Capacitance

[MrSnailshit]

wtf was this about -.-" i thought there would be an explanation of how capacitor works and both in AC and DC circuits ><

[swervmerv1]

Putting the units Voltage and Joules next to the d in the end of the video confused me for a while. Because it was dj and dv I thought it was a derivative. Plus having units in an equation is uncommon. Other than that great video.

[Yulesh123]

You have know idea how helpful this is for my AP test. My teacher has barely started E&M and he's rushing through it at light speed-too fast for me to understand.

[woo216]

can you please do a video on equipotentials

[modoyioP]

thank you!

[review424]

Found a simple capacitor problem to work out that deals with the capacitor's charge and energy storage. Put it in video form, until Khan makes more! Just add youtube.com to

/watch?v=4qx2mdfNibg

Let's make Khan's Academy even better!

[xsilentxXxregretsx]

soo....I have a physics test tomorrow. I'm pretty sure this is the only reason why I won't fail.

[ddr85]

k=coulomb's constant, approx 8.988x10^9 Nm^2/C^2

epsilo naught (Permittivity of free space) = approx 8.854x10^-12 F/m, or 1/(4*pi*k)

These are different constants.

[ddr85]

k=coulomb's constant, approx 8.988x10^9 Nm^2/C^2

epsilo naught (Permittivity of free space) = approx 8.854x10^-12 F/m, or 1/(4*pi*k)

[SpazzyTheEmo]

:17 - :26

He's such a spaz...

[tadm123]

capacitance and farads are the same ?

in my book they use "C" for farads, is that correct terminology?

[CaptJay12]

@tadm123 C is the symbol for capacitance and F is the symbol for the unit of Farads (which is what we measure Capacitance in)

Capacitance is to Farads as Length is to Metres you see? Sorry if that wasn't very clear...

[tadm123]

@CaptJay12 oh yea just realized Farads are the SI units of Capacitance ,thanks bro :/

[wascas15]

I'm an American going to school in Munich at the TUM....

Your videos are saving my college career :)

thanks!

[Gohamonem100times]

pretty good. u should go worldwide in electrical circuitry explanations haha seriously though

[joejacksonriley]

is "k" supposed to be epsilon zero?

[basslinet]

@joejacksonriley on 2π ;)

ask me why if you are not sure why

[uberfishy1pker]

@joejacksonriley noo its 1/(4*pi*epsilon zero)

[irondmax]

love your video.....going to whatch more later....

i have a question.........why would the neg power go the same way as the pos power?

makes no sence?

if you have a video of this please direct me

thanks

[Oneill9293]

@irondmax It's because we assume electric field lines are the direction in which a positive charge will move. A +ve charge next to a +ve plate will repel, and a +ve charge next to a negative plate will attract towards the -ve plate. Hence they're the same direction.

[irondmax]

@Oneill9293 i see thanks.

DC current flow in one direction......is that correct?

thanks again

[utsavman47]

thank you sir

[mido4life]

this is a superb lecture. thank you

[N0ha92]

greeaaaat

[Rachman01]

"Infinite uniformly charged plate" just use calculus man.. Be a man and integrate.

[abdudify]

i like it when he goes "lets ..let me see..i dont know.." really common words if you have seen many of his videos.i find it funny coz its really ironic. see .9:53

[rinwhr]

8:42, how did he get the joules? Did he replace couloumbs with joules??

[SecretAsianMan7]

@rinwhr The way he wrote it out was confusing. Basically you have

charge [coulombs] * electric field [newtons/coulomb] * distance [meters] = work [newton-meters, or joules].

The charge is 1 so it isn't included.

[VeXorian1337]

V = integral (0 -> d) ( E*dx) Where E is the electric field, d - the distance. You can derive these formulas by solving this integral.

[GotKingKongBallzz]

I'm 37 and going back to college, bro... very well explained! I mean I had to watch the video couple of times, but well worth listening too! I look forward to watching all your video... send me a link or something! I'm gonna recommend this to my class mates!

[crocorelativ]

crystal clear :) :)

[Crypton1989]

Brilliant! Got a distinction in physics cause of his teaching.

I owe you one sir. ur the reason for my A-grades :D

(Sometimes people makes things so complicated although its relatively SIMPLE)

[TBIRDS1000]

What CRAP!!! Your pic's are SHOCKING, hard to follow with the way you talk. Need to be heavily sedated before you teach!!!

[tronulu]

did just say "pie" ? lol

[mo92us]

Thank You soo soo much!!! I really hate physics and was about to drop my class, but this vid really gives me hope and Motivation.. it's all just simple and can be done!

[quidproquo2004]

@mo92us Did you pass??

[mo92us]

@quidproquo2004

yea.. Wow looking back a year ago on my comment.. I did pass. I'm a chemistry major, I'm now taking physical chemistry 2. These vids helped get me to where I am now.. I'm very close to graduating..

[veteran25]

**I am in high school right now. I discovered your videos a couple of weeks ago. I wish I discovered them earlier. I am in 12th grade and am truly scared that my college professors will go extremely fast and I wont be able to comprehend anything. With your videos I have the confidence that I can do great! You're my secret weapon against college classes!!!

[flight1510]

@veteran25

I'm in the same boat completely, except my situation is caused by an incompetent teacher not teaching us anything

[veteran25]

@flight--Thats the opposite with my class. My teacher went to MIT and Columbia University. She is a genius!

[1462895376]

Flight1510-That sounds exactly like my 12th grade AP Physics teacher too! What is up, they expect us to come into their class knowing what they know already or sumthin.

[Slimdante]

@veteran25 I'm a senior in college and these vids are still saving my arse! Best of luck. :)

[esquimalt1]

@veteran25 So how's college going?

[veteran25]

Add a video explaining dielectrics in between Capacitors. It is part of the AP physics Curriculum

[manfredcgomes]

its K all right i read it in a book.

[manfredcgomes]

if i m not mistaken capacitance= Q/V

i.e charge/electric potential (?)

help?

[TheMIkex24]

yes that's right

[calvinhobbesliker2]

They use the same letter for different things often as there are more things than letters.

[iiVI251]

if I'm not mistaken, the field lines from each individual plate seperately don't actually "bulge", only the sum of the two fields...

[readnoar]

Can anyone specifically define capacitance?

[sandphite]

Capacitance = the capability of a conductor to hold electric charge... like how a pitcher is able to hold water.

[RingoTzar]

how much charge can be stored per volt of potential difference

[123firespirit321]

Coulombs squared per joule, or

unit charge (squared) per unit energy

[Charlenegillianrox]

geez ignornat. Have you even taken physics before?

Kelvin K is a unit for temperature, but this k is a constant which is equal to 8.99*10^9

[kurrizzle]

yup yup

Coulomb's constant!

8.99*10^9

i (think) its the amount of electrons per coulomb.

[calvinhobbesliker2]

Actually, the # of electrons per coulomb is either 1.6 or 6.0x10^19

[fighterzerox]

Its not a problem.... its not K it is k = (1/(4*pi*epsilon not). And its Coulomb...

[geargfgeg]

Or maybe it's "k" you stupid ignorant fuck.

k = 1/4(pi)(8.85*10^-12 )

[desiretolearn]

I'm grateful to KhanAcademia. Keep it up.

Can someone tell me if I can download these videos? If yes then how?

Thank You.

[alcoholic007]

search for YouTube Video Ripper

[manfredcgomes]

i think u can, but i m not sure that's right thing to do.

[anava84]

Slightly confusing at first but it all comes together in the last 30 secs or so.