What is the direction of the electric field at a point directly below a negative charge, Q?

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Explanation:

The electric field produced by a single point charge (either positive or negative) is radial. The direction of the field lines is determined by the direction in which a small positive test charge immersed in the field will move. Therefore the field lines point towards the charge for a negative charge (because the small positive test charge is attracted by that)

The field lines point away from the charge for a positive charge (because the small positive test charge is repelled by that)

In this case, we have a negative charge Q: since the field lines are towards the charge, if we are at a point directly below the charge, the direction of the field is toward the charge, so upward.

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