Magnetism Question 209
Question: A bar magnet when placed at an angle of 30o to the direction of magnetic field induction of 5 ´ 10?2 T, experiences a moment of couple 25 ´ 10?6 N-m. If the length of the magnet is 5 cm its pole strength is
[EAMCET (Med.) 2000]
Options:
A) 2 ´ 10?2 A-m
B) 5 ´ 10?2 A-m
C) 2 A-m
D) 5 A-m
Show Answer
Answer:
Correct Answer: A
Solution:
$ \tau =MB\sin \theta \Rightarrow \tau =(mL)B\sin \theta $
$ \Rightarrow 25\times {{10}^{-6}}=(m\times 5\times {{10}^{-2}})\times 5\times {{10}^{-2}}\times \sin 30 $
$ \Rightarrow m=2\times {{10}^{-2}}A-m $ .
BETA
