[" On the bottóm of lake af a depth "h=100m" ,a horizóntäl pipe of length "80" m with piston is kept as hown in "],[" the figure.The piston is light and movable.Between the piston and pipe some air is captured "(x_(0)=9m)" as "],[" shown in fig.The pipe is slowly raised to vertical position and upward as shown in fig.(ii).The lengh "],[" of air column "(x)" in SI units is "5K" .Find value of "K" .(Disregard the atmospheric pressure & piston and pipe are air "],[" tight.Temperature of gas remains constant)."]