A lamp mainly emits light of wavelength `lambda`. The lamp is rated at P
Channel: Doubtnut
Date: 2020-08-02

A lamp mainly emits light of wavelength `lambda`. The lamp is rated at P watt and 8% of the energy is emitted as visible light.  (i) How many photons of light are emitted by the lamp per second?  (ii) How many photons are falling per second on a square whose length of each side is a, held perpendicular to the incident photons at a distance r from the lamp.