phy electrostatics

1. As the name imples, "static" charges are charges that are immobile (i.e. do not move).

2. Certainly.
Charges of opposite sign will be attracted to the side of the (neutral) object nearer to the charged conductor.

3. The "charges" that are transferred in conductors when they are in contact are "free electrons". In sodium chloride crystals, the two ions are bounded by ionic bond. There is no free electron available for transfer.

4. The answer is "yes", because there is no perfect insulator in the world. Having said that, the charges so produced will be extremely small due to few free electrons available.



2014-02-05 13:15:27 補充：
Your suppl questions:
1. The static charges, once produced, remain on an object (this is what static means). They do not flow unless you are doing something one them, e.g. earthing the object or contacting the object with another body....
.

2014-02-05 13:16:35 補充：
(cont'd)...In fact, "static electricity" is in contrast to "current electricity". In the latter, electrons are constantly moving.

2014-02-05 13:23:53 補充：
2. Sorry...I have mistakenly thought that you refer to the neutral object.
The charge distribution of the original charged conductor does change because of the presence of the induced charge on the (originally neutral) object...

2014-02-05 13:24:07 補充：
(cont'd)...This is because the induced charges affects the potential of the conductor. This causes charges to flow in order to equalize the potential.

2014-02-05 13:28:31 補充：
(cont'd)...If the conductor is +ve charged, -ve charges will be induced on the object. The -ve charges tend to lower the potnetial of the conductor, with the side of the conductor near to the object at a potential lower than the far side....

2014-02-05 13:30:12 補充：
(cont'd)...As a result, +ve charges flow from the far side to the near side (or electrons flow from the near side to the far side) to equalize the potential.