Monochromatic light of frequency |MODERNPHYSICSJEEMAIN2023

JEE MAIN 2024

01-02-2024 S2

Question

Monochromatic light of frequency $6 \times 10^{14}$ Hz is produced by a laser. The power emitted is $2 \times 10^{-3} \mathrm{~W}$ W. How many photons per second on an average, are emitted by the source ? (Given h=$6.63 \times 10^{-34} \mathrm{Js}$ )

Select the correct option:

$9 \times 10^{18}$

$6 \times 10^{15}$

$5 \times 10^{15}$

$7 \times 10^{16}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution

$\begin{aligned} & \mathrm{P}=\operatorname{nh} v \\ & \mathrm{n}=\frac{\mathrm{P}}{\mathrm{h} v}=\frac{2 \times 10^{-3}}{6.63 \times 10^{-34} \times 6 \times 10^{14}} \\ & =5 \times 10^{15}\end{aligned}$

Question Tags

JEE Main

Physics

Easy

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