Force on charges reverses sign in electric fields Steps:

• Identify the field type: "Charged particle" suggests electric field, as gravity involves mass, not charge.
• Recall electric field definition: Direction of E is the force direction on a positive test charge (F = qE).
• For negative charge (q < 0), force F points opposite to E.
• Rule out gravity: Gravitational field g points in force direction (F = mg, m > 0 always), so force never opposes g.

Why B is correct:

• F = qE; negative q makes F antiparallel to E, matching the opposite direction described.

Why the others are wrong:

• A: Positive q makes F parallel to E, not opposite.
• C: No negative "charge" in gravity; mass always positive, force aligns with g.
• D: Gravity has no positive/negative charges; force always follows field direction.

Final answer: B