Semiconductors. Insulators

Semiconductors

Semiconductors such as silicon and germanium are used in transistors and their conductivity is halfway in between a conductor and an insulator. Small quantities of other substances, called impurities, are introduced in the material to increase the conductivity.

Insulators

A material which contains very few electrons is called an insulator. Glass, rubber, dry wood resists the flow of electric charge, and as such they are good insulating materials.

3. Read the text again and decide if the following statements are true (T) or false (F), then correct the false ones.

1. A flow of electrons moving inside a conductor creates an electric current.

2. A generator is used to move the charges.

3. Electrons can easily pass through any material.

4. Any material is a good conductor.

5. Conductors are coated with insulators.

6. The presence of free electrons affects the conductivity of materials.

7. Impurities are introduced to increase conductivity.

8. Insulating materials resist the flow of electrons.

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