Magnetism Question 87
Question: A magnetic needle is made to vibrate in uniform field H, then its time period is T. If it vibrates in the field of intensity 4H, its time period will be
[MP Board 1988; MP PMT 1992; MH CET (Med.) 1999]
Options:
A) $ 2T $
B) $ T/2 $
C) $ 2/T $
D) $ T $
Show Answer
Answer:
Correct Answer: B
Solution:
$ T=2\pi \sqrt{\frac{I}{MB_H}}\Rightarrow \frac{T_1}{T_2}=\sqrt{\frac{(B_H)_2}{(B_H)_1}} $
$ \Rightarrow T _{2}=T\sqrt{\frac{(BH)_1}{(BH)_2}}=\frac{T}{2}\ \ \ ( \because (B_H)_2=4(B_H)_1) $
BETA
