In an electric field, the force on a positive test charge is in the same direction as the field. Which statement is correct?

• A. True; the force is in the same direction as the field.
• B. False; the force is opposite to the field.
• C. The force is perpendicular to the field.
• D. The force is unrelated to the field direction.

Answer: (A)

In an electric field, the force on a positive test charge points in the same direction as the field because the force on a charge q is F = qE. When q is positive, F has the same direction as E, which is exactly what the statement says. The electric field is defined as the direction a positive test charge would be pushed, so for a positive charge the force and the field align. If the charge were negative, the force would point opposite to the field, which is why the other ideas don’t fit. The force isn’t generally perpendicular to the field in this basic electrostatic situation, and it’s not unrelated to the field’s direction.