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A monochromatic source emitting light of wavelength 600 nm has a power output of 66 W. Calculate the number of photons emitted by this source in 2 minutes. |
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Answer» Solution :Energy of one photon `E=(hc)/(lambda)` `E=(6.6 xx 10^(-34) xx 3 xx 10^(8))/(6 xx 10^(-7))` `=3.3 xx 10^(-19)` J `E_(1)="energy emitted by the source in one second"` = 66 J `:.` Number of PHOTONS emitted by the source in 1 sec., `n=(66)/(3.3 xx 10^(-19))` `= 2 xx 10^(20)` `:.` TOTAL number of photons emitted by source in 2 minutes, `N=n xx 2 xx 60` `= 2 xx 10^(20) xx 120` `= 2.4 xx 10^(22)` photons |
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