Neutral conductor has a hollow cavity within it

[TwinCamGTS]

Homework Statement

a neutral conductor has a hollow cavity within it. When a point charge q = +6.3 nC is placed into this cavity

How much charge will be found on each surface of the conductor?

inner: -6.3 nC (negative charge being attracted by the positive charge that being put in the cavity)
outer: 6.3 nC ( positive charge being pused to the outer radius)

if the conductor is grounded.

Charge on conductor surfaces:
inner: -6.3nC (negative charge being attracted by the positive charge that being put in the cavity)
outer: 0 nC ( because its being grounded, so positive charge travel to lower potential energy)

If the conductor was initially not neutral but has its own net charge of q2 = +4·q

Charge on conductor surfaces:
inner: . nC
outer: . nC

Homework Equations

no equation, its aconceptual questions

The Attempt at a Solution

i thought since the conductor is has more charge +4*q than the point charge , that means it will have -4*q as well. that means the point charge will not be able to pull electron near it. so inside charge will be -0 charge and outside will be +6.3
but I am wrong

then i think, well, maybe the point charge will be able to pull a fraction of - charge towards the cavity, so the charge inside will be -6.3 and outside will be 3*(6.3)=18.9

its wrong too

can someone kindly explain it to me? thank you for your time and reply

 

[Dick]

Homework Statement

a neutral conductor has a hollow cavity within it. When a point charge q = +6.3 nC is placed into this cavity

How much charge will be found on each surface of the conductor?

inner: -6.3 nC (negative charge being attracted by the positive charge that being put in the cavity)
outer: 6.3 nC ( positive charge being pused to the outer radius)

if the conductor is grounded.

Charge on conductor surfaces:
inner: -6.3nC (negative charge being attracted by the positive charge that being put in the cavity)
outer: 0 nC ( because its being grounded, so positive charge travel to lower potential energy)

If the conductor was initially not neutral but has its own net charge of q2 = +4·q

Charge on conductor surfaces:
inner: . nC
outer: . nC

Homework Equations

no equation, its aconceptual questions

The Attempt at a Solution

i thought since the conductor is has more charge +4*q than the point charge , that means it will have -4*q as well. that means the point charge will not be able to pull electron near it. so inside charge will be -0 charge and outside will be +6.3
but I am wrong

then i think, well, maybe the point charge will be able to pull a fraction of - charge towards the cavity, so the charge inside will be -6.3 and outside will be 3*(6.3)=18.9

its wrong too

can someone kindly explain it to me? thank you for your time and reply

You can think about this a little more accurately if you use use the Gauss theorem. What does that say? Add to that there is no electric field inside of a conductor.