# A Bulb Emits Light Of Wavelength Λ=4500 A˚. The Bulb Is Rated As 150 Watt And 8% Of The Energy Is Emitted As Light. How Many Photons Are Emitted By The Bulb Per Second?

Energy emitted by the bulb per second = $$150 * \frac{8}{100}J$$

As the energy of 1 photon = $$\frac{hc}{\lambda}$$

= $$\frac{6.626 * 10^{-34} * 3 * 10^{8}}{4500*10^{-10}}$$

= $$4.42 * 10^{-19} joule$$

Let the photons emitted by the bulb per second be x

= $$n * 4.42 * 10^{-19}$$

= $$150 * \frac{8}{100}$$

= n = $$27.2 * 10^{18}$$

Explore more such questions and answers at BYJU’S.