Magnetism Question 94
Question: At two places A and B using vibration magnetometer, a magnet vibrates in a horizontal plane and its respective periodic time are 2 sec and 3 sec and at these places the earth’s horizontal components are HA and HB respectively. Then the ratio between HA and HB will be
[MP PMT 1985, 89]
Options:
A) 9 : 4
B) 3 : 2
C) 4 : 9
D) 2 : 3
Show Answer
Answer:
Correct Answer: A
Solution:
$ T=2\pi \sqrt{\frac{I}{MH}}\Rightarrow T\propto \frac{1}{\sqrt{H}} $
Therefore $ \frac{T _{A}}{T _{B}}=\sqrt{\frac{H _{B}}{H _{A}}} $
Therefore $ \frac{H _{A}}{H _{B}}= $
$ {{( \frac{T _{B}}{T _{A}} )}^{2}}={{( \frac{3}{2} )}^{2}}=\frac{9}{4} $ .
BETA
