A red laser with a wavelength of 670 nmnm and a blue laser with a wavelength of 470 nmnm emit laser beams with the same light power. How do

Question

A red laser with a wavelength of 670 nmnm and a blue laser with a wavelength of 470 nmnm emit laser beams with the same light power. How do their rates of photon emission compare

in progress 0
Khang Minh 5 months 2021-08-25T19:14:49+00:00 1 Answers 2 views 0

Answers ( )

    0
    2021-08-25T19:16:36+00:00

    Answer:

    red laser emits 1.42 times the number of photons of the blue laser, per unit of time

    Explanation:

    In order to calculate the rates of photon emission for both wavelengths, you take into account that the power of the light is given by the following formula:

    P=\frac{E}{t}=\frac{hc/\lambda}{t}        (1)

    That is, the power is the energy per time.

    h: Planck’s constant

    c: speed of light

    λ: wavelength of the light

    The number of photons emitted per unit of time is given by:

    n=\frac{P}{E}

    P: power of the light

    E: energy of the light

    For the two wavelengths you have

    n_1=\frac{P_1}{hc/\lambda_1}\\\\n_2=\frac{P_2}{hc/\lambda_2}\\\\\frac{n_1}{n_2}=\frac{\lambda_1}{\lambda_2}   (2)

    Where you have use that P1=P2

    Finally, you replace the values of the wavelengths in the equation (2):

    \frac{n_1}{n_2}=\frac{670nm}{470nm}[tex]\ = 1.42\frac{photons}{s}[/tex]

    Then, the red laser emits 1.42 times the number of photons emited by the blue laser

Leave an answer

Browse

Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )