A laser emits a single 3.0-ms pulse of light that has a frequency of 2.83E11 Hz and a total power of 65000 W. How many photons are in the pu

Question

A laser emits a single 3.0-ms pulse of light that has a frequency of 2.83E11 Hz and a total power of 65000 W. How many photons are in the pulse? Please provide all equations and work.

6.0E23
1.0E24
2.4E25
3.6E25
4.8E26

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Khang Minh 4 years 2021-07-17T05:39:45+00:00 1 Answers 97 views 0

Answers ( )

  1. diemthu
    0
    2021-07-17T05:41:28+00:00
    Reply

    Answer:

    The number of photons in the pulse is 1.04 x 10²⁴

    Explanation:

    Given;

    frequency of the emitted photons, f = 2.83 x 10¹¹ Hz

    duration of the incident light, t = 3 ms = 3 x 10⁻³ s

    power of the incident light, P = 65,000 W

    The energy of each photon emitted is calculated as;

    E = hf

    where;

    h is Planck’s constant, = 6.626 x 10⁻³⁴ Js

    E =  6.626 x 10⁻³⁴ x  2.83 x 10¹¹

    E = 1.875 x 10⁻²² J

    let the number of photons in the pulse = n

    n(E)= Power x time

    n = \frac{Pt}{E} \\\\n = \frac{65,000 \times 3\times 10^{-3}}{1.875 \times 10^{-22}} \\\\n = 1.04 \times 10^{24} \ photons

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