Two short magnets of equal dipole moments M are fastened perpendicularly at their centres figure. The magnitude of the magnetic field at a distance d from the centre on the bisector of the right angle is


We know that the resultant magnetic field on a point P due to a dipole can be expressed as,



Where, M is the magnetic moment, r is the perpendicular distance of the point P from the centre of the dipole. Θ is the angle made by the line connecting the centre and the point P with that of axis of the dipole.


In the given question, as the point is on the angular bisector of the right angle, Θ is 45° . Hence the above expression becomes,



Or,



Here the point P will affected by both the crossed dipoles, hence the total magnetic field will be,



Or,



Or,



Thus, option C is the correct option.

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