Absorption and reflection of light by glass

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awh97
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Report Thread starter 7 years ago
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I need to do an experiment on measuring the absorption of light by glass for Physics coursework, but don't know how to prevent the results being compromised by reflection. Is there a way to prevent reflection, and if not, how do I measure the amount of light reflected. Also, I am planning to use multiple glass blocks placed next to each other, so will increasing number of blocks increase the amount of light reflected, or will only the first block cause reflection, as this is where the light is entering a new medium?
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Joinedup
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what are you planning on varying in your experiment?

afaik it's safe to assume the reflection at the first air glass boundary is a constant proportion of the incident photons provided you keep everything else constant, this means you can attribute all changes in the dependent variable to the variable you're adjusting.

wrt reflection between the blocks, it'll happen every time the photons cross a boundary between materials with different refractive index, the classic solution used by lensmakers is to stick the elements together with a special optical cement (glue) with a matched refractive index to the glass components.
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paddyman4
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I don't know what measuring devices you are planning on using. If you use a laser as input and a light detector, then you can fire the laser such that it hits the block at an angle. Measure the light that is reflected and the light that comes out the other side of the block. You should also measure the amount of energy emitted by the laser by firing it straight at the detector. So then knowing the light emitted by the laser, you subtract the measured reflected light and subtract the measured transmitted light to get the absorbed light. You should also measure the background light levels without the laser being on to see what your base level is.
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