Rub one end of a glass rod with a silk cloth, then touch

Question: 1. Rub one end of a glass rod with a silk cloth, then touch the rod to one piece of Styrofoam and the silk cloth to the other Styrofoam piece, the two Styrofoam pieces attract each other. Explain? (Enter your answer here)

2. If we rub a plastic rod with fur and then bring the rod near the glass rod (rubbed with silk above), the two rods attract each other. Explain?

3. What are conductor, insulator, semiconductor and superconductor materials?

4. What does “Charge is quantized” mean?

5. What is the conservation of charge?


1. The glass rod gets positively charged when rubbed with silk cloth and the silk cloth gets negatively charged.When the rod is touched with styrofoam piece it gets positively charged same as glass rod.The other styrofoam piece gets negatively charged touched with silk cloth.Since opposite charges attract each other the two styrofoam pieces attract each other.

2.When a plastic rod rubbed with fur , the fur gets positively charged since it has a tendency of losing electron and the plastic rod gets negatively charged. Hence when the plastic rod is brought near the glass rod (rubbed with silk cloth) they attract each other since they are oppositely charged.

3.Conductors are materials which conduct electricity and it has very low resistance.Example-metals, human body ,graphite etc.

Semiconductors are materials which has a range of conductivity lower than conductor but greater than insulator. Example-Germanium,Silicon

Insulators can not conduct electricity.Examples are plastic,glass rod etc. They have a very high resistivity.

Superconductors are materials for which at certain temperature the resistivity goes to zero in zero magnetic field. Example-Mercury at 133K,aluminum at around 100K.

4.Charge quantization means charge is always transferred from one object to another as an integral multiple of electron charge.

5.Charge conservation means there is always same amount of positive charge and negative charge in the universe.That means charge can not be created nor destroyed.

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