A 2 laser operates wavelength 500 |MODERNPHYSICJEEMain2019

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:

$2 \times 10^{16}$

$1.5 \times 10^{16}$

$1 \times 10^{16}$

$5 \times 10^{15}$

✓ Correct! Well done.

✗ Incorrect. Try again or view the solution.

Solution