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  1. Make up sentences with personal pronouns on the topic of electronics and physics. Specialist reading

  1. Read the text “Classifying Materials” and fill in the table.

Phenomenon

Definition

Conductivity

Conductor

Semiconductor

Insulator

There are many ways of classifying materials. The one we shall use here is based on the ability of a material to conduct electricity. It is known that conduction takes place as a result of the motion of charged particles, usually electrons. The ability of any material to conduct electricity is directly proportional to the number of charged particles inside the material that can be set in motion. Materials (for example metals) that have relatively large numbers of free electrons readily conduct electric current and are called conductors. Other materials having very few (or no) free electrons do not readily conduct electric current under normal conditions and are called insulators. Such materials as selenium, silicon and germanium have more free electrons than insulators, but fewer than conductors. They are called semiconductors. Conductivity depends on temperature. In metals the higher the temperature, the lower the conductivity. But in semiconductors, if the temperature rises, the conductivity increases but within certain limits. It should be realized1 that the terms “conductor” and “insulator” are not absolute, that is2 some conductors do not conduct as well as other conductors, while some insulators do not insulate as well as other insulators.

1 it should be realized – следует учесть 2 that is – то есть

  1. Read the text again and complete the sentences with the correct beginning or ending.

  1. … based on the ability of a material to conduct electricity.

  2. Conduction takes place as …

  3. The ability of any material to conduct electricity …

  4. … are called conductors.

  5. Materials having very few (or no) free electrons …

  6. Semiconductors are materials …

  7. The terms “conductor” and “insulator” are not absolute, that is

  1. Work in pairs. Ask your partner questions based on the text. Make sure you use correct auxiliary verb.

  1. Ways of classifying materials (How many?) …

  2. The ability to conduct electricity (What?) …

  3. As a result of (What?) …

  4. Is directly proportional to (General question) …

  5. Under normal conditions (Under what conditions?) …

  6. Readily conduct electric current (How?) …

  7. Such materials as selenium, silicon and germanium (How?) …

  8. It should be realized (What?) …

  1. Answer the following questions.

  1. What is conduction?

  2. What is conduction based on?

  3. What groups are materials classified into according to their conductivity?

  4. How does conductivity depend on temperature?

  5. What materials are called: a) conductors, b) semiconductors, c) insulators?