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How did you determine that the direction is south?

Hi Physics 120, thanks for the question. You're asking how we know the electric field is directed South, I assume. A bit of background first:

Electric field points in the direction in which it would push a positive charge.

Note the emphasis on positive. Since this question concerns an electron, the charge is negative. That doesn't change the convention about electric field direction: it still points in the direction of force that would be applied on a positive charge. You could also say the electric field always points in the opposite direction to the force it applies on a negative charge. In this question we have a negative charge experiencing a force North, and so the electric field is pointing in the opposite direction: South.

Hope that helps, and good luck with "Physics 120"!
Mr. Dychko