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JEE Previous Year Question

$27 identical drops are charged at 22V each. They combine to form a bigger drop. The potential of the bigger drop will be____V.$

Topic: JEE PYQ

Answer: 198. Full step-by-step solution below.

Correct answer: 198

Solution

(198) q \to n q n \frac{4}{3} π r^{3} = \frac{4}{3} π (r ’)^{3} \Rightarrow r ’ = n^{\frac{1}{3}} r V = \frac{kq}{r} \propto \frac{n}{n ^{1/3}} \propto n^{2/3} \propto 2 7^{2/3} \Rightarrow v ’ = 9 V = 9 \times 22 = 198

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