CUET · PHYSICS · PYQ PAPER 2025
216 charged droplets, each of radius r and charge q, are combined to form a big drop. The ratio of potential of the big drop to the small droplet will be :
- A 216 :1
- B 49 : 1
- C 36 : 1
- D 7 : 1
Answer & Solution
Correct Answer
(C) 36 : 1
Step-by-step Solution
Detailed explanation
\(R = N^{1/3}r = (216)^{1/3}r = 6r\) \(Q = Nq = 216q\) \(\frac{V_b}{V_s} = \frac{kQ/R}{kq/r} = \frac{Q}{R} \cdot \frac{r}{q}\) \(\frac{V_b}{V_s} = \frac{Nq}{N^{1/3}r} \cdot \frac{r}{q} = N^{2/3}\) \(\frac{V_b}{V_s} = (216)^{2/3} = 6^2 = 36\) Ratio = \(36:1\)
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