WHAT IS GAUSS'S LAW?

[elevated]

I'm a senior in high school, and I have a physics research paper due on Thursday. The problem is, I don't know what Gauss's Law is.

So I googled it.
In physics, Gauss's law gives the relation between the electric flux flowing out a closed surface and the charge enclosed in the surface.

I still don't know what it is.

Can someone explain in laymen's terms please?

Thanks
Ed

 

[mugs]

http://en.wikipedia.org/wiki/Gauss%27s_law
http://www.google.com/search?sourceid=n...A,DVXA:2004-39,DVXA:en&q=gauss%27s+law

(In other words, I have no idea, but he has a button named after him on CRTs )

 

[her209]

You're screwed.

 

[Goosemaster]

Originally posted by: her209
You're screwed.

 

[elevated]

Originally posted by: Goosemaster

Originally posted by: her209
You're screwed.

<3anandtech

 

[Ketteringo]

I had this last term and I don't even remember, lol.

 

[Rock Hydra]

/creeps out of thread slowly

 

[Heisenberg]

The integral of E dot da is equal to the charge enclosed divided by the permittivity of free space. Basically the sum of the component of the electric field lines normal to any closed surface is equal to the amount of charge inside the surface divided by the permittivity constant. Think of a point charge of magnitude q inside a sphere of any radius. Add up the electric field lines exiting the sphere and you will have exactly charge q (divided by the permittivity constant).

 

[The J]

Heisenberg has it down.

Basically, if you have an enclosed surface (not solid!), then the electric flux through it is the integral of E dot dA or 4(pi)kq.
k = Culomb's constant or ~8.99x10^9
q = the amount of charge that the closed surface encloses.

Electric flux is the the amount of the electric field that "flows" through a given surface area. This is given by E dot dA (dot product), where dA is the vector associated with the piece of surface area (the vector's magnitude is equal to the surface area of the piece it's referring to). The direction of dA is perpendicular to the surface. Both E and dA are vectors.

Remember that E dot dA = |E||dA| cos X , where X is the angle between E and dA.

 

[elevated]

Originally posted by: The J
Heisenberg has it down.

Basically, if you have an enclosed surface (not solid!), then the electric flux through it is the integral of E dot dA or 4(pi)kq.
k = Culomb's constant or ~8.99x10^9
q = the amount of charge that the closed surface encloses.

Electric flux is the the amount of the electric field that "flows" through a given surface area. This is given by E dot dA (dot product), where dA is the vector associated with the piece of surface area (the vector's magnitude is equal to the surface area of the piece it's referring to). The direction of dA is perpendicular to the surface. Both E and dA are vectors.

Remember that E dot dA = |E||dA| cos X , where X is the angle between E and dA.

thanks heisenberg and The J. I have figured out, slowly but nonetheless figured out what Gauss's Law means, but are there any real-life analogies or situationst hat utilize Gauss's Law? I'm supposed to be able to talk for 10 minutes about this. So far I have enough information for 30 seconds.

Ed

 

[BMdoobieW]

is that like the thing that says when you try to hold back a stinky it will inevitably come out?

 

[RaynorWolfcastle]

Originally posted by: Heisenberg
The integral of E dot da is equal to the charge enclosed divided by the permittivity of free space. Basically the sum of the component of the electric field lines normal to any closed surface is equal to the amount of charge inside the surface divided by the permittivity constant. Think of a point charge of magnitude q inside a sphere of any radius. Add up the electric field lines exiting the sphere and you will have exactly charge q (divided by the permittivity constant).

As usual Heisenberg gives the correct explanation pertaining to someone's physics homework. Don't you get tired of it?

Applications, eh? Well Kirchoff's current law (widely used) is essentially an application of Gauss' Law. Apart from that, Gauss' law is often used when calculating things related to capacitors. Can't really think of all that many direct applications, but I'm sure there are more.

 

[Evadman]

Yofor your speach, you could go into some of the projects that ameatur hobiests can do with a through understanding of Gauss's law, such as a gauss cannon / coil gun. They're fun

 

[IGBT]

..something about flux and fields isn't it??

 

[arcenite]

*degauss*

 

[ElFenix]

*loads up MW4 to fire the guass canon*

 

[Heisenberg]

Originally posted by: RaynorWolfcastle
As usual Heisenberg gives the correct explanation pertaining to someone's physics homework. Don't you get tired of it?

Applications, eh? Well Kirchoff's current law (widely used) is essentially an application of Gauss' Law. Apart from that, Gauss' law is often used when calculating things related to capacitors. Can't really think of all that many direct applications, but I'm sure there are more.

Not really. It's so rare I actually know what the hell's going I that I don't mind sharing.

As for applications, Gauss's Law is one Maxwell's equations (there are four total). Those four equations govern electricity and magnetism completely. So really any piece of modern electronic technology we can make today comes, at least in part, from Gauss's Law.

 

[Dudd]

Yeah, I dropped Electrical and Magnetic Physics and get to take it again next semester, so good luck and no help from me.

 

[jadinolf]

Originally posted by: RockHydra11
/creeps out of thread slowly

joins him........

 

[Rock Hydra]

Originally posted by: jadinolf

Originally posted by: RockHydra11
/creeps out of thread slowly

joins him........

I never learned this stuff in High School physics.

 

[computeerrgghh]

My physics book has a picture of water sprinklers and drains. Around the sprinklers is a sphere that has somehting to do with flow? And aroudn the drain is a sphere where water flows out. I dunno what it means still so take it for what its worth.

 

[elevated]

haha thanks all for your great insight and help, i'll get to work tonight