A bubble of the gas released at the bottom of a lake increases to eight times the original volume when it reaches at the surface. Assuming that the atmospheric pressure is equivalent to pressure exerted by a column of water 10 m high, what is the depth of the lake

Options

A. 80 m
B. 90 m
C. 10 m
D. 70 m

Answer

D

Explanation

(d) let V be the original volume of bubble. The final volume will be 8 V. let P be the atmospheric presure and `P_(1)` the pressure at the bottom
`therefore Pxx8V=P_(1)xxV`
`8p=P_(1)`
`P_(1)`=atmospheric pressure+pressure due to water lake
=P+7p
the P=10m high, the 7p will be=70m high
so the depth=70 m