Magnetism Question 269
Question: A magnet makes 40 oscillations per minute at a place having magnetic field intensity of $ 0.1\times {{10}^{-5}},T $ . At another place, it takes 2.5 sec to complete one vibration. The value of earth’s horizontal field at that place is
Options:
A) $ 0.25\times {{10}^{-6}},T $
B) $ 0.36\times {{10}^{-6}},T $
C) $ 0.66\times {{10}^{-8}},T $
D) $ 1.2\times {{10}^{-6}},T $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] $ T _{1}=\frac{60}{40}=1.5s $ and $ T _{2}=2.5,s $ We know that, $ \frac{T _{1}}{T _{2}}=\sqrt{\frac{B _{2}}{B _{1}}} $ or $ B _{2}=\frac{T _{1}^{2}}{T _{2}^{2}}\times B _{1}={{( \frac{1.5}{2.5} )}^{2}}\times (0.1\times {{10}^{-5}}) $
$ =0.36\times {{10}^{-6}},T $
BETA
