ShmoopTube

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And here's your shmoop du jour brought to you by flash

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bulbs flash bulbs were important when cameras were just cameras a long long [Cameras flashing]

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time ago like back in the 90s it really helped cavemen get good selfies with [caveman taking selfie with wolly mammoth]

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the woolly mammoths.... Chris walked into the living room to find his pet cat, Admiral

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Snugglesworth playing the piano Chris wants to capture the moment but the [Admiral the cat playing piano and Chris tries to take picture]

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battery on his camera phone is dead he rushes up to the attic finds an old

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flashbulb camera and makes it back down just in time to snap a photo of the [Chris using flashbulb camera]

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Admiral the energy used to produce the flash is stored in a capacitor the flash

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pulse has the power of 100 thousand watts and a duration of .001

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seconds and the potential difference be across the capacitor plates is held

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constant at 200 volts, energy is stored in a capacitor with a capacitance of C at a [physics formula]

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potential difference V determine the capacitance of the capacitor assume all

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the energy stored in the capacitor is converted into energy for the flash and

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here are the potential answers..different kind of flash... All right, [potential answers and the Flash appears]

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look not to sound jaded but we've seen all the pictures of cats playing the

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piano the internet is built on piano playing cat pics is any image search [internet page of cats playing piano]

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will prove sorry Chris but without video evidence of the Admiral playing

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Beethoven's ninth were not impressed but a flashbulb camera that we are impressed [Chris takes picture of girl with flashbulb camera]

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with it's like a historical artifact from a simpler time okay, enough about

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cats and cameras.. in order to solve this problem we first need to find out how [two hands with sparks in between]

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much power we're dealing with. Since all the energy in the capacitor is used by

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the flash if we can figure out how much energy is needed to blind poor Admiral [Admiral being photographed by Chris]

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Snugglesworth then we can figure out the total energy we're dealing with well

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energy equals power times time in this case we have a hundred thousand watts of [Energy formula shown on blackboard]

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power used in one, one thousandth of a second and that means the total energy

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is a hundred joules we were already given the equation to calculate the

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stored energy we just need to arrange that equation to find the capacitance [equation for stored energy rearranged]

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starting with the equation U sub E equals one half CV squared we find that

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C equals 2U sub E over V squared plugging in the numbers we find that the

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capacitance equals five microfarads which means the correct answer is D

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if we ever have a pet talented enough to actually play an instrument we're going [Admiral playing the piano and jumps on Chris]

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to be very careful taking pictures the last thing we want from her is to get

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camera shy because we finally get the paparazzi's attention we've always [paparazzi taking snaps of Admiral and Chris]

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wanted.

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