A laser pointer emits a continuous beam of red light of power at a wavelength of
PHYSICS · Subjective · A Level · Physics · Particles and radiation · Particles and radiation
Problem
A laser pointer emits a continuous beam of red light of power 5.0mW at a wavelength of 650nm.
(i) Find the energy of one photon in the laser beam.
(ii) Determine the number of photons emitted by the laser per second.
(iii) If the beam remains switched on for 10s, calculate the total number of photons emitted in this interval.