Unit 6 nature of electric current.

In the modern conception matter is composed of atoms. The atoms are made up of a positive nucleus surrounded by negative charges of electricity, called electrons, which revolve around the nucleus at tremendous speed. The nucleus consists of a number of protons, each with a single positive charge, and, possibly a number of neutrons, which have no charge. The atom is neutral when it contains equal number of electrons and protons. A negatively charged body contains more electrons than protons. A positively charged body is one which contains fewer electrons than its normal number.

When the two ends of a conductor are connected to two points at different potentials, such as the terminals of a battery, we say that there is an electric current in the conductor. What actually happens?

The conductor has equal numbers of positive and negative charges in its atoms, and we want to know how the charges can be made to produce a current. The atoms in metals are packed so closely that they overlap to some extent, so that it is comparatively easy for the outer electrons to pass from one atom to another if a small force is applied to them The battery causes a potential difference between the ends of the wire, and thus provides forces that make the negative electrons in the wire move toward the point of higher potential. This electron flow toward the positive electrode is the electric current. Obviously materials differ considerably in the ease at which electrons can be made to migrate from atom to atom.

The current will not flow unless there is an electric circuit. The magnitude of the current depends simply on the rate of flow of electrons along the conductor.

Завдання 1. Прочитайте текст та надайте відповіді на запитання.

1. What does the magnitude of the current depend on?

2. What is positively charged body?

3. What is negatively charges body?

4. When is the atom neutral?

5. What is an atom?

Завдання 2. Доповніть речення згідно зі змістом тексту.

1. The conductor has equal numbers of________________.

2. The nucleus consist of_________________.

3. The atoms in metals__________________.

4. The battery causes a potential difference between_______________.

5. Obviously materials differs________________________.

Завдання 3. Знайдіть у тексті синоніми та антоніми до наступних слів.

A) антоніми:	B) синоніми
1 positively	1 to make
2 to connect	2 tremendous
3 different	3 to migrate
4 easy	4 force
5 small	5 to differ

Завдання4. Виберіть речення, які відповідають змісту тексту.

1. The atom is made up of a negative nucleus.

2. The conductor has equal numbers of positive and negative charges in its atom.

3. The current will flow unless there is an electric circuit.

4. In the modern conception matter is composed of atoms.

5. A negatively charged body contains equal numbers of electrons and protons.

Завдання 5. Складіть речення з поданих слів.

1. the positive electrode, is, flow, the electric current, the electron, toward

2. consists of, neutrons, the nucleus, one as more

3. made up, a positive nucleus, is, the atom, of

4. to know, can be made, we, to produce, how, want, the, charges, a current

5. in, overlap, to some, the atoms, metals, extent