How Do You Calculate Absolute Pressure at a Depth Using Bubble Size Changes?

[J0hnnyD]

Problem:

An air bubble originating froman under water
diver has a radius of 5 mm at some depth h.
When the bubble reaches the surface of the
water, it has a radius of 7.4 mm.
Assuming the temperature of the air in the
bubble remains constant, determine the abso-
lute pressure at this depth h. The acceleration
of gravity is 9.8 m/s2 .
Answer in units of Pa.

Homework Equations

what I need to know. Is this a PV=nRT question??

The Attempt at a Solution

I don't need to know the answer to the question, just what equation to use to find the absolute pressure. there is a follow up question to determine the depth of the diver as well.

 

[J0hnnyD]

I simplified it to P1V1=P2V2 and solved for P1 and got the answer. Anyone know how to find the depth of the diver given all these variables?

 

[Mapes]

Hi J0hnnyD, welcome to PF. Do you know how to find the hydrostatic pressure at a certain depth in a fluid?