How electricity is produced

The most familiar way of producing static electricity is by rubbing, or friction. Rubbing together two different kinds materials that are insulators can transfer electrons from one substance to another. The substance that gains electrons acquires a negative charge, and the one that loses them acquires a positive charge. For example, rubbing a balloon against dry hair produces an opposite electric charge in the balloon and the hair (which will be drawn to the balloon). Similarly, shuffling over a carpet in dry weather will produce a sufficient electrostatic charge on a person's body to give a slight shock when the person touches a conductor.

Objects can also acquire an electric charge through a process called electrostatic induction. In the illustration Electrostatic Induction, a charged object (the negatively charged rod) is brought near an electrically insulated metal sphere, but not into contact with it. The excess electrons in the rod will repel the electrons from the part of the sphere nearest the rod to the part farthest from the rod. If electrons are allowed to escape from the sphere through an electrical connection to the ground, the sphere will be left with a net positive charge.

Current Electricity is produced by creating a difference in electric potential between two points connected by a conductor. A potential difference exists between two points when one has more electrons than the other. The point with excess electrons is called the negative terminal; the other, the positive terminal. The potential difference between the two terminals creates an electrical pressure called electromotive force (emf), or voltage.

The two most common ways of creating a voltage to produce current are chemically (using batteries) and by electromagnetic induction (using generators). A voltage can also be created by heat, light, or mechanical pressure.

The electromagnetic induction method for producing an electric current involves the use of a permanent magnet or an electromagnet. When a wire is moved through a magnetic field, the electrons in the wire are displaced and move toward one end of the wire. This action makes one end negative, the other positive.

Under certain conditions, heat will cause electrons to flow between two different materials. One device for producing this effect is the thermocouple, which is used as a measuring instrument and as a control device.

II.Составьте свой вокабуляр из слов, встретившихся при переводе текста.

III. Ответьте письменно на вопросы по тексту. Вопросы перепишите.

1) What is static electricity?

2) By what is current electricity produced?

3) Which ways of creating a voltage to produce current do you know?

IV. Найдите в тексте эквиваленты следующих слов и словосочетаний:

A charged object, rubbing, friction, an electric current, a sufficient electrostatic charge, the negative terminal; the thermocouple, the positive terminal, insulators, electrostatic induction, to repel the electrons from the part of the sphere nearest the rod to the part farthest from the rod, electromotive force (emf), electromagnetic induction method.

V. Поставьте глагол-сказуемое в нужной форме (Present, Past, Future Simple)

1. She (not/ to teach) English at school.

2. You (to meet) him yesterday?

3. The firm (to buy) new computers next month.

4. The Dean (to ask) many questions at the lecture last week.

5. Where you (to go) next summer?

6. They (to use) new scientific data for their last experiment.

7. When the concert (to be over) all the people (to leave) the hall.

8. Every year students (to take part) in scientific research.

9. The first computer (to appear) in the 1960-s.

10. If the weather (to be) fine, we (to go) to the village.

VI. Употребите правильную форму глагола в условных предложениях:

1. I (interpret) … for you at the conference tomorrow if I (be) … not already scheduled to work at the UN. I have a friend who (do) … it for you, if she (be, not) … busy. 2. If I (have) enough money, I (backpack) around Europe. But, unfortunately, I am broke. 3. If I (have) enough money in my twenties, I (backpack) around Europe. But, unfortunately, I was broke. 4. If the price of this tour to GB (come) down, more people will buy it.

VII. Переведите на английский язык, учитывая три типа условных предложений:

1. Я помогу вам, если приду рано. 2. Если бы он был осторожнее, он бы не попал в дорожное происшествие. 3. Я дам вам мой номер телефона на тот случай, если вы захотите мне позвонить. 4. Если бы она принялась учить английский еще в детстве, она бы знала его сейчас очень хорошо. 5. Если бы он не ел так много, он бы не умер так рано.

VIII. Из нескольких вариантов (1, 2, 3, 4) выберите единственно правильный.