Physics help, i'm having a little trouble understanding what the potential of something is.

[cirthix]

A conducting spherical shell of inner radius B and ourter radius C is ocncentric with a small metal sphere of radius a<b. The metal sphere has a positive charge +Q. The total charge on the conducting spherical shell is -Q. (a) What is the potential of the spherical shell? (b) What is the potential of the metal sphere?

Can someone help please?

 

[cirthix]

when i posted this, somehow i knew my bad joke would get rejected and this thread would get mocked, hijacked, or ignored

 

[Mo0o]

I dont get it. This is a joke?

 

[Atheus]

Originally posted by: Mo0o
I dont get it. This is a joke?

If so, I don't get it.

 

[cirthix]

Originally posted by: Mo0o
I dont get it. This is a joke?

no, i made another thread that was a joke a couple of minutes ago (this isnt being sarcastic)

 

[JohnCU]

potential relative to what?

 

[cirthix]

Originally posted by: JohnCU
potential relative to what?

that's what i can't figure out. i typed the homework question word for word from the book

 

[JohnCU]

use Gauss's law and integrate the electric field, they prolly mean absolute potential. i can't remember, let me look it up.

yeah, V = - integral(Edot(dl)

 

[cirthix]

Originally posted by: JohnCU
use Gauss's law and integrate the electric field, they prolly mean absolute potential. i can't remember, let me look it up.

yeah, V = - integral(Edot(dl)

is that legal? potential=-flux?

 

[JohnCU]

Originally posted by: cirthix

Originally posted by: JohnCU
use Gauss's law and integrate the electric field, they prolly mean absolute potential. i can't remember, let me look it up.

yeah, V = - integral(Edot(dl)

is that legal? potential=-flux?

that's not flux, since you aren't integratating over a surface.

 

[cirthix]

Originally posted by: JohnCU

Originally posted by: cirthix

Originally posted by: JohnCU
use Gauss's law and integrate the electric field, they prolly mean absolute potential. i can't remember, let me look it up.

yeah, V = - integral(Edot(dl)

is that legal? potential=-flux?

that's not flux, since you aren't integratating over a surface.

could you walk me through it a little more?

 

[l Xes l]

EA = Q/e(0)
there lies your answer...
i seriously dont know why they are asking for potential in such question...
they should be asking about flux, E. field, or charge density on surface, etc...

 

[Mo0o]

No. The potential is... the work it takes to bring a test charge from infinity (where potential is assumed to be zero) to, im assuming the surface of the shell and then the sphere. The shell should be zero potential because if you include the sphere, the net charge is zeor, making a e field eminating from the system zero.

To find V of the surface of the sphere should just be kQ/r

 

[JohnCU]

Originally posted by: Mo0o
No. The potential is... the work it takes to bring a test charge from infinity (where potential is assumed to be zero) to, im assuming the surface of the shell and then the sphere. The shell should be zero potential because if you include the sphere, the net charge is zeor, making a e field eminating from the system zero.

To find V of the surface of the sphere should just be kQ/r

yeah, he's right, set up a gaussian surface around the sphere and you'll see it.

man, i wish i had studied emag more.

 

[PurdueRy]

Find the E field between the sphere and shell. Then take the line integral of that from the sphere to the shell.

 

[PurdueRy]

E = arEr = ar Q/(4(pi)epsR^2)

V = - int(E dot dl) from r1 to r2

 

[PurdueRy]

Final equation:

(Q/(4*pi*eps0))*(1/R1-1/R2)

 

[Rubycon]

I thought this thread had potential.

 

[cirthix]

Originally posted by: PurdueRy
E = arEr = ar Q/(4(pi)epsR^2)

V = - int(E dot dl) from r1 to r2

isnt EA=4pikQ=Q/e0?

 

[PurdueRy]

Originally posted by: MS Dawn
I thought this thread had potential.

until you posted

 

[Mo0o]

Originally posted by: MS Dawn
I thought this thread had potential.

I find it pretty electrifying myself.

 

[PurdueRy]

Originally posted by: Mo0o

Originally posted by: MS Dawn
I thought this thread had potential.

I find it pretty electrifying myself.

I enjoy conducting a discussion on E field theory

 

[cirthix]

Originally posted by: Mo0o

Originally posted by: MS Dawn
I thought this thread had potential.

I find it pretty electrifying myself.

why am i not SHOCKED by these responses?

 

[Mo0o]

Originally posted by: cirthix

Originally posted by: Mo0o

Originally posted by: MS Dawn
I thought this thread had potential.

I find it pretty electrifying myself.

why am i not SHOCKED by these responses?

I have a certain attraction to these exercises of wit

 

[PurdueRy]

Originally posted by: Mo0o

Originally posted by: cirthix

Originally posted by: Mo0o

Originally posted by: MS Dawn
I thought this thread had potential.

I find it pretty electrifying myself.

why am i not SHOCKED by these responses?

I have a certain attraction to these exercises of wit

if only I had the capacitance to retain the knowledge...