Question

Monochromatic light of frequency 6.0 × 10¹⁴ Hz is produced by a laser. The power emitted is 2.0 × 10⁻³ W. Estimate the number of photons emitted per second on an average by the source

Answer 1

Energy = hν

power is the energy per unit time  therfore the energy given per second is  = `2xx10^-3`

On putting the values, we get:

number of photons * energy of one photon = total energy

number of photons=`(2xx10^-3)/(6.63xx10^-34xx6xx10^14)`

=`5 xx 10^15` photons