Magnetism Question 213
Question: A bar magnet of length 3 cm has points A and B along its axis at distances of 24 cm and 48 cm on the opposite sides. Ratio of magnetic fields at these points will be
[DPMT 2004]
Options:
A) 8
B) $ 1/2\sqrt{2} $
C) 3
D) 4
Show Answer
Answer:
Correct Answer: A
Solution:
Both points A and B lying on the axis of the magnet and on axial position $ B\propto \frac{1}{d^{3}} $
Therefore $ \frac{B _{A}}{B _{B}}={{( \frac{d _{B}}{d _{A}} )}^{3}}={{( \frac{48}{24} )}^{3}}=\frac{8}{1} $
BETA
