VI. Translate into Russian. Mind no:

1. There is no energy in this machine.

2. No charges move through an open circuit.

3. No material is a perfect conductor.

4. No electric machinery is used without protection.

5. No special material is needed in this case.

Speaking

VII. Answer the following questions:

1. What was Faraday interested in?

2. What are Faraday’s important discoveries?

3. What is his major discovery?

Supplementary reading

VIII. Translate and remember.

The Law of Electromagnetic Induction.

1. Faraday’s Law.

   1. The induced E.M.F. (electromagnetic field) in a conductor is proportional to the rate at which the conductor cuts the magnetic lines of force.

   2. The induced E.M.F. in a circuit is proportional to the rate of change of the number of lines of the force threading the circuit.

The induction coil, the dynamo, the transformer, and the telephone are practical applications of electromagnetic induction.

2. Faraday’s Law.

   1. The weight of a substance liberated in electrolysis is proportional to the quantity of electricity passed.

   2. When the same quantity of electricity is passed through different electrolytes, the weights of substances liberated are in the ration of their equivalent weights.

Quantity of electricity is measured in coulombs, the product of the current in amperes, and the time in seconds.

7 The Electric Charge Opposite Charges and Interactions

Reading

I. Read the following key words: lightning, characteristic, interaction, rod, positive, negative, opposite, comb, particles, cumulonimbus, thunder.

II. Read and translate the text.

Benjamin Franklin, inventor of the lightning rod, explained that positive (+) and negative (-) charges are opposite types of the same thing. Opposites are a basic characteristic of nature. They interact to show nature’s duality: positive-negative, good-bad, something-nothing.

An interesting experiment to see the interaction between opposite electric charges is that of the plastic comb and the piece of paper. Rub a plastic comb on your hair. When you do this, your hair frees electrons. These free electrons flow from your hair to the comb and, as a result, there is an excess of electrons on the comb. Next, put the comb near a small piece of paper. The comb attracts the piece of paper because the electrons on the comb repel the excess electrons and the protons in the paper attract them. This happens because different charges attract and like charges repel.

Another example of interaction between electric charges is that of lightning. During an electric storm, water and ice particles collide inside cumulonimbus clouds. As a result, the positive charges move to the top of the clouds and the negative charges move to the bottom. This movement generates static electricity. When the negative charges flow back to the positive charges they produce heat and emit light. Lightning is an electric discharge in the air. Thunder is a wave of pressure that occurs when the hot and violent lightning expands the cold air.

Vocabulary

III. Remember these words:

excess, to repel, to attract, to collide, top, bottom, heat, to emit, to expand, charge.

Grammar

IV. Circle the correct form of the verbs in brackets.

1. We (know/are knowing) that the universe has two poles.

2. Right now we (stand/are standing) on the surface of the Earth.

3. At this moment our planet (spins/is spinning) around the sun.

4. Cosmologists (believe/are believing) that gravity and electromagnetism are only one force.

5. Magnets (attract/are attracting) metals.

V. Fill in the blanks with the proper form of the verbs in brackets.

1. Scientists ______ (try) to prove that there is only one universal force.

2. The basic forces ______always _____ (interact) to construct forms.

3. Right now, millions of galaxies ______ (take) form.

4. At this moment, millions of neutrons ______ (pass) through you body.

5. What _____ you _____ (think) about?

Supplementary reading

VI. Read the information below and find out how far away from you lightning occurs.

Light travels at 300,000 km. per second. Sound travels at 340 km. per second. Light travels faster than sound.

In lightning, you first see the light and then you hear the sound. The sound occurs first but the light travels faster.

When you see the lightning, count the seconds that pass until you hear the thunder, (six seconds for example). Then multiply 340x6 to estimate the distance between you and the flash of lighting.