When an air bubble rises from the bottom of a lake to the surface its radius doubles. If 10 m of water column produces pressure equal to 1atm,depth of tube is ______m. a.) 10 b.)20 c.)70 d.) 80

Asked by Pooja Kulshrestha | 29th Jan, 2012, 11:07: AM

Expert Answer:

here, the temperature is constant.
so ,   P1V1=P2V2
initially the bubble was at the bottom. so P1=pr at the bottom
V1=vol at the bottom=4/3 ?R3
P2=pr at the top=atm pr
V2=4/3 ?(2R)3
SO BY SOLVING , P1V1=P2V2  after putting the values you 'll get the pressure at the bottom
that will be equal to=1atm pr+pr due to the columnof  lake.
                            =1atm pr+hdg    
                             =(10+h)dg   
P1x4/3 ?R3=P2x4/3 ?(2R)3
(10+h)dg=8x10dg
h=70 m

Answered by  | 30th Jan, 2012, 10:58: AM

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