A-LevelPhysicsElectric fieldsOct/Nov 2010Paper 1 Q291 Mark
A very small oil drop of mass m carries a charge +q. [Figure showing a charged oil drop suspended between two parallel plates. The top plate is negative, bottom plate is positive. Electric field points downwards.] The potential difference across the plates is V and the separation is d. The weight of the drop is balanced by the electric force. (Buoyancy forces may be considered to be negligible.) Which formula gives the charge on the drop?
Aq = mgd / V
Bq = mgV / d
Cq = Vd / mg
Dq = V / (mgd)
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The correct answer is A. This question tests the candidate's understanding of electric fields within the Physicssyllabus. The examiner's mark scheme requires...
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