At the given point of time, the earth receives energy from sun at `4 cal cm^(-2) mi n^(-1)` .Determine the number of photons received on the surface of the Earth per `cm^(2)` per minute. (Given `:` Mean wavelength of sun light `= 5500 Å` )

Explanation

Number of photons received on the surface of the earth, from `E = nhv |{:(E = "4 calorie"),("= 4 xx 4.184 J),(lambda = 5500 Å):}`
`n = (E lambda)/(hc)`
` = (4 xx 4.184 xx 5500 xx 10^(-10))/(6.6 xx 10^(-34) xx 3xx 10^(8)) = (9.2048 xx 10^(-10))/(19.8 xx 10^(-26)) = 4648xx 10^(16)`
` = 4.648 xx 10^(19)`
` n = 4.65 xx 10^(19)`