Penn State MTO

MTO Item Open Source License

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Electric Current

- stream of electrically charged particles passing through a given area (movement of electrons in a wire

 

 

 

 

A) Conductivity of Solids

1) Metals - contain many free electrons (good conductors)

2) Glass, fused quartz, rubber - good insulator

Few free electrons

Insulators have a High Resistivity (Structural resistance to electrons flow)

 

3) Semiconductor - a material with a resistance between conductor and an insulator

 

 

B) Conductivity of Liquids

 

1) pure liquids don’t conduct

 

2) liquid with dissolved ions conduct

(electrolyte solution)

 

(ion movement transfers charge
 not electrons)

 

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C) Conductivity of Gases

Gases conduct when ionized (charged) when exposed to:

 

a) high energy radiation

 

b) OR electric field

 

c) OR with collision with high speed particles

 

 

Charge in a gas is transferred by ions and electrons 

 

Ontario Science Centre

 

 

Plasma–very hot ionized gas

 

4th state of matter

 

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