Question

The magnetic field to a small magnetic dipole of magnetic moment M, at distance r from the centre on the equatorial line is given by (in M.K.S. system)

• A. $\frac { \mu _ { 0 } } { 4 \pi } \times \frac { M } { r ^ { 2 } }$
• B. $\frac { \mu _ { 0 } } { 4 \pi } \times \frac { M } { r ^ { 3 } }$
• C. $\frac { \mu _ { 0 } } { 4 \pi } \times \frac { 2 M } { r ^ { 2 } }$
• D. $\frac { \mu _ { 0 } } { 4 \pi } \times \frac { 2 M } { r ^ { 3 } }$

Answer 1

Answer: (B)

$\frac { \mu _ { 0 } } { 4 \pi } \times \frac { M } { r ^ { 3 } }$

Answer 2

$B _ { \text {equatorial } } = \frac { \mu _ { 0 } } { 4 \pi } \frac { M } { r ^ { 3 } }$