Electric potential of a conductor.

In summary, the definition of electric potential is the work done to bring a test charge from infinity to a particular point. The potential of a charged conductor refers to the potential of all points on the conductor, whether on the surface or underneath. Bringing an earthed object close to a charged conductor can decrease the potential of the charged object as the earthed object gains positive charge and compensates for the potential due to the charged conductor. The charge distribution on the outer surface of a spherical metallic shell is always uniform, regardless of the position of a charge inside the shell, due to the zero electric field inside the conductor.
  • #1
Terocamo
47
0

Homework Statement


I know the definition of electric potential is the work done to bring a test charge from infinity to a particular point.
But I read about some question asking the electric potential of a charged conductor,
I wonder what that means, whether it is the potential of the surface of the conductor or otherwise.

Also, I don't understand the concept of bringing a earthed object close to a charged conductor will
decrease the magnitude of potential of that charged object.
eg. my notes mention the induced charge inside the eathed object contrubutes a positive potential
to make the potential of the negative charged conductor LESS negative. Itsn't an earthed object
have zero potential? So how can it contrubute any potential.

Thz :blushing:
 
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  • #2
Terocamo said:

Homework Statement


I know the definition of electric potential is the work done to bring a test charge from infinity to a particular point.
But I read about some question asking the electric potential of a charged conductor,
I wonder what that means, whether it is the potential of the surface of the conductor or otherwise.
What do you mean by "otherwise"? A conductor is an equipotential which means that all points that make up this conductor whether on the surface or underneath the surface are at the same potential.

Also, I don't understand the concept of bringing a earthed object close to a charged conductor will
decrease the magnitude of potential of that charged object.
eg. my notes mention the induced charge inside the eathed object contrubutes a positive potential
to make the potential of the negative charged conductor LESS negative. Itsn't an earthed object
have zero potential? So how can it contrubute any potential.

Thz :blushing:
The earthed conductor is always at zero potential. If you bring it close to a negatively charged conductor, free electrons inside the earthed conductor will be pushed into the Earth as they are repelled by the negative charges on the other conductor. The loss of negative charges in the earthed conductor raises the potential of the negatively charged conductor because it is essentially a gain of positive charge in that region of space.
 
  • #3
kuruman said:
The loss of negative charges in the earthed conductor raises the potential of the negatively charged conductor because it is essentially a gain of positive charge in that region of space.

Thz first, you clear some of my wrong concepts, but i am still puzzled by how the potential is raised.
I now understand the earthed object gains positive charge and produce a field to compensate
the potential due to the negative charge conductor in order to maintain zero potential. (I hope
thats a right concept :bugeye:)
Is it that potential due to the earthed object raised the potential of the charged object? :confused:
 
  • #4
Ive got another question about electric field.

There is a spherical metallic shell of uniform thickness which is neutral. A positive charge is put inside it
but not anywhere close to the centre of the spherical shell. Why is it the charge deposit on the outer and inner surface of the
shell distrubute unitformly?
Itsnt the electrostatic force stronger if closer? I thought the negative charge will gathered
at a pt close the the positive charge and it will disturb the distrubution of charge.
 
  • #5
Terocamo said:
Is it that potential due to the earthed object raised the potential of the charged object? :confused:
Yes. The potential of the earthed object is always zero.
 
  • #6
Terocamo said:
Ive got another question about electric field.

There is a spherical metallic shell of uniform thickness which is neutral. A positive charge is put inside it
but not anywhere close to the centre of the spherical shell. Why is it the charge deposit on the outer and inner surface of the
shell distrubute unitformly?
The charge on the outer surface only is distributed uniformly if the charge inside the cavity is off center. To get uniform distribution on the inner surface, you need to have the charge in the center. You can change the charge distribution on the inner surface by moving the charge in the cavity around, but that does not affect the charge distribution on the outer surface because the electric field inside the conductor is always zero so the inside distribution cannot communicate to the outside distribution what is happening to it.
 
  • #7
Thz again, it is very helpful.
 

What is electric potential?

Electric potential is a measure of the potential energy per unit charge at a specific point in an electric field. It is measured in volts (V).

How is electric potential different from electric potential energy?

Electric potential is a measure of the potential energy per unit charge at a specific point, while electric potential energy is the total potential energy of a charge in an electric field. Electric potential is a property of the electric field itself, while electric potential energy is a property of the charge in the field.

How is the electric potential of a conductor related to its charge?

The electric potential of a conductor is directly proportional to its charge. This means that as the charge on a conductor increases, its electric potential also increases. However, the shape and size of the conductor can also affect its electric potential.

What is the significance of the electric potential of a conductor?

The electric potential of a conductor is important because it determines the movement of charges within the conductor. Charges will always move from areas of higher potential to areas of lower potential, so the electric potential of a conductor can affect the flow of electric current.

How can the electric potential of a conductor be calculated?

The electric potential of a conductor can be calculated using the equation V = kQ/r, where V is the electric potential, k is a constant, Q is the charge on the conductor, and r is the distance from the conductor. This equation assumes a point charge, so for more complex shapes, a different equation or a numerical method may be needed.

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