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JEE Main 2023 (12 Apr, Shift 1) · Electric Potential & Equipotentials

Electric Potential & Equipotentials question from JEE Main 2023 (12 Apr, Shift 1)

Q60JEE Main 2023 · 12 APR · SHIFT 1Easy

Electric Potential & Equipotentials

64 identical drops each charged upto potential of 10 mV10\text{ mV} are combined to form a bigger drop. The potential of the bigger drop will be __________ mV\text{mV}.

Numerical answer type. Work it out, then open the answer.

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Answer: 160

  1. Charge is conserved: Q=nqQ = nq; volume is conserved: 43πR3=n⋅43πr3⇒R=n1/3r\frac{4}{3}\pi R^3 = n\cdot\frac{4}{3}\pi r^3 \Rightarrow R = n^{1/3}r
  2. V′=kQR=knqn1/3r=n2/3VV' = \frac{kQ}{R} = \frac{knq}{n^{1/3}r} = n^{2/3}V
  3. V′=642/3×10=16×10=160 mVV' = 64^{2/3}\times 10 = 16 \times 10 = 160\text{ mV}
  4. So the answer is 160 mV.
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