In astronomical observations, signals observed from the distant stars are generally weak. If the photon detector receives a total of `3.15xx10^(-18)J` from the radiations of `600 nm`, calculate the number of photons received by the detector.

Explanation

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`