What is the magnitude and direction of the electric force on a -3.0 µC charge at a point where the electric field is 2800 N/C and is directed along the +y axis.

Question

Quizplus · Accepted Answer

The electric force (F) on a charge (q) is calculated using the formula F=qE, where E is the electric field. 
In this case, the charge is -3.0 µC, which is negative, and the electric field is 2800 N/C along the +y axis, which means it is also in the -y direction for the negative charge. 
Thus, we have F = (-3.0 × 10^-6 C) × (2800 N/C) = -8.4 × 10^-3 N in the -y direction. 
Note that the magnitude of the force is always positive, so we take the absolute value before reporting the answer. 
Therefore, the magnitude of the electric force on the charge is 8.4 × 10^-3 N in the -y direction. The closest choice is (C) with 0.0084 N in the -y direction.

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