Question

A conductor (shown in the figure) carrying constant current `I` is kept in the `x-y` plane in a uniform magnetic field ` vec(B)`. If ` vec(F)` is the magnitude of the total magnetic force acting on the conductor, then the correct statement(s) is (are)

A. If `vecB` is along `hatz, Fprop (L+R)`
B. If `vecB` is along `hatx, F=0`
C. If `vecB` is along `haty, Fprop (L+R)`
D. If `vecB` is along `hatz, F=0`

Answer 1

Correct Answer - (a,b,c)
As `vecB` is uniform
`implies` Wire can be replaced by a straight current carrying conductor.
`implies vecF=i(veclxxvecB)`
`=(2(L+R)hatixxvecB)`
if `vecB` is along x-axis `implies vecF=0`
otherwise `Fprop(L+R)`