27 identical drops of mercury are charged simultaneously to the same potential of 10 volt. Assuming the drops to be spherical, if all the charged drops are made to combine to form one large drop, then its potential will be volt.

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(2) 90. Given: n = 27 drops, each of radius r and charge q, at potential V = (Kq)/r = 10 V. Idea: both charge and volume are conserved when the drops merge. Charge: Q = nq = 27q. Volume: 4/3π R³ = 27×4/3π r³, so R = 3r. V' = (KQ)/R = (27Kq)/(3r) = 9×10 = 90 V (in general V' = n^2/3V). So the large drop is at 90 V.

27 identical drops of mercury are charged simultaneously to the same potential of 10 volt. Assuming the drops to be spherical, if all the charged drops are made to combine to form one large drop, then its potential will be _____ volt.

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