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10. When the overhead cables reach the area where the electricity is
required for use, the voltage must then be carried by much heavier
conductors, which have to be well insulated and are therefore more
costly.
11. A simple thermionic valve is called a diode because it has two
electrodes: the cathode, which is negative, and the anode, which is
positive.

EXERCISE 6 Divide the text into portions according to the
sense and entitle them

EXERCISE 7 Parts of the text are mixed up. Arrange the
portions consequently according to the
contents.

EXERCISE 8 Write the summary of the text and prepare an
oral report: “The Nature of Electricity”.

EXERCISE 9 A. Translate the text “Solar Energy”.

SOLAR ENERGY

Shortage of energy is a major world problem and experts
predict that the present rate of increase in energy use could exhaust
the supply of fossil fuels in the twenty-first century. What the
world needs is a source of perpetual energy.
Potentially, we have a source of perpetual energy shining
down on us. The sun. On clear day in the tropics, the intensity of
solar energy can be more than a kilowatt per square metre at mid-
day. That amount of energy falling on an area of sixty-four square
kilometres is about as much as the whole of the British electricity
generating system produces.
There is no charge for the energy that flows so freely from

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