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12.Kinetic Theory of Gases
medium
An air bubble doubles its radius on raising from the bottom of water reservoir to be the surface of water in it. If the atmospheric pressure is equal to $10\, m$ of water, the height of water in the reservoir is ..... $m$
A
$10$
B
$20$
C
$70$
D
$80$
Solution
(c) According to Boyle’s law ${({P_1}{V_1})_{{\rm{bottom}}}} = {({P_2}{V_2})_{{\rm{top}}}}$
$(10 + h) \times \frac{4}{3}\pi r_1^3 = 10 \times \frac{4}{3}\pi r_2^3$ but ${r_2} = 2{r_1}$
$\therefore$ $(10 + h)r_1^3 = 10 \times 8r_1^3$==> $10 + h = 80$ $\therefore h = 70m$
Standard 11
Physics
