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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 ?
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Solution
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
\[= \frac{3 \times {10}^{- 3}}{6 . 63 \times {10}^{- 34} \times 5 \times {10}^{14}}\]
\[ = 9 . 05 \times {10}^{15}\]
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