Практическая работа № 8 electric cells

Цели: Введение и активизация в речи лексики по теме «Электрические элементы».

Оборудование: комплект тестов, раздаточный материал.

Vocabulary

I. Learn the words and expressions.

Cell элемент

Output емкость, мощность

Bulb электрическая лампа

To light зажигать, освещать To substitute увеличивать (ся), возрастать

. . . and so on и так далее

II. Read and translate the text.

An electric cell is used to produce and supply electric energy. It consists of an electrolyte and two electrodes. Electrodes are used as terminals, they connect the cell to the circuit - current passes through the terminals and the bulb lights.

Cells can be connected in series, in parallel and in series-parallel. In order to increase the current capacity cells should be connected in parallel. In order to increase the voltage out­put cells should be connected in se­ries. In case a battery has a large current capacity and a large voltage output, its cells are connected in se­ries-parallel.

When cells are connected in series the positive terminal of one cell is connected to the negative terminal of the second cell, the positive terminal of the second cell - to the negative terminal of the third ... and so on.

W

hen cells are connected in parallel their negative terminals are connected together and their positive terminals are also connected.

In case a cell has a trouble it stops operating or operates badly. This cell should be substituted by another one

III. Find English equivalents.

Элемент, мощность, увеличиваться, ячейка, электролит, электрод, способность, объединять, позитивный, негативный.

IV. Add necessary letters.

Cel-, lig-t, sup-ly, thro-h-, vol-age, capa-ity, term-nal, sub-tit-te.

V. Finish the sentences.

1. An electric cell is used…………

2. It consists of…………

3. Cells can be connected……………..

4. Electrodes are used……………….

5. When cells are connected in series………….

6. When cells are connected in parallel………….

7. In case a cell has a trouble……….

VI. Make up the sentences.

1. to produce supply cell energy is and An electric electric used

2. can be series, parallel in connected Cells series-parallel in and in

3. When together and positive terminals cells their are connected their negative in parallel terminals are also are connected connected.

4. stops operating In has a badly trouble or operates it case a cell

VII. Solve these problems:

1.Suppose that you have four electric cells. The current capacity of each cell equals 1.5 amp, the voltage output equals 2 V.

1. Connect the cells in series. In what way should it be done?

2. Connect the battery to a circuit whose resistance value equals 15 ohms. What is the value of current in the circuit?

2. Suppose that you have three cells of the same value.

1. Connect them in parallel. In what way should it be done?

2. Connect the second battery to the same circuit: what will it result in?

Suppose that one of the cells stops operating. What should be done in this case?