Question

what is number of photons emitted by a 50 W sodium lamp in 5 hours where wavelength is 5893 armstrong.​

Answer 1

Ans   E=P×t

=60×10×60×60

=216×10^4  J

λ=6000  A

 =6000×10^−10  m

E=  λ /nhc

​n= Eλ /hc

= 216x 10^4x6000x10^-10/  6.626x10^-34x3x10^8

=6.5×1024   photons

hope it will help u