question_answer

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

A) H                                 

B) 2 H

C) 7 H

D) 8 H

Correct Answer: C

Solution :

We get, If r is 2 times, V becomes 8 times at the surface of lake. Pressure at the surface of lake is given where, Pressure at the bottom of lake,  where, h = depth of lake Let final volume, . Because temperature is constant, hence from Boyle?s law