Moving Charges And Magnetism

Proton will represent the direction of current.
So, the direction of current is vertically downward.
According to Fleming's left hand rule, if middle finger represents the direction of current and fore-finger represents the direction of magnetic field, then thumb will represent the direction of Lorentz force acting on the proton which deflects the proton in east direction.
Alternative
Force on proton in magnetic field.

Here,


Hence, force will act on the proton in -direction, ie, towards east.

Here, Magnesium is a paramagnetic substance and it follows, i.e constant In first case, In second case,