Question

A collapsible balloon is inflated to a volume of 10 L at a pressure of 1 atm. When the balloon is immersed to the bottom of a lake, its volume reduces to 1.25 L. Assuming 1 atm pressure to be equivalent to 10 m column of water and no change in temperature, the depth of the lake will be

• A. 70 m
• B. 80 m
• C. 90 m
• D. None of these

Answer 1

The correct option is A

70 m

Pressure at the surface of lake, $P_1=1atm\cong 10m$
column; $V_1=10L$
Pressure at the bottom, $P_2\equiv (10+x)m$ column,
$V_2=1.25L$
Applying $P_1{V}_1=P_2{V}_2,$ x = depth = 70 m