A circular conducting loop of radius r carrying a current I is placed in a magnetic field `vecB` in such a way that the plan of the loop is perpendicular to `vecB`. What will be the magnitude of the magnetic forces exerted on the loop ?

Explanation

Let us consider an infinitensimal element `d vecl` at point P of the of the loop. The magnetic force on this element,
`dvecF=Idvecl xx vecB=IdB sin 90^(@)`
[ `:. dvecl` is perpendicular to `vecB`]
`=Idlb` (directed along `vec(OP)`)

similarly. if we consider opposite end of P, then the magnetic force on this element will be IdlB(directed along `vec(OQ)`). So the net force on two infinitesimal elements located on opposite ends of a diameter is zero. In this manner, if we divide the whole loop into such paris of inifinitesimal elements, the net force on each pair will be zeron. Hence that thenet force on the loop will be zero.