- #1
Ajay.makhecha
- 10
- 0
If a conductor has a cavity in it and if a charge is placed in the cavity, then will the electric field inside it be zer
Charge placed in a cavity in a conductor
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Discussion Overview
The discussion revolves around the behavior of electric fields in a conductor with a cavity when a charge is placed inside that cavity. It explores concepts from electrostatics, particularly focusing on the implications of having a charge within a conductor and the resulting electric field characteristics.
Discussion Character
- Conceptual clarification
- Debate/contested
Main Points Raised
- Some participants assert that the electric field inside the cavity will not be zero due to the presence of a charge within it.
- One participant expresses confusion based on textbook statements that the electric field inside a conductor must be zero, questioning the implications when a charge is present in a cavity.
- Another participant clarifies that the electric field exists in the cavity because the charge acts as a source of the electric field, which is not shielded by the conductor.
- A further explanation is provided regarding charge distribution, noting that charges on the inner and outer surfaces of the conductor adjust to maintain zero electric field within the conductor material itself, while a field exists in the cavity due to the charge.
Areas of Agreement / Disagreement
Participants do not reach a consensus; there are competing views regarding the behavior of the electric field in the cavity of a conductor with a charge present.
Contextual Notes
There is a lack of clarity regarding the definitions of "inside a conductor" and the conditions under which the electric field is considered zero, particularly in relation to the presence of a charge in a cavity.
- #2
berkeman
Admin
- 69,508
- 25,062
Ajay.makhecha said:
Welcome to the PF.
The field inside the cavity will not be zero. Is there a reason that you think it would be zero?
- #3
Ajay.makhecha
- 10
- 0
Actually I just started learning electrostatics. In our texts it is mentioned that electric field inside a conductor must be 0. But nothing is mentioned if it has a charge inside it. So I just asked out of curiosity. Btw can you say why it won't be zero?
- #4
berkeman
Admin
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Ajay.makhecha said:
(I fixed "u" to "you" in your post -- we don't use text speak at the PF
)There is a field because there is a charge (source of E-field) with no conductor shielding it from the space inside the cavity.
- #5
my2cts
- 362
- 26
"Inside a conductor" in this case should be read as inside the volume actually occupied by the conductor.
It can also mean a hollow space surrounded by a conductor, in which the field is not necessarily zero.
Suppose a charge q is in the hollow space
On the inner and outer surfaces charges (-q and +q) are distributed such that the electric field inside the metal is cancelled.
Outside the metal a field exists due to the outer surface charge distribution of +q. If the conductor and the cavity are spherical and concentric,
this field will be equal to the field of a free charge.
It can also mean a hollow space surrounded by a conductor, in which the field is not necessarily zero.
Suppose a charge q is in the hollow space
On the inner and outer surfaces charges (-q and +q) are distributed such that the electric field inside the metal is cancelled.
Outside the metal a field exists due to the outer surface charge distribution of +q. If the conductor and the cavity are spherical and concentric,
this field will be equal to the field of a free charge.
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