WEBVTT
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What is the momentum of a 4.00-centimetre-wavelength photon?
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We can call the wavelength of this photon ๐.
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And we want to solve for its momentum, which weโll call ๐.
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To begin, we can recall the relationship for the momentum of a photon.
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Photon momentum ๐ is equal to Planckโs constant โ over photon wavelength ๐.
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Planckโs constant weโll treat in this problem as exactly 6.626 times 10 to the negative 34th joule seconds.
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So ๐ equals โ over ๐.
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And when we plug in for these two values, being careful to use units of metres in our expression for ๐ and calculate ๐, we find that to three significant figures itโs 1.66 times 10 to the negative 32 kilograms metres per second.
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Thatโs the momentum this photon has.