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Snowcat [4.5K]
3 years ago
15

Lasers are now used in eye surgery. Given the wavelength of a certain laser is 514 nm and the power of the laser is 1.1 W, how m

any photons are released if the laser is used for 0.056 s during the surgery?
Physics
1 answer:
Leno4ka [110]3 years ago
5 0

Answer: 1.593*10^{17} photons released if the laser is used 0.056 s during the surgery

                           

Explanation:

First, you have to calculate the energy of each photon according to Einstein's theoty, given by:

                            E =\frac{hc}{\lambda}

Where \lambda is the wavelength, h is the Planck's constant and  h is the speed of light

              h = 6.626*10^{-34} \frac{m^{2} kg }{s}  -> Planck's constant

              c = 3*10^{8} \frac{m}{s}  -> Speed of light

So, replacing in the equation:

                E =\frac{ 6.626*10^{-34} \frac{m^{2} kg }{s}*3*10^{8} \frac{m}{s}}{514*10^-9 m}

Then, the energy of each released photon by the laser is:

                E = 3.867*10^{-19} \frac{J}{photons}

After, you do the inverse of the energy per phothon and as a result, you will have the number of photons in a Joule of energy:

               \frac{1}{3.867*10^{-19}} = 2.586*10^{18} \frac{photons}{J}

The power of the laser is 1.1 W, or 1.1 J/s, that means that you can calculate how many photons the laser realease every second:

              2.586*10^{18}\frac{photons}{J} * 1.1 \frac{J}{s} = 2.844*10^{18} \frac{photons}{s}

And by doing a simple rule of three, if 2.844*10^{18} photons are released every second, then in 0.056 s:

            0.056 s*2.844*10^{18} \frac{photons}{s} = 1.593*10^{17} photons are released during the surgery

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Explanation:

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3.54 = 0.1 . X x 203.29

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Substitute mc = 0.2 kg, c = 0.3kJ/kg.K, T1 = 25 + 273, T2 = -34 + 273

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<u />

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