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Solar Constant and Important Notes

Solar constant (s)

  • Solar energy incident on unit area in unit time normally.
  • Its value is 1400 for surface of earth
  • Where R=Radius of sun, r= Distance of earth from sun, T=Temperature of sun

useful information:

  • Mercury though a liquid is heated by conduction and not by convection.
  • It is the opening that acts as a black body in Ferry`s Black body.
  • In a dark room a hot black body shines more than others.
  • Radiation emitted from a perfectly black body does not depend on the nature of its material.
  • Radiation is the fastest way of heat transfer.
  • When a green glass is heated to high temperature it will glow with the red light.
  • Birds often swell their feathers in winter because the air enclosed inside feather is bad conductor of heat.
  • We cannot boil water inside an earth satellite by convection.
  • Two thin blankets are warmer than a single blanket of double the thickness. (air trap inside the double blanket is bad conductor of heat)