Question

A long straight wire carries a steady current I along the positive y-axis in a coordinate system. A particle of charge + Q is moving with a velocity vector v along the x-axis. In which direction will the particle experience a force?

Answer 1

From relation vector F=qvB[i cap (–k cap)] = +qvB(j cap)
Magnetic force vector F along + y axis.

or

From Fleming’* left hand rule, thumb points along + y direction, so the direction of magnetic force will be along + y axis (or in the direction of flow of current).