Question

The volume of an air bubble becomes three times as it rises from the bottom of a lake to its surface. Assuming atmospheric pressure to be 75 cm of Hg and the density of water to be 1/10 of the density of mercury, the depth of the lake is

• A. 5 m
• B. 10 m
• C. 15 m
• D. 20 m

Answer 1

Answer: (C)

15 m

Answer 2

$\left( P _ { 0 } + h \rho g \right) V$=

⇒ $h \rho g = 2 P _ { 0 }$⇒ $h = \frac { 2 \times 75 \times 13.6 \times g } { \frac { 13.6 } { 10 } \times g }$= 15 m