Assuming the density of air to be 1.295 kgm-3, find the fall in barometric height in mm of Hg at a height of 107 m above the sea level . Take density of mercury = 13.6 × 10pawer3 kg m-3.
Open in App
Solution
Let us take a cuboid of height 107 meters and a square base of area 1 m². Volume of air in this cuboid = 107 m³ mass of air in this cuboid = 107 * 1.295 = 138.565 kg
Pressure on the base of the cuboid due to the weight of air in the cuboid = ρ g h = 1.295 * g * 107 Pa = 138.565*g Pa
This is fall in pressure. Fall in the barometric height of Mercury column = 138.565 /(density of mercury) = 138.565 / 13,600 = 0.01019 meters = 10.19 mm ==============================
Height of mercury column in barometer, which is equivalent the height of air of 107 m high = 107 * 1.295 / 13,600 = 10.19 mm