A 100 W point source emits monochromatic light of wavelength `6000 A` Q. Calculate the photon flux (in SI unit) at a distance of 5m from the source. Given `h=6.6xx10^(34)`J s and `c=3xx10^(8)ms^(-1)`A. `10^(15)`B. `10^(18)`C. `10^(20)`D. `10^(22)`

A 100 W point source emits monochromatic light of wavelength `6000 A`

1.	A 100 W point source emits monochromatic light of wavelength `6000 A` Q. Calculate the photon flux (in SI unit) at a distance of 5m from the source. Given `h=6.6xx10^(34)`J s and `c=3xx10^(8)ms^(-1)`A. `10^(15)`B. `10^(18)`C. `10^(20)`D. `10^(22)`
Answer» Correct Answer - B Intensity (i.e., energy flux) at a distance of 5m from the source of power P, `I=(P)/(4pir^2)=(100)/(4pixx5^2)=(1)/(pi)(W)/(m^2)` The number of photons passing normally per unit area per second i.e., Photon flux `=(I)/(E)=((1)/(pi))/(3.3xx10^(-19))approx10^(18)` photons `m^(-2)s^(-1)`

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A 100 W point source emits monochromatic light of wavelength `6000 A` Q. Calculate the photon flux (in SI unit) at a distance of 5m from the source. Given `h=6.6xx10^(34)`J s and `c=3xx10^(8)ms^(-1)`A. `10^(15)`B. `10^(18)`C. `10^(20)`D. `10^(22)`

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