Electric charges at rest are the subject of electrostatics. Materials that permit the free flow of electric charges normally electrons are called as conductors. Metals like copper, silver, and aluminum are classic examples.
What Happens When a Conductor is Charged?
A charge does not remain in one location when it is applied to a conductor, for as by rubbing against it or attaching it to a battery. Instead, because conductors have free electrons, they are able to travel freely.
Electrostatics of Conductors
Until these charges achieve equilibrium, they continue to move. At this time, the extra charge settles on the conductor’s surface and the electric field inside it drops to zero.
Important Properties of Electrostatics of Conductors
(a) Electric Field Inside a Conductor is Zero
A conductor’s internal electric field is always zero when it is in electrostatic equilibrium. This is because the free charges would keep moving if there was a field. We say the field is zero since they don’t.
(b) Excess Charge Resides on the Surface
Any additional charge that is applied to a conductor travels to its outside. Once more, this is a result of like charges repelling one another and attempting to separate as much as possible.
(c) Electric Field Just Outside the Surface
Right outside a charged conductor’s surface, the electric field is perpendicular to the surface. Its magnitude is given by:
E = σ / ε0
Where:
E is the electric field,
σ is surface charge density,
ε0 is the permittivity of free space.
This field is directed outward if the charge is positive and inward if the charge is negative.
(d) Conductors Are Equipotential
When a conductor is in electrostatic equilibrium, all of its points are at the same potential. Charges do not move because there is no potential difference across the conductor.
Hollow Conductors and Electrostatic Shielding
It is possible to prevent electric fields from penetrating a hollow conductor, such as a metal shell. Our term for this is electrostatic shielding. Sensitive equipment uses it to guard against outside electrical disruptions. Devices such as Faraday cages employ the principle.
• When a charge is inserted into a hollow conductor, it creates equal charges on the outer surface and opposite charges on the inner surface, leaving the outer field unchanged.
If there is no charge inside the hollow region, the electric field inside stays zero.
Induced Charges
The free electrons in an uncharged conductor reorganise when a charged object is brought close to it:
Electrostatic induction is a process that occurs without touching the conductor and occurs when electrons in the conductor travel toward a positive external charge, leaving behind positive charges.
There is a separation of charges, so far the conductor’s overall charge stays zero.
Applications of Electrostatics of Conductors
Lightning rods: Tall metal rods give lightning a secure way to enter the ground.
Protecting delicate equipment: Coaxial cables and other devices employ metal shielding to keep out outside electric fields.
Capacitors: These devices store energy and electric charge by separating conducting surfaces with an insulator.
Summary
Important facts concerning the behaviour of charges are revealed by the study of electrostatics in conductors. The special characteristics of conductors result in shielding effects, surface distribution of charges, and an internal zero fields. Designing everything from electronics to extensive electrical safety systems is made easier with an understanding of these.
Any electric field can cause free electrons in a conductor to migrate. These electrons have positioned themselves to cancel out any internal electric field when the system enters electrostatic equilibrium. As a result, a conductor’s internal electric field is zero.
Any electric field can cause free electrons in a conductor to migrate. These electrons have positioned themselves to cancel out any internal electric field when the system enters electrostatic equilibrium. As a result, a conductor’s internal electric field is zero.
Using a conductor to resist external electric fields is known as electrostatic shielding. Sensitive devices put inside a closed conducting shell are shielded from external electric impacts because the electric field inside the shell is zero. Devices like as Faraday cages employ this.
Yes, A conductor’s surface is equipotential when it is in electrostatic equilibrium. This indicates that there is no labour needed to carry a charge across the surface because the electric potential is constant throughout the surface.
Electrostatic induction occurs when a charged object is brought close to a neutral conductor. The conductor’s free charges reorganise themselves, with like charges repelling one another and opposite charges being drawn to the object. The conductor’s charge separates as a result, but the net charge stays at zero.
The electric field just outside the surface of a conductor is given by:
E = σ / ε0
Where:
- E is the electric field,
- σ is the surface charge density,
- ε0 is the permittivity of free space.
The field is always perpendicular to the surface.