The magnetic induction in air at a distance d from an isolated point pole of strength m unit will be [MNR 1987; CPMT 1991; MP PET 1995; AMU 1999; J & K CET 2005]

• A.            \[\frac{m}{d}\]                    
• B.            \[\frac{m}{{{d}^{2}}}\]
• C.            \[md\]                                    
• D.            \[m{{d}^{2}}\]