1. Electricity permits the creation and reception of ___ such as radio waves.
2. The electric field produces a force on other charges in its ___.
3. Heat energy is ___ of the potential and kinetic energy of the particles in a substance.
4. In ___, energy is released when atoms are combined or fused together.
5. When heat flows into a substance it may ___ the kinetic energy of the particles and thus elevates its temperature.
IV. Arrange the following words in pairs according to similar meaning and translate them:
Motion, profound, instrument, to operate, to contain, to emit, to occur, for example, to proceed, to reduce, to radiate, for instance, movement, device, deep, to include.
V. Use the words underlined in this text to fill the gaps in the following sentences (given below):
Electricity is the phenomenon associated with positively and negatively charged particles of matter at rest and in motion, individually or in great numbers. Since every atom contains both positively and negatively charged particles, electricity is connected with the physical properties and structure of matter and is an important factor in physics, chemistry and biology.
1. Lightning is a naturally occurring electrical _____.
2. Electrical conductivity is an important ______of metals.
3. Atoms, which were once thought to be the smallest _____, are known to consist of even smaller ones.
4. _____, atoms have only a weak charge, but a very large number together can make a powerful charge.
5. Albert Einstein discovered the relationship between ______ and energy.
VI. Themes for the presentation. You can do it in groups, in pairs or individually.
1. Electricityis a basic part of nature and it is one of our most widely used forms of energy.
2. The application of forms of energy.
3.How to produce and use electricity.
4. Renewable sources of energy.
Electrical phenomena have been studied since antiquity; though progress in theoretical understanding remained slow until the seventeenth and eighteenth centuries. Even then, practical applications for electricity were few, and it would not be until the late nineteenth century that engineers were able to put it to industrial and residential use. The rapid expansion in electrical technology at this time transformed industry and society. Electricity's extraordinary versatility means it can be put to an almost limitless set of applications which include transport, heating, lighting, communications, and computation. Electrical power is now the backbone of modern industrial society.
ELECTRIC CURRENT
I. Words and expressions for the text comprehension:
a flow
to flow ,
electric charge
voltage
across
to measure
the rate
to cause
a resistance
a feature
to determine
relationships
constant
direct current
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alternating current
pulsating current
to obtain
rectifier
entire
inductance
II. Translate the following adjectives and past participles with the negative prefix UN and define the root of the word:
Model: un questionable , ; questionable .
Unacceptable, unaccountable, unanalyzable, unbalanced, unbelievable, unbroken, uncaused, uncommