Electric field | Electric charge, electric force, and voltage | Physics | Khan Academy
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- Опубликовано: 5 сен 2024
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We can think of the forces between charges as something that comes from a property of space. That property is called the electric field. Created by Sal Khan.
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I watched this nearly 10 years ago, and 10 years later it is just as invaluable if not more given the current global condition. Thank you Sal. Donated :)
Dude, Sal, I don't know what it is about your voice but man it's really easy to pay attention to your voice. You have a pretty cool voice. :P
Ragd0ll ok boomer
@@ericzhou1028 Ok, Mr. Unfunny.
bro my thoughts exactly
i dont mean to be off topic but does anybody know a way to log back into an Instagram account..?
I stupidly forgot my login password. I love any help you can give me!
@Duke Tristian Instablaster =)
these are literally saving my grade right now....
I don't know if anyone's pointed it out yet (and it's not a big deal because the concept is spot-on) but around six minutes in, Sal says the E-field is 2500, but it should be 2250.
Demon519 you're correct. because 9 / 4 = 2.25 but then when you multiply that by 10 ^ 3 it becomes 2250 Newtons
still 2250, isnt it?
you are correct, girlfriend
Demon519 yeah that was funny hahaha
I agree
This might save my physics grade. Get back to you after tomorrow's exam.
+Sandra Faye Villagarcia Did it?
It sure did. :D
Fangirl Faye A lot of the stuff that I learn in my physics class isn't even on youtube which sucks lol, I'm just here for the heck of it
Fangirl Faye YOU GIVE ME HOPE! I also have an exam :)
I hope in the future only good teachers like you teach, that way student will be able to learn more efficiently.
I hope your dream come true someday but we still don't have teachers like him
Khan Sir, first day when I watch your videos I was surprised that how one can write in this way .....digitally...and today I am using it perfectly..this is because of you ...Thankful to you for this reason...
Dr Sushil Kumar Guruji so can you tell me how to write?
Your kidding right?
@@islamisthebestreligion1738 😂😂😂😂
The way I gain knowledge about an unknown topic is through Khan. If I think I can move on to the next level, that's the time I will tackle free lectures from the Universities like MIT or something, because I find their approach more general. But overall, without Khan, I have no bridge to higher thinking.
This was an excellent video. Most certainly bolstered my understanding of the concept; also definitely taught in a very intuitive and meaningful manner.
the right answer is 2250 N/C, great lesson, thanks.
It is the end of 2021 December, It is still useful, can't thank enough you have done a brilliant work bro!
this guy knows everything :)) what i search, this dude all the time appears..
Em, just want to say that 9×10^3÷4=2250. It is very helpful, though
Really wish you would redo some of these with your new and improved graphics software :/
Please, never stop your videos. Good didactics is so unbelievably rare and you are doing a great job in this field. thx for that
youtube is filled with these videos nowadays :p
You are one of the best teachers I have ever heard, and I don't even know what you look like!!
REAL definition of Electric Flux = NUMBER of acceleration lines (AL) produced by charges travelling at light speed.
Electric Field (E) = ACCELERATION = number of AL/Area = Density of AL. That's all.
I think that's one of the main reasons he's so popular. Even youtube automatic captions gets it right most of the time!! Now that's an achievement!!
he/she did it for those trying to follow along while he does the math.... thanks dude !! :)
I'm supposed to be learning this, and im too busy rewinding and laughing at "SQUALER"
At what time? I missed that lol
@@rin.rin.3024 did you find the timestamp.?
@@rin.rin.3024 4:14
Sal, it's 2250N, not 2500. Make sure to post a note in the video so this doesn't confuse someone (like it did to me :P). Thanks for the video!
2 people aren't smart enough to see the value in these videos! GREAT WORK Teach!
4:14 "Squalar" XD
I just commented in the last video about the ambiguity between using d and r! Thanks for clearing that up. Your awesome.
It is odd that we have all the mathematics, but we have no objective understanding of what charge is!
+An artist theory on the physics of 'Time' as a physical process. Quantum Atom Theory
In mathematics we study precise relationships and patterns. In science we study the relationships and patterns of nature and while we do acquire objective understanding of objects in nature, that understanding is never ultimate or final.
