Question

Monochromatic light of frequency 5.0 × 10¹⁴ Hz is produced by a laser. The power emitted is 3.0 × 10^–3 W. Estimate the number of photons emitted per second on an average by the source ?

Answer 1

Energy = hν
On an average, number of photons emitted per second  =\[\frac{\text { Power}}{\text { energy of one photon}}\]

On putting the values:
On an average, number of photons emitted per second

\[= \frac{3 \times {10}^{- 3}}{6 . 63 \times {10}^{- 34} \times 5 \times {10}^{14}}\]

\[ = 9 . 05 \times {10}^{15}\]