Twenty seven drops of same size are charged at $220\, \mathrm{~V}$ each. They combine to form a bigger drop. Calculate the potential of the bigger drop. (In $\mathrm{~V}$)
A$1980$
B$1320$
C$1520$
D$660$
NEET 2021, Medium
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A$1980$
a ${V}_{\mathrm{B}}=\mathrm{N}^{2 / 3}\, \mathrm{~V}_{\mathrm{S}}$
$\mathrm{V}_{\mathrm{B}}=(27)^{2 / 3} \times 220$
$\mathrm{~V}_{\mathrm{B}}=9 \times 220$
$=1980\, \mathrm{~V}$
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