Answer: Electric force = gravity.
- A No forces act on it
- B Electric force = gravity
- C Electric force > gravity
- D Gravity = zero
Correct answer: B. Electric force = gravity
Explanation: Drop is stationary when electric force qE exactly balances gravitational force mg: qE = mg.
Field lines (radial) and equipotential lines (concentric circles) of a point charge. Equipotential surfaces are always perpendicular to the field lines. Image: Sjlegg, Public Domain, via Wikimedia Commons.
Concept context
Electric potential, equipotential surfaces, potential energy of charge systems, conductors, dielectrics, capacitors, combinations, and energy storage.
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