38,A bulb emits light of wavelengthAHow many photons are emitted by the bulb per second?A) 3 x 10184500A. The bulb is rated as 150 watt and 8 % ofthe energy is emitted as light.1018 oronsB) 27.2 x 1012.72 x 1018

38,A bulb emits light of wavelengthAHow many photons are emitted by th

1.	38,A bulb emits light of wavelengthAHow many photons are emitted by the bulb per second?A) 3 x 10184500A. The bulb is rated as 150 watt and 8 % ofthe energy is emitted as light.1018 oronsB) 27.2 x 1012.72 x 1018
Answer» Each photon has energy ofhνh = planks constantν= frequency of lightIf there are N photons emitted then the total energy radiated isNhν.Average power is given byP=Energy/time=E/t=Nhν/tButN/t=nis the number of photons emitted per second.Therefore,n=P/hν.ν=c/λSo,n=Pλ/hcIf all the power is not radiated then the effective power = rated power x efficiency.So the number of photons emitted per secondn=Peffλ/c=P×ηλ/hcwhereη is the efficiency.In the problem power P = 150W, wavelengthλ = 4500A and efficiency is 8% = 0.08So number of photons emitted per second,n=(150×0.08450010^-10)/(6.6×10&^−34)(3×10^8)= 27.210^1827.210^18number of photons will be emitted per second by the bulb