Question

The ratio of magnetic induction due to a bar magnet on its axial point and equatorial point will be :

• A. $1:1$
• B. $1:2$
• C. $2:1$
• D. $1:4$

Answer 1

The correct option is C $2:1$

Magnetic induction at axial point = $\overrightarrow{B}$ axial = $\frac{\mu o}{4\pi }\frac{2\overrightarrow{m}}{r^3}$

Magnetic induction at equatorial point = $\overrightarrow{B}$ equ. = $\frac{\mu o}{4\pi }\frac{\overrightarrow{m}}{r^3}$

$\mu$ = $4\pi \times {10}^{-7}$ $Tm{A}^{-1}$

$\overrightarrow{m}$ = magnetic moment.

r = distance of point from mid point of magnet.

$\frac{\overrightarrow{B}axial}{\overrightarrow{B}eua.}=\frac{\mu o}{4\pi }\times \frac{2\overrightarrow{m}}{\mu o}\times \frac{r^3}{\overrightarrow{m}}=2$.

OPTION : C.