Well, there more of a tool to aid us in math.
could someone explane to me why that -1C, didn't make the final anawer -2500? how does writing the formula F= q*E change the negative sign?
The mouse wriggling everywhere across the screen makes it seem like sal is having a seizure during the whole video XD
I don't know why I laughed so hard when he said "squalar" lol
I like how he doesn't forget anything that would confuse us
Thank u very much, Sir. Your short videos literally made more sense than what I'm reading
My brain can comprehend this amount of information. It is like a lecture without the bullshit
Because Force it's self is a vector quantity, for example Newtons second Law states that F=m * a. In relation to electrostatics it is stating that F= q * E with q being charge and E being the field. Well when the ATTRACTION OR REPULSION of each charge has a magnitude and a DIRECTION, thus being a vector quantity, because if it just had magnitude it would only be a scalar quantity. Hope that helped.
CORRECTION...at 6:15; the E should be 2250 N/C; (9*10^3)/4 = 2250 not 2500
I'm very thankful for these videos, they are very interesting and easy to follow. However, I was wondering why the quality (in terms of resolution and drawings) is so low in some videos.
Published 11 years ago
SQUALER!!!!!!!!!!!
I'm pretty sure you could take over the world with your knowledge if you wanted to.
very very very good explanation sir
It's an amazing and enjoying explaination
this is awesome thank you soooo much...im a 43 year old who is studying for stage one physics exam next week...job well done:):):):):)
Just making sure...
E = Electro Motive Force = Voltage = Electric Field?
Thanks
..
This is a clear explanation
Wish I though of watching these videos before the test and not after. :(
I really appreciate the content but man, did you record that with a hairdryer? Pixels. Pixels everywhere.
IKR‽‽‽ its like it was made 8 years ago or something!
Iz. M. Well if it was higher res there's actually be more pixels?
So helpful, much more helpful than barron's book or anything of that sort.
As soon as I heard him say squaler, I scrolled down to see the comments hoping someone commented about it, and low and behold, a comment had been made! Another win for the YT community.
What is electric field made of? How electric force acts w/o contact.
9÷4=2.25
The fact that this video's length (13:32 )is the same as the previous is just strange...
Why do we consider the negative sign 13:10 when in the initial formula for force we were taking the absolute value?
awesome explanation .
very informative for beginners !!!
good job
The vedio's age = my age 🙂
Funny when he keep saying "I don't know" and then put a number
My physics professor, Professor Wolf at Cooper Union told us that is a common misconception that more dense field lines means a stronger electric field. Good video though!
thanx alot
AY GOD GIVE U ENERGY MORE THN U CLARIFY ENERGY CONCEPT TO US
"I should actually use a line tool...", "...but then i can't draw the arrows..." LOL so cute.
what about spherical shape? the world around us IS three dimensional... perhaps bringing up the equation to cause 3d effects?
ah this finally makes sense now, thanks!
Content is awesome as always just not happy that i cannot go beyond 240p.
At 5:59 the electric field at that point is = (9 x 1000) / 4 = 2250 Newtons per coulomb not 2500. Kinda insignificant but just pointing it out lol. Awesome video man.
u rock my world, ur getting me through uni, in fact stuff uni when i have khan academy
@ShankMasterKank LOL omg i thought i was the only one. i really like his voice!
I still can't get it how is he able to write those equations with mouse only 👏👏👏👏👏
Well, I must say you are having my attention somehow... Superb ! Thumbs Up !
I have seen all the vedios ...and I want to see some more vedios to make my concept clear......
240p shalt not hinder me on my quest
thanks, Sal is awesome!!!
with this channel,i can skip all my physics class
So electric field can never be negative? How does is show direction then?
awesome vids, but you probably should outline what you're gonna talk about beforehand. Sometimes it sounds like you're rambling, you go in one direction, then another, then you comeback. Its a tad irritating. I subscribe to you b/c you provide an alternative point of attack of the subject matter which is deeply appreciated and helpful. But try and remain focus when imparting material that is somewhat slippery to grasp. Thank you.
p.s. - Great job overall!
you've done a really great jobs ! thumb up
"the charge times the electric field is great in you" - Yoda, Master
Sal you are awesome. Thank you so much for what you do for us!
this is a great lecture
So is E the electric potential energy?
In the exercise why is -q? The charges must attract each other?
Cool. What's the difference between an electric field & electricity?
(9*10^9*1*10^-6)/4 = 2250. Use a calculator during the video if you want to or plan your lesson, but get your stuff right!
I am curious about something. At 9:17 in the explanation of field lines around Q, you say, "as you get closer to the source of the electric field the charge gets stronger" I did not know the charge gets stronger or weaker. I thought a charge was a charge, multiples of either negative or positive increments and was fixed. How does the charge get stronger? Does it accumulate more electrons?
The charge doesn't actually get stronger, the electric field does
Do Electric Fields only work with Static Electricity, or does it occur in current as well?
At 10:30 Why when a positive and negative charged object kept close for Interaction the direction of the lines go from positive to negative?
Kaushik Mishra It's really just convention. I suppose it's because we consider protons to have mass, and electrons have negligible mass, so when the two are attracted, the electrons tend to do the majority of the motion, so we say the field lines come from positive. That's my best guess. Again, it's just convention.
Kaushik Mishra Actually, given more thought: by convention, we assume the E-field is how a positive charge would be affected. The electric field can be thought of as the path a positive charge that we arbitrarily insert, would go. As such, it is repelled by the positive charge and attracted to the negative charge. Hope this helps!
Demon519 thanks. meanwhile even i got something - its actually with accordance to the direction of current and as its said that positive terminal has more potential than that of the negative terminal hence according to the concept of electric potential it flows from higher potential to lower potential in our case from positive to negative . but m not sure of the fact why positive terminal is considered to have higher potential.
+Kaushik Mishra The positive terminal doesn't have a higher potential than the negative terminal. The positive terminal lacks electrons and the negative terminal has plenty. They both are equal. A 9v battery has +9 at the positive and -9 at the negative terminal.
Arbitrarily, a positive test charge (i.e. a proton) was chosen to create the electric field line diagram so we can visualize and assign direction to charge. And it's become a convention in physics. No other reason but by choice. So what this means is that when a proton goes near a proton they will repel and when a electron goes near a proton they will attract.
+Kaushik Mishra
That the electric field always points in the direction of the force it will exert on a positive charge is a pure convention that was adopted long before we knew of the existence of protons or electrons, back in the 19th century.
I thought it was E=kQ/r... because if E=Work/Charge, and Work is equal to Force Times distance... then if you derive it in this way, you shoud get E=kQ/r instead of E=kQ/r^2
At 6 mins the electric field is 2250 N/C rather than 2500.
Great video btw
it will have no effect since they are neutrons and thus are neutrally charged
khan . . does the electric field vector fall off to a certain limit? In other words, do the vectors converge?
his voice
GRACE KING REPRESENT
I have seen a definition of field strength = F/Q, but why is that? why not F/(2Q)? or F/Q2?, is this word "strength" related to stress-strength as in mechanics?
Sir khub valo laglo
There are so many different equations for electric fields ahh
When he says electric field, does he mean electric field density ? Just wanted clarification
I have saved all your videos...if I have any doubts I look upon khan academy , it really makes us learn better ...but this video m not satisfied, u confusd me. hope u make other video of this with better explanation.....
aww you got me confused when you said 2500 n but great explanation!!!
I wish u were my teacher
why force between 2 charges is a vector quantity ????????
what happens with the direction...????
plzzz plzz explain ?????
Oh, it basically tells you whether the charges equal or opposite. The two most important directions are: Out and in.
which one is the first?
what will be the pattern of electric field lines if we consider a dipole..
What if the charge rotates
Is there a video which explains Gauss's law ?? can someone please link the video for khanacademy if there is one, or just give me the link to a video which they thought explained gauss's law properly?
5:58 That should be 2250 Newtons
Not a problem. Watch his videos and there you go :)