Question

Output power of He-Ne LASER of low energy is 1.00 mW. Wavelength of the light is 632.8 nm. What will be the number of photons emitted per second from this LASER ? h = 6.25 x 10⁻³⁴ J s.

Answer 1

Answer:

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Answer 2

Answer:

$3.37\times 10^{16}$

Explanation:

Output power of LASER, P = 10 mW

                                           $=\ 10\times 10^{-3}$

output energy of LASER, E = power x time

                                             $=\ 10\times 10^{-3}\times 1\ J$

                                           $=\ 10\times 10^{-3}\ J$

wavelegth of the light produced by LASER,

$\lambda\ =\ 632.8 nm$

            $=\ 632.8\times 10^{-9}\ m$

              $=\ 6.32\times 10^{-7}\ m$

according to formula,

$E\ =\ \dfrac{n.h.c}{\lambda}$

$=>\ 10\times 10^{-3}\ =\ \dfrac{n\times 6.25\times 10^{-34}\times 3\times 10^{8}}{6.32\times 10^{-7}}$

$=>\ n\ =\ 3.37\times 10^{16}$

Hence, total number of photons emitted by LASER in one second is $3.37\times 10^{16}.$