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JEE Main 20241 FebruaryEvening Shift
Exam
JEE Main
Year
2024
Date
1 February
Shift
Evening Shift
Subject
Physics
Chapter
Dual Nature of Matter

JEE Main 2024 · 1 February · Evening Shift · Physics · Dual Nature of Matter

Monochromatic light of frequency 6 × 10 ^ 14 Hz is produced by a...

Monochromatic light of frequency 6×1014Hz6 \times {10}^{14}Hz is produced by a laser. The power emitted is 2×10−3W.2 \times {10}^{- 3}W . How many photons per second on an average, are emitted by the source?

(Given h=6.63×10−34Jsh = 6 . 63 \times {10}^{- 34}Js)

Options

  1. A9×10189 \times {10}^{18}
  2. B6×10156 \times {10}^{15}
  3. C5×10155 \times {10}^{15}
  4. D7×10167 \times {10}^{16}

Correct answer

C. 5×10155 \times {10}^{15}

Step-by-step solution

Energy of a single photon is given by, hνhν. Therefore, power can be written as 

P=nhvP = nhv

⇒n=Phν=2×10−36.63×10−34×6×1014⇒ n = \dfrac{P}{hν} = \dfrac{2 \times {10}^{- 3}}{6 . 63 \times {10}^{- 34} \times 6 \times {10}^{14}}

=5×1015= 5 \times {10}^{15}

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