What Is The Balance Of The Sun And Sunlight

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The Sun and sunlight
Sun is a star at the centre of our solar system, which is spherical hot plasma. Sun mainly constitutes helium and hydrogen along with other heavier elements. Sun’s energy is from fusion reaction happening between hydrogen nuclei into helium, results in emitting heat and light. Approximately 620 million metric tonnes of hydrogen is fused together each second.
Sunlight is the primary energy source for existence of life on earth. The light and heat energy from sun travels approximately 150 million kilometres to reach earth atmosphere. Total energy incident on earth atmosphere from sun consist of infrared and visible light with around 10 percent of ultra violet light. Solar constant calculated on the atmosphere accounts for about 1360 W/m2. The value reduces when reaching the land to 1000 W/m2 due to attenuation by earth’s atmosphere. Visible light is scattered by water vapour and cloud in the atmosphere. Earth’s atmosphere filters around 70 percent of the UV ,thus at the top of the earth intensity of sunlight is almost 30% more than the surface consisting of short wavelength UV rays that could cause biological damage if entered in to earth surface. To exactly find out the sunlight reaching the ground the following formula can be used:
E_ext= E_sc .(1+0.033412*cos⁡〖(2π〗 (dn-3)/365))
dn- day of the year
Esc- Solar illuminance constant = 128×103 lx
Solar constant, a measure of flux density, is the amount of incoming solar

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