the volume of an air bubble is doubled as it Rises from the bottom of Lake to its surface the atmospheric pressure is 75 cm of Mercury the ratio of density of Mercury to that of Lake water is 40 by 3 the death of the lack in metre isu

The pressure at the bottom of the lake is = The pressure due to hte air + The pressure due to the water column=P1

The pressure at the top is only the atmosphereic pressure=P2 Initial Vol=V1 and final Vol is =V2

NOW YOU HAVEN'T MENTIONED ABOUT THE TEMP SO I AM CONSIDERING IT TO BE CONSTANT

So from gas eq we get P1V1 = P2V2

V2=2V1

Putting the values in the eq 1 we get,

H=10 meter