When a large bubble rises from the bottom

Question

When a large bubble rises from bottom of a lake to the surface. Its radius doubles . If atmospheric  pressure  is equal to the column of water height H, then depth of lake is

A) H

B)2H

C ) 7H

D)8H

Answer 1

Correct option (C ) 7H

Explanation:

According to Boyle 's law,

Answer 2

OPTION (C)

Explanation

Given atmospheric pressure = H (height of water column)

Let the radius of the bubble at the bottom be r, then its volume = 4/3πr^3

When it comes to the surface its radius becomes 2r,

So volume of the bubble at the surface = 4/3(2r)^3

So V/v =8

Now by Boyle's law

v×(h+H)=V×H, where h is the depth of the Lake

=> h+H =(V/v)×H

=> h + H = 8H

=> h = 7H