Charging and discharging of capacitors

In summary, an isolated conductor is not connected to anything and can still have a charge Q. When a positively charged capacitor is brought near an earthed conductor, some of the negative charges will move to the positive plate and vice versa. The amount of charge on the capacitor will remain constant, as charges can only move through conducting contact. When a capacitor is connected to a battery, charges can only move through the wires connecting the battery and the capacitor's plates.
  • #1
thereddevils
438
0
The questions says an isolated conductor has charge Q ...

is isolated the same as uncharged ? If so , how can it have charge Q ?

Also , if an earthed conductor is brought near a positively charged capacitor , some of the negative charges will move to the +ve charged capacitor and vice versa , so would the charge still remain constant ? Or the amount of charge that leave the capacitor equal the amount that came in ?
 
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  • #2
Isolated means that the conductor is not connected to anything.

A capacitor usually has two plates, with equal and opposite charges. What do you mean on positively charged capacitor?

Charges can move to one body to an other one if there is some conducting contact between the objects. ehild
 
  • #3
ehild said:
Isolated means that the conductor is not connected to anything.

A capacitor usually has two plates, with equal and opposite charges. What do you mean on positively charged capacitor?

Charges can move to one body to an other one if there is some conducting contact between the objects.


ehild

could it be that the positively charged capacitor have positive charges on both plates ? Then when it is brought near to a negatively charged conductor , the charges will move across each other right ? Then will the amount of charges on the capacitor the same now ?
 
  • #4
The charges can not jump to one plate of a capacitor onto the other one. ehild
 
  • #5
ehild said:
The charges can not jump to one plate of a capacitor onto the other one.


ehild

what if it is connected to a battery ? I thought the battery would pump the charges around .
 
  • #6
No, the charges can move only in the wires which connect one pole of the battery to one plate of the capacitor.

ehild
 
  • #7
ehild said:
No, the charges can move only in the wires which connect one pole of the battery to one plate of the capacitor.

ehild

oh , so the charges can only move to the other side of the plate through the battery ?
 
  • #8
thereddevils said:
oh , so the charges can only move to the other side of the plate through the battery ?

Yes.
 

What is a capacitor?

A capacitor is an electronic component that stores electrical energy in the form of an electric field. It consists of two conductive plates separated by an insulating material, or dielectric.

How does a capacitor charge?

A capacitor charges when it is connected to a power source, such as a battery, and an electric current flows through it. This causes one plate to accumulate a positive charge and the other plate to accumulate a negative charge, creating an electric field between them.

What is the equation for calculating the charge on a capacitor?

The equation for calculating the charge on a capacitor is Q = CV, where Q is the charge in coulombs, C is the capacitance in farads, and V is the voltage across the capacitor in volts.

How does a capacitor discharge?

A capacitor discharges when it is connected to a circuit that allows the stored energy to be released. This can happen when the capacitor is connected to a load, or when the circuit is opened, causing the capacitor to discharge through the path of least resistance.

What is the time constant of a capacitor?

The time constant of a capacitor is a measure of how quickly a charged capacitor will discharge. It is defined as the product of the resistance and capacitance in a circuit, and is typically represented by the symbol τ. The time constant determines the rate at which the capacitor will discharge, with a larger time constant resulting in a slower discharge and a smaller time constant resulting in a faster discharge.

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