Q. Two short magnets of magnetic moment $1000\ Am^{2}$ are placed as shown at the corners of a square of side $10\ cm$. The net magnetic induction at $P$ at
A) $0.1\ T$
B) $0.2\ T$
C) $0.3\ T$
D) $0.4\ T$
Explanation
(a) Point $P$ lies on equatorial lines of magnet (1) and axial line of magnet (2) as shown
$B_{1} = \frac{\mu_{0}}{4\pi}.\frac{M}{d^{3}} = 10^{- 7} \times \frac{1000}{(0.1)^{3}} = 0.1T$
$B_{2} = \frac{\mu_{0}}{4\pi}.\frac{2M}{d^{3}} = 10^{- 7} \times \frac{2 \times 1000}{(0.1)^{3}} = 0.2T$
$\therefore B_{net} = B_{2} - B_{1} = 0.1\ T$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.