In asstronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15 xx 10^(-8)J from the radiations of 600 nm, calculate the number of photons received by the detector.

In asstronomical observations, signals observed from the distant stars

1.	In asstronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of 3.15 xx 10^(-8)J from the radiations of 600 nm, calculate the number of photons received by the detector.
Answer» Solution :Energy of one photon `= hv = h (c)/(lamda) = ((6.626 XX 10^(-34) Js) (3 xx 10^(8) ms^(-1)))/((600 xx 10^(-9) m)) = 3.313 xx 10^(-19) J` Total energy received `= 3.15 xx 10^(-8) J` No. of PHOTONS received `= (3.15 xx 10^(-18))/(3.313 xx 10^(-19)) = 9..51 ~~ 10`