Notifications
Clear all
0
15/09/2021 1:06 pm
Topic starter
Twenty-seven drops of same size are charged at 220 V each. They combine to form a bigger drop. Calculate the potential of the bigger drop.
(1) 660 V
(2) 1320 V
(3) 1520 V
(4) 1980 V
1 Answer
0
15/09/2021 1:11 pm
Correct answer: (4) 1980 V
Explanation:
\(\frac{4}{3}\pi R^3\) = 27\((\frac{4}{3}\pi r^3)\) ⇒ R = 3r .....(1)
V = \(\frac{Kq}{r}\) ⇒ \(\frac{V_1}{V_2}\) = \((\frac{q_1}{q_2})\)\((\frac{r_2}{r_1})\)
⇒ \(\frac{220}{V_2}\) = \((\frac{q}{27q})\)\((\frac{3r}{r})\)
⇒ \(\frac{220}{V_2}\) = \(\frac{1}{9}\)
⇒ V2 = 220 x 9 = 1980 volt