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Hurry And here's your smoke too Sure brought to you

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by day dreams We don't daydream We maintain focus at

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all times and never let our imaginations run away Because

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we're always dedicated Tio What was that Sorry Drifted away

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there from all right Tear the following passage and image

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Here we go jakes learning about electric current in class

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But the monotonous voice of the teacher sends jake into

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a daydream Imagine shrinking down to the size of an

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electron In exploring the wire jake abruptly wakes up when

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his teacher asked him are you paying attention Howto electrons

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behave Jake replies Well they're pretty cool They go with

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the flow in his dream when a potential difference is

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set up across the ends of the wire jake and

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the electrons all started bumping along in the same direction

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The current the wires calculated with the equation i equals

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nada que where N is the number of charged particles

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per unit Volume is the cross sectional area of the

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wire is the drift velocity of the particles and cue

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is the charge on each particle brought to you by

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american express Yeah All right The cylindrical wire above has

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a radius of zero point five millimeters The electrons have

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a speed of be equals one millimeters per second and

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a density of unequal six times ten to the twenty

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eight meters to the negative third what's the magnitude and

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direction of the conventional current in this wire and hear

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the potential answers all right Interesting Well when we daydream

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were usually in a spaceship headed to mars not wearing

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clothes or we're making the winning shot at the buzzer

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Yeah like that We don't dream about being an electron

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and a wire but we don't judge jake here he's

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going to solve the world's problems and we're grateful were

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given most of what we need here were given number

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of particles see were given the radius of the wire

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And with that we were able to find the area

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of the cross section with a little old school gym

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called pi r squared remember that didi Yeah area and

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because we're dealing with some crazy big numbers will make

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it a little easier on ourselves and round pie down

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to three Oh and will express the radius in meters

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rather than millimeters keep everything in the same firm we're

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given The drift velocity which is one millimeter per second

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or one meter times ten to the negative third per

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second We're not given the charge of each particle but

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we know that we're dealing with electrons Electrons are teeny

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tiny little particles with a tv tiny electrical charge Their

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charges so tiny in fact that they produce the smallest

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possible unit of charge called the elementary charge or just

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eat elementary charge is produced by protons and electrons The

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proton is all smiles with a positive elementary charged electrons

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so they don't go in for all that positive attitude

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stuff they're always negative Negative negative twenty four seven Yeah

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like that real downer Sad mood The elementary charge of

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one electron is one point six two one seven six

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five seven times ten to the negative nineteen who longs

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Yeah but like electricity we try to take the path

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of least resistance So we'll round that up to times

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ten to the negative nineteenth Cool Okay we've got our

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numbers and we can plug him into our equations Quick

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reminder Current equals the number of charged particles per unit

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of volume times the cross sectional area of the wire

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times The drift velocity the particles times the charge of

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each particle Got that Now if you think and we

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have our density six times ten to the twenty eighth

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meters to the negative third we have our area three

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times point five times ten to the negative Thirty meters

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squared You have our velocity one meter times ten to

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the negative Third per second And we have our charge

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two times ten to the negative nineteenth cool arms putting

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in the numbers just looks like this and it's pretty

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ugly And we can clean that up a little by

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taking care of the square in the middle making the

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area equal three times point two five times ten to

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the negative six meters square And when we do the

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math or have our fancy pants calculated to the mat

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for us we come up with an answer of a

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charge of nine films per second A nine amps Look

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at us making progress All right One last part of

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the puzzle is knowing which direction the current is going

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in this wire We're dealing in terms of conventional charge

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which assumes the charge is positive Well positive charge moves

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from higher potential towards lower potential Those since a has

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a higher potential than be the conventional current is making

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a beeline towards b b line and say we did

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there get it pretty good All right now if we're

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talking in terms of electron flow it'd be the opposite

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But we're not talking about electron flow so don't sweat

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that right now after all of this were able to

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definitively state that the answer is there's A current of

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nine amps headed towards you shouldn't worry if we daydream

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little it's actually an important part of the scientific process

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It also prepare us for a nobel prize speech Yeah 00:04:48.867 --> [endTime] now that's some great daydreaming

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