Physics 36 Electric Field (10 of 18) Horizontal Line Charge

In this video I will find the electric field of a horizontal line charge.

[Flaco]

I got an A in physics 1 because of you and your videos and now I'm in the road to do the same with physics 2!!!! Thank you for these amazing videos, they're life savers!!!

[valeriereid]

I wish I could up-vote this video one million times. I mean I thought I got, then I return to watch it and now I fully get and can practice the exercises in the textbook. Thanks so much Professor, you are awesome for doing this for students everywhere.

[dhickey]

I searched everywhere to find an easy example formula of that crazy line charge diagram. You nailed it in exactly 4 minutes! Thanks so much.

[furkanekinci]

We said LANDA=Q/L okay.. But then why did we say dQ=LANDA x dX.. I think we should say dQ=LANDA x dL.. Could you explain this please

[valeriereid]

Excellent thanks so much for showing all the steps in this one. I got stuck earlier with this very question because I couldn't decide on what r^2 should be. Though I still do not know why you chose those limits of integration.

[MichelvanBiezen]

Elizabeth,
Using a and b for the limits turns this problem into a general case.  

[zackgrey]

Hi professor! Thank you for the excellent lecture. I was curious as to why we couldn't take the integral from b to b-a? That's what I initially thought the bounds should be, but ended up with

E = k * lambda * (1/b - 1/(b-a))

Which can't be rewritten into what you got. Maybe it would be the same if values were added? Thank you again for the help! You will always be my favorite physics professor.

[Heather-jpyu]

can you make one explaining non uniform charge density??

[SamuelJSantos]

I've been seeing your videos since last year, and I passed in all my subjects since then.
Thank U, teather!

[JeslieLaughs]

Yoo thank you so much this really helped soo soo soo much i dont wanna fail physics II and im going to be watching ur videos non stop .

[rishieramratan]

This video is very blurry compared to your other videos.

[frankier]

very helpful thanks, struggling in physics and youre probably saving my exam grades

[marcusaurelius]

Why dont we intergrate dE over 0 to L ?

[emircankocatepe]

I still didn't understand what is the relationship between x and dx clearly. Could anybody explain me that.

[قناةالكتابوالسنة-شح]

What do we do with the 1/a if we have a given (L=5cm, x=3cm)? With those given numbers well get b which is 8cm. So when I plug my numbers in counting the charge which is 3 nano coulombs. What do i do with the 1/a?

[reaganhambrick]

this guy has had videos that have helped me from freshman to senior year

[Artisticengineer]

Michel could you have just integrate from 0 to L to get the total electric charge?

[AndyU]

I hadn't understood whatever the hell dQ was, so I tried to hypothesize in my own way how to calculate the total electric field at a point.

What I thought was, alright, if I have a stick that is uniformly charged, there will be many charges on it, and each charge will create its own electric field, and I need to sum them all up in order to find the total electrical field. So I said, if it is uniformly charged, why do I not take the charge density (which should be charge per given point on the stick), and use it as the charge itself on cm of the stick?

σ = charge density = total charge / length of the stick or the line
a = distance from the point to the stick
L = total length of stick

E = k·σ/distance²

Etotal =

From 'distance = a' to 'distance = a+L' → ∫ (k·σ/a²) da

[suwils]

How would this problem change if this were a cylinder instead of just a line? Would the area of dQ have to be accounted for? Would this be done by including pi*r^2 somewhere?

[SuNguyen-wczi]

why are the bounds on the integral over the distance of the charge to the point of interest? Shouldn't the bounds be from the line charge itself? -(L/2) to (L/2)?