Question

When a large bubble rises from the bottom of a lake to the surface, its radius doubles. If atmospheric pressure is equal to that of column of water height H, then the depth of lake is

• A. H
• B. 2H
• C. 7H
• D. 8H

Answer 1

Answer: (C)

7H

Answer 2

$P _ { 1 } V _ { 1 } = P _ { 2 } V _ { 2 }$⇒$= H \times \frac { 4 } { 3 } \pi ( 2 r ) ^ { 3 }$

$h = 7 H$