Boyle's Law: Calculating Balloon Size at Surface After 40 m Descent

[9giddjl]

Homework Statement

A diver dives to a depth of 40 m in fresh water where he releases a toy balloon of volume 10 cm^3. What will be the size of the balloon when it reaches the surface? (The pressure increass at a rate of 1 atmosphere for every 10 m descent in fresh water)

Homework Equations

P1V1=P2V2

The Attempt at a Solution

P1= 4 atm
V1= 10 cm^3
P2= ?
V1=?

I just don't know how to find the pressure when it reaches the surface... what would the pressure be?
Thankyou:)

Kind regards

 

[CompuChip]

The pressure at the surface of the water is the outside pressure, which you can probably assume to be 1 atm. So, more or less by definition of the unit "atmosphere", P2 = 1 atm.
You might want to check your value for P1, however.

 

[9giddjl]

thankyou very much:) that makes sense:)