An air bubble doubles in radius on rising from the bottom of a lake to its surface. If the atmospheric pressure is equal to that of a column of water of height H, the depth of lake is

An air bubble doubles in radius on rising from the bottom of a lake to

1.	An air bubble doubles in radius on rising from the bottom of a lake to its surface. If the atmospheric pressure is equal to that of a column of water of height H, the depth of lake is
Answer» (a) H (b) 2H (c) 7H (d) 8H Solution :Since the RADIUS becomes double, the volume becomes eight times. Therefore, according to Boyle.s LAW, the PRESSURE at the SURFACE `Hrhog`. Therefore pressure at the bottom must be `8Hrhog`. Hence the depth of the LAKE is 7H.