THE VOLUME OF AIR BUBBLE IS DOUBLED WHEN IT RISES FROM BOTTOM OF LAKE TO ITS SURFACE. THE ATMOSPHERIC PRESSURE IS 75CM OF MERCURY AND RATIO OF DENSITY OF MERCURY TO THAT OF LAKE IS 40/3.

FIND THE DEPTH OF THE WATER.

Dear Akhil Killawala,

Ans:- 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

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