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Two short bar magnets A and B of dipole moments 0.15 A m^(2) and 1.2 A m^(2) respectively are placed with their axes along the same line with their centres 0.15 m apart. The dipole moments due to A and B point in opposite directions. What is the position of the point, between the two magnets, where the resultant induction is zero? |
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Answer» 10 cm from the centre of A `:. B_(1) = B_(2)` (in magnitude) ` therefore mu_(0)/(4pi)(2m_(1))/d_(1)^(3)=mu_(0)/(4pi)(2m_(2))/((0.15-d_(1))^(3))` `IMPLIES (0.15)/d_(1)^(3)=(1.2)/((0.15-d_(1))^(3))implies1/d_(1)^(3)=8/((0.15-d_(1))^(3))` `implies 8d_(1)^(3) = (0.15 - d_(1))^(3)` Taking cube ROOTS of both sides, we get `2d_(1) = 0.15 - d_(1)or 3d_(1) = 0.15` `implies d_(1) = 0.05 m = 5cm` `therefore` P is at a distance of 5 cm from the centre of A. 
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