Twenty seven drops of same size are charged at 220 V each. They combine to form a bigger drop. Potential of bigger drop is:
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Twenty seven drops of same size are charged at 220 V each. They combine to form a bigger drop. Potential of bigger drop is:

G1 Physics · Accepted Answer

Step 1: Let each drop radius r, charge q, potential v = kq/r = 220 V. Step 2: Volume conservation gives bigger radius R = 27¹ᐟ³r = 3r. Step 3: Total charge Q = 27q. Step 4: Bigger potential V = k(27q)/(3r) = 9v = 1980 V.