Charging and discharging of capacitors

• thereddevils
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.

thereddevils

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 ?

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

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 ?

The charges can not jump to one plate of a capacitor onto the other one.

ehild

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 .

No, the charges can move only in the wires which connect one pole of the battery to one plate of the capacitor.

ehild

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 ?

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

Yes.