A current carrying coil is subjected to a uniform magnetic feild The coil will orient so that its plane - Physics - Moving Charges And Magnetism

Question

A current carrying coil is subjected to a uniform magnetic feild
The coil will orient so that its plane becomes(a) inclined at 45
degree to the magnetic field
(b) inclined at any arbitrary angle to the magnetic field
(c) parallel to the maganetic field
(d) perpendicular to the magnetic fieldWhy the answe is (d) and
not (c) ?

Abhay Kumar · Accepted Answer

Lets first talk about the concept behind the question:we know that:magnetic torque on current carrying loop is given as :ζ=(NiA)xBwhere iNA is the magnetic moment which is perpendicular to the plane of wire,i is the current N the number of turns B is the magnetic field
So, the torque equation has to be zero, it is only possible when : NiA is in the direction of Bor plane is perpendicular to the magnetic field 
So the answer is D
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