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JEE Main20241 Feb 2024Evening ShiftPhysicsDual Nature of MatterActual

Monochromatic light of frequency 6 × 10 14 Hz is produced by a laser. The power emitted is 2 × 10 - 3 W . How many photons per second on an average, are emitted by the source? (Given h = 6 . 63 × 10 - 34 J s )

Options

  1. A9 × 10 18
  2. B6 × 10 15
  3. C5 × 10 15
  4. D7 × 10 16

Correct answer

C. 5 × 10 15

Step-by-step solution

Energy of a single photon is given by, h ν . Therefore, power can be written as P = n h v ⇒ n = P h ν = 2 × 10 - 3 6 . 63 × 10 - 34 × 6 × 10 14 = 5 × 10 15

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