Two parallel horizontal plates are spaced 0.40 cm apart in air. You introduce an oil droplet of mass 4.9 × 10^-17 kg between the plates. If the droplet carries two electronic charges and if there were no air buoyancy, you could hold the droplet motionless between the plates if you kept the potential difference between them at

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Quizplus · Accepted Answer

The electric force must balance the gravitational force. Using F = qE and E = V/d, where q is the charge (2e), V is the potential difference, and d is the distance between plates, we find V = mgd/q. Substituting the given values, V = 6.0 V.

Two Parallel Horizontal Plates Are Spaced 0