Question

Water of depth 10 m exerts a pressure equal to atmospheric pressure. An air bubble rises to
the surface of a lake which is 20 m deep. When the bubble reaches the surface, its volume is
6 cm'.
What was the volume of the air bubble at the bottom of the lake?
(N2004 P1 Q15)
A 2 cm
B 3 cm' C 12 cm' D 18 cm. ( )​

Answer 1

Answer:As volume of air bubble becomes double on reaching the surface of lake, hence its pressure becomes half. Since on the lake, the pressure is equal to the atmospheric pressure, hence the pressure of air inside the bubble at the depth of lake = 2 atmospheric pressure = atmospheric pressure + pressure due to column of water h. thus

2×76 cm of Hg=76 cm of Hg+ h cm of water or 76 cm of Hg = h cm of water of Depth of lake= 76 cm of Hg=76 xx 13.6 cm of water=1033.6 cm = 10.34 m

Explanation: