Refractive index of air depends on temperature and pressure

Last updated: 6/21/2023

Refractive index of air depends on temperature and pressure Within few metres of height difference near the ground air pressure remains almost uniform but air temperature changes by appreciable amount Suppose under such conditions the refractive index u depends only on the temperature and this dependence has the form a 1 T Here a is a constant value of which at normal pressure is 1 6 K The sun heats up the air above a road and simultaneous random small movements of air make the dry asphalt appear like a puddle This phenomenon is called mirage Suppose that in a thin layer immediately above the road temperature of air is AT 20 K more than temperature To 300 K of the air elsewhere From what minimum horizontal distance x an observer of height h 1 75 m can see a puddle on the road otic T Al