An inverted bell lying at the bottom of a lake 47.6 m deep has 50 cm3 of air trapped in it. The bell is brought to the surface of the lake. The volume of the trapped air will be (atmospheric pressure = 70 cm of Hg and density of Hg = 13. 6 g / cm3)
According to Boyle's law, pressure and volume are inversely proportional to each other i.e. p∝1v⇒P1V1=P2V2⇒(P0+hpwg)V1=P0V2⇒V2=(1+hpwgP0)V1⇒V2=(1+47.6×1×100070×13.6×1000)V1[As P2=P0=70 cm of Hg=70×13.6×1000]⇒V2=(1+5)50 cm3=300 cm3