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JEE MAIN 2019
10-04-2019 S2
Question
A 2 mW laser operates at a wavelength of 500 nm . The number of photons that will be emitted per second is: [Given Planck's constant $\mathrm{h}=6.6 \times 10^{-34}$ Js, speed of light c $\left.=3.0 \times 10^8 \mathrm{~m} / \mathrm{s}\right]$ $\_\_\_\_$
Select the correct option:
A
$2 \times 10^{16}$
B
$1.5 \times 10^{16}$
C
$1 \times 10^{16}$
D
$5 \times 10^{15}$
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
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