Conductors in Electrostatic Equilibrium | Rules for Electric Fields | Doc Physics
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- Опубликовано: 6 янв 2025
- This video lists and sorta explains the rules of conductors so you can solve problems. If you still wonder why charges like pointy bits, please view my video (and the ensuing glorious discussion with other nerds in the comments) right hurre: • Electric Potential of ...
Why on earth is that incredibly elegant explanation of charge distribution on the outside of a conductor absent from my Physics textbook?
Maybe the authors wanted to make you more struggle than they did.
Why am i laughing and having fun learning physics
Because u need to go for phyciatrist😂
as a white person, can confirm.
y'all are blessed with such hair
Helpful......was banging my head trying to understand it from book👍
how is an 11 year old video still so helpful
That is right😊❤
so happy I found this and I don't need to buy a book to understand my lame teacher.
At 9:34 ....how do the charges cluster up , shouldn't like charges repel and wouldn't that sort of disturb the equilibrium with a flow ?
A simple explaination for the accumaltion of charges at sharper regoins is as follows: charges move due to potential from high to low untill the potential is equal and electrostatic equilibrium is reached, now the potential is inversly proportional to the raduis and thus more chage is required where pot is = (k*q)/r.
Your lectures are generally very clear (thank you for them), but this is the first I've been confused by. 1) is the excess charge on the surface of the conductor or on the outside of the conductor? 2) can you have both lone electrons & lone protons on the surface/outside or just one?
I thought electric feild arrows point towards negative charges...is that wrong? Because 9:11 confused me.
The Truth I was simply defining the direction that was out from the surface. You are correct that E points the opposite way.
I got my answer sir, thank you so much for uploading the video.
9:50 umm.. why are the field lines going out from the -ve charge
just field just normal direction. perpendicular to surface .
Good catch, should be pointing in
Loool, A white persons hair! This is a great series! Thanks a ton!
This is an astoundingly good question! We're all scientists here - please do some research and get back to me.
On an even more serious note, I've seen white people who wear long straight hair. If you look at these people from a meter away, you might come to the conclusion that their hair is always parallel to their head. BUT NO! Look closer and be surprised. Electric fields are similarly misleading. Now go get those Mexican people.
Hi .....plz can you tell me how u set ur camera
i like ur energy while explaining
why perpendicular electric field cant make charge to move ? i mean E=F/q therefore the charges on surface must move out of the conductor...also if positive charges are in the surface where the negative are ?...i cant get it..help pls
Here's my potential explanation of the "pointy bits":
The answer lies not in the pointy bit itself, but in the area around the pointy bit. Since electric fields point at a tangent away from a conductor's surface, they will influence each other a lot in the area just around the pointy bits since they curve *into each other*.
This means that the electrons in that area are closer to each other than normal, instead of curving outwards like they would in a sphere. Because of this, the electrons in that immediate area would push each other away, either congregating in the pointy bits or evenly distributing on the rest of the conductor's surface.
So maybe we're not just looking at a lot more electrons on the pointy bits, but also at a lot fewer electrons in the areas just next to the pointy bits and a few more electrons on the rest of the conductor's surface.
Love how the blue marker was feeling left out and rolled in @4:43 lol
Shouldn't the outer charges repel with the incoming charges from the inside?
Education at it's finest!
Doc, why did you draw positive charges relocating to the surface after stating that protons don't move? How are positive charges (I'm assuming of course that we're talking about protons) moving if they're "trapped" in the atoms of the metal? Also, is it that there is no NET charge on the inside, or no charge on the inisde? Thanks!
No net on the inside, for sure. And it can look like positive charges migrate to the surface when negatives in fact leave the surface!
Why don't the charges distribute evenly throughout the conductor like most other things in equilibrium (ions in a solution). Wouldn't the high concentration of positive charges on the surface repel each other back into the interior of the conductor?
yes it due to repelsion
@9:49 Look at the distance from the tip to the bulb is greater than across the thin section. Formula, similar to m sub 1 m sub 2 / r^2
Hi Joe. You have totally missed my point.
And how did I get called risqué and "PC wussy" for the same statement? Ah, the internets.
Why electrons do not fly off the surfaces of a negatively charged body?
is the conductor always hollow? Please help
But wont the negative charges on the surface repel the electrons that are moving from inside towards the surface :\ ?
+Redwan Mahmud Yes, but so are the (many more) on the opposite side of it. The net effect of all charges on the outside is zero.
I didn't get why ground is like upper postive and lower negative ?
The reason why there are more charges at the "pointy bits" is because of this:
Imagine 2 spheres with a radius (r). Both have linear surface distribution( σ ).
So for Sphere 1 we have σ1= Q1/S1 and for Sphere 2 we have σ2= Q2/S2...
These 2 spheres have potentials V1= (σ1*r1) / ε0 and V2= (σ2*r2) / ε0
Let's pretend that V1=V2=V that means
(σ1*r1) / ε0 = (σ2*r2) / ε0
.... ε0 cancel out so we have
σ1*r1 = σ2*r2
=> σ1/σ2 = r2/r1
From this we see that the raport of surface distributions is inversely proportional with the bending radius of the 2 points on the surface. So that means the "pointy bitiER" the object it, the more charges it will have.
but for a conductor it's surface charge density is constant all over right?
No it is not , it's potential is constant everywhere but not surface charge density
Ya definitely rt
Why would electrons (negative) move from a surface where there is already a deficit of electrons to the inside of the conductor where there is also a lack of electrons. Shouldn't they stay on the surface?
would like to know the answer too. Please reply if you have found it.
MIND BLOWN
just what I needed to understand, thanks
it seems that if there are lone electrons & lone proteons, they will always draw each other until there are only lone charges of one kind or the other. e.g. at 5:05, if there were no lone proton in the middle, the lone electrons on the surface would still be attracted by both lone protons on the surface and one would link with the lone electron. so, i don't see how there could be both lone protons & lone electrons on the surface.
Electric fields in a conductor are perpendicular to the surface because if they were not, there would be a component of the electric field parallel to the potential direction of motion of the electrons inside the conductor. This would cause acceleration, but of course, this cannot be the case due to the net electric field inside the conductor being zero.
Nice I really impress bro
I like it!
9.42, I think for(-) charge configuration... The field lines should be radially inward.
Am I listening to Michael Scott?
Why Electric field should be normal for a perfect conductors? My guess - any tangential Electric field will cause movements(they can move freely) in charges in outer surface. So if they are stationary they must have the field normal.
If lightning strikes that rod it will burn the conducting wire like a midnight dream. Not conventional wire can withstand the current from lightning. Its not there for lighting to strike it lol
Hey Vsauce, Michael here
I think it like this.E = σ/(2ε) = q/(2εS).
In pointy things at the very top.
S → 0
lim(S → 0) E = lim(S → 0) q/(2εS) =∞
(🙏 help me)
A conductor has deficiate of 45electrons find the charge on that conductor
ultra plus all
I think here the formula will be ...q = ne
Here n is 45 and e is charge on electron
6:00 why not black person
I'd say it's more like a native aborigninal papaguinean's hair
I LOVE U
Your reasoning in the "counter example" (2:45) is poor & clumsy and not based on real physics. By your reasoning, as the interior charges approach the surface then repulsion from the surface should predominate and tend to send the charges back into the interior. Giving notice to electrons at the surface doesn't help because there are electrons everywhere--not just at the surface. Nevertheless, you made up for this with the "white people's hair" analogy--that was cute!
md65000 No - it's cool. At least allow me a spherical object - the charges on the surface won't cause a net force on charges on the interior by symmetry. And you know I'm talking about electrons that are net charges. I agree it's clumsy, though. I'm trying to get the kids some things they can grab onto mentally.
It's a lot more likely that the electrons reconfigure geometrically within their atoms to keep away from each other as much as possible. After all, it's not as if the conductor will suddenly change elements just because of electrons moving around (because then you'd have to start breaking atoms to move electrons at that distance).
At higher level orbitals you start getting these types of geometric movements because the electron is getting far enough away from the nucleus. It's why most good conductors start at higher levels on the periodic table (higher number on the periodic table = more orbital levels).
yyyeah
If you wanna be super fancy. He literally just added a line.
do mexican people's hair do something different?
i heard that shit he said (7:30) and was shook.
like don't ALL people have hair?
doesn't all hair grow perpendicularly to the surface of the scalp?
like bro. why make it abt race and color?
you have a wider audience than that.
U MY F"IN DUDE MAN< FOR EVER GREAT FUL - austin sandoval
I don't get why people are getting salty over the white people comment, it was a good joke and memorable, and rule 3 is always gonna be in my head cause of that.
Projection.
Brilliant
Zlatan likes this.
Listening at 0.3
2020
hahahah love it
I have better explanation for last fact, its very easy😚
i dnt get it
😈😈😈😈😈
never mind. sorry. i think i see it.
As a white person from Africa, I feel racist towards me.
racist sala
first u r indian .. second he is talking about his people . he himself is white. the way you do on your chai stalls ..
How is he being racist when he's talking about his own people? One: he's being creative. Something your own Physics teacher lacks a lot. And two: that example alone helps us get a clear idea on how electric field looks and behaves like. It's not like he insulted white people. There is a huge difference! Sheesh...
chutiya hai?
I’ve never ever understood a word from this guy. Seems like I’ll just stick to Khan Academy.