- •Part I
- •Text. Physics and physical phenomena
- •Laboratory Exercises
- •Additional Material
- •M. V.Lomonosov
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Measurement of Volume
- •Text. The metric system
- •Dimensions of a Solid Body
- •Laboratory Exercises
- •Additional Material
- •Origin of the Metric System
- •Text. The kinetic theory and the three states of matter
- •3 Not to matter — не иметь значения will make full use — займут
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Mass and weight
- •3. Much, more, the most; little, less, the least; good, bet ter,
- •4, .,. Er than, more ... Than
- •5. At, on, over .., etc.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text, force, work, energy and power
- •Exercises
- •Additional Material
- •1. Have supported, has altered....
- •2. Energy can be converted...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Isaac Newton
- •Text. Heat
- •1. Heat is known to be a form of energy.
- •2. You place, you placed, you have placed. They take, they took, they have taken.
- •3. Newton began to think about heat.
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Transmission of heat
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Good and Bad Conductors of Heat
- •Text. Calorimeters
- •1. It is usual to transfer ...
- •2. There is; is there; there is no ...
- •3. The setting up of ...; the reading of ...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Wave motion and sound
- •1. It does not move forward but returns again...
- •2. It is evident, it is clear.
- •Exercises
- •Additional Material
- •Text. Light
- •1. It becomes red-hot, it is the reason, it was cold...
- •2. High temperature produced by..., in a substance called... . Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Reflection and refraction of light
- •1. Do bodies emit? Does he make? Did it represent?
- •2. Have they shown? Had he travelled? Was it reflected? Is he going? Exercises
- •Laboratory Exercises
- •Additional Material
- •Text. Lenses
- •1. After leaving the lens...
- •Exercises
- •Additional Material
- •Text. Simple cell
- •1. The twitching of; the reading of...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Voltaic Cells
- •Text. The accumulator
- •1. A plate containing, a plate being immersed...
- •2. Achieved by connecting; determined by testing...
- •Exercises
- •Additional Material
- •Text. Principle of electric motor
- •1. They are used to pull...
- •2. When viewed, while doing...
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Electric Bell Circuit
- •Text. Moving-coil ammeter and voltmeter
- •Exercises
- •Laboratory Exercises
- •Additional Material
- •Moving-Coil Galvanometer
- •Text. Electromotive force
Laboratory Exercises
8. Listen and read the following word combinations:
unlike metals, copper and zinc discs, the whole arrangement, a number of such cells, dilute sulphuric acid, an electromotive force, potential difference, a small torch bulb, the terminals of the copper and zinc, the main cause of the polarization, hydrogen gas, a high electrical resistance.
9. Listen and repeat in pauses:
About 1800 Volta made a great discovery and invention. One pair of copper and zinc plates with brine between them forms a unit or cell. The cell has an electromotive force or potential difference of about 1 volt. When the cell is working hydrogen is produced at the copper plate. This is the main cause of the polarization.
10. Listen to the following questions on the above text and answer them:
1. When did Volta make a great discovery? 2. What forms a unit or cell? 3. What has the cell? 4. Where is hydrogen produced?
11. Ask questions using the model.
Model: Hydrogen is produced at the copper plate.
What is produced at the copper plate?
1. Hydrogen gas has a high electrical resistance. 2. The cell is said to be "polarized". 3. The bulb lights up for a time.
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12. Suggested topics for oral narration:
1. Explain the meaning of the terms a) an electromotive! force, b) polarization, as applied to a simple cell.
2. Describe briefly how a simple cell, consisting of a copper electrode and zinc electrode dipping into dilute sulphuric acid, works.
Additional Material
Read the text and get its central idea. Distinguish series and parallel grouping of cells.
Voltaic Cells
A voltaic cell consists of two dissimilar plates immersed in a solution that acts chemically upon one of them. Local action in a voltaic cell is caused by miniature circuits set up between carbon impurities from the zinc plate itself. It is usually remedied by amalgamating the negative plate. Polarization is a defect in a voltaic cell due to the accumulation of hydrogen bubbles on the positive plate. The hydrogen may be destroyed by the use of the oxidizing agent; or, by the use of some mechanical device, it may be kept from coming into contact with the positive plate.
Cells are grouped in series or parallel. Series grouping gives the better results when the external resistance is large; parallel grouping is better when the external resistance is small compared with the internal resistance.
Read the texts and translate them without using a dictionary. Draw diagrams and describe how to connect cells in series and parallel.
How to Connect Cells in Series
Connect three dry cells in series. Note that the outside terminal of each cell is connected to the centre terminal of the next cell or vice versa. When the cells are connected in this way, to total voltage or electrical pressure is the sum of the voltages of the cells. In the case, when there are three cells, the total voltage is 4.5 volts since the voltage of each cell is 1.5 volts.
Now connect the two lead wires to a lamp for a three-cell flashlight. Disconnect one of the wires and attach the same
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lamp to a single cell. Note the difference in brightness. Connect the same lamp to two cells in series and compare the brightness with that produced by one cell and by three cells.
How to Connect Cells in Parallel
Connect three cells in parallel by attaching all the centre terminals to one wire and all the outside terminals to another wire. Connect the lead wires to a receptable and insert a bulb for a one-cell flashlight.
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