An ideal gas in enclosed in a tube and is held in the vertical position with the closed end upward. The length of pellet of mercury entrapping the gas is `h = 10` cm and the length of the tube occupied by gas is `l=40` cm. Calculate the length occupied by the gas when it is turned through `theta= 60^(@)` and `90^(@)`. Atmospheric pressure , `H= 76` cm of mercury.