When air bubble comes from bottom to the top of a lake its radius becomes n times. If temprerature remains constant through out the lake the depth of the lake will be.

Explanation

From Boyle.s law PV= constant `rArr P_(1)V_(1)=P_(2)V_(2)`
`(P_(0)+hrho+(2T)/(R))(4)/(3)piR^(3)=(P_(0)+(2T)/(nR))(4)/(3)pi(nR)^(3)`
`hrhog=P_(0)(n^(3)-1)++(2T)/(nR)n^(3)-(2T)/(R )`
`h=(P_(0)(n^(2)-1)+(2T)/(R )[n^(2)-1])/(rhog)`