answer:
Correct Answer: B
Solution:
[b] We know that, magnetic dipole moment $ M=NiA,\cos ,\theta $ i.e., $ M\propto ,\cos ,\theta $ When two magnetic fields are inclined at an angle of $ 75{}^\circ $ the equilibrium will be at $ 39{}^\circ $ , so $ \cos \theta =\cos ,(75{}^\circ -30{}^\circ )=,\cos ,45{}^\circ =\frac{1}{\sqrt{2}} $
$ \frac{x}{\sqrt{2}}=\frac{15}{2},,\
Therefore ,,,x\approx 11 $
BETA
