Direction of magnetic force on a positive charge moving in a magnetic field is given by

Explanation

When an electric charge q is moving with velocity `vec(v)` in the magnetic field `vec(B)`, it experiences a force, called magnetic force `vec(F_(m))`. After careful experiments. Lorentz deduced the force experienced by a moving charge in the magnetic field `vec(F_(m))`
`vec(F_(m)) = q (vec(v) xx vec(B)) " " `....(1)
In magnitude, `F_(m) = qvB sin theta" "` ....(2)
In magnitude ,(1) and (2) imply
1. `vec(F_(m))` is directly proportaional to the magnetic field `vec(B)`
2.`vec(F_(m))` is directly proportaional to the velocity `vec(v)`
3. `vec(F_(m))` is directly proportaional to sine of the angle between the velocity and magnetic field
4. `vec(F_(m))` is directly proportaional to the magnitude of the charge q
5. The direction of `vec(F_(m))` is always perpendicular to `vec(v)` and `vec(b)` as `vec(F_(m))` is the cross product of `vec(v) and vec(B)`
6. the direction of `vec(F_(m))` is on negative charge is opposite to the direction of `vec(F_(m))` on positive charge provided other factors are identical.
7. If velocity `vec(v) ` of the charge q ia along magnetic field `vec(B)` then, `vec(F_(m))` is zero.