An electron moving north encounters a uniform magnetic field if the magnetic field points east what is the direction of the magnetic force on the electron

force is leaving the sheet of paper

Explanation:

The magnetic force is given by the expression

       F = q v x B

where the boldface indicates vectors, this expression can be separated in its module

       F = q v B sin θ

dodne θ at the angle between velocity (v) and the magnetic field (B)

the direction can be found by the right-hand rule, where for a positive charge the thumb points in the direction of speed, the other fingers extended in the direction of the magnetic field and the palm in the direction of force, if the charge is negative the direction of the force contrary to the direction of the palm.

Then

the thumb is in the North direction

fingers extended in the east direction

The palm points entering the sheet, but since the charge is negative the force is leaving the sheet of paper

neither accurate nor precise.