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For this exercise, we have two lasers, one infrared whose wavelength is 2 times 10 to the minus 6 meters, and one ultraviolet whose length is, whose wavelength is 7 times 10 to the minus 8 meters.
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And both lasers have a power of 200 watts, which is 200.
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Joules per hour.
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And the first question asks us, which is bigger? the energy of a single infrared photon or the energy of a single ultraviolet photon.
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So we know that the energy of a photon is given by hf, and f, the frequency, can be written as c over lambda.
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Okay, sees the speed of light.
01:01
So this means that whichever photon has the largest wavelength is going to have the smaller energy and vice versa.
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So the photon with the largest energy is going to be the one with the smaller wavelength.
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And the photon between these two, the infrared and the ultraviolet photon, the one with the shortest wavelength is the ultraviolet one.
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So the photon with the most energy is the ultraviolet one.
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Ultraviolet.
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Okay, this is the answer to question a.
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And question b asks us to calculate explicitly these two energies...