00:01
Hello student, here the magnetic force on the wire is i l cross b where l is the length of the wire and it is along the direction of current and b is the magnetic field.
00:19
So here the wire current flows through the wire along east direction and the wire slides along north.
00:35
So now we can consider this axis as y axis, this is as z axis.
00:41
So the magnetic field will be perpendicular to both the force and the current.
00:50
So magnetic field will be along x axis.
00:55
So here l is along this direction, this is the direction of b and this is the direction of force.
01:03
Now so we can write i l b, if magnetic force f m equals to i l into b.
01:15
For minimum magnetic field or b minimum, magnetic force is just equal to the frictional force.
01:30
So f m equals to f s.
01:36
Now f s equals to frictional force, f s equals to mu m into g where m is the mass of the wire...