Question

Temp. gradient of a gas : in a region air pressure and density are related as P/p = constant where c>1 is constant . Find the temperature gradient in the region

Answer 1

where r$Hg=13.6gc{m}^{-3}$is the density of mercury and $g=9.8ms-2$is the acceleration of gravity. The mean value of h measured at sea level is$76.0$ cm, and the corresponding atmospheric pressure is $1.013\times 105$$ kg m-1 s-2 in SI units. The SI pressure unit is called the Pascal (Pa); 1 Pa = 1 kg m-1 s-2. Customary pressure units are the atmosphere (atm) (1 atm = 1.013x105 Pa), the bar (b) (1 b = 1x105 Pa), the millibar (mb) (1 mb = 100 Pa), and the torr (1 torr = 1 mm Hg = 134 Pa). The use of millibars is slowly giving way to the equivalent SI unit of hectoPascals (hPa). The mean atmospheric pressure at sea level is given equivalently as P = 1.013x105 Pa = 1013 hPa = 1013 mb = 1 atm = 760 torr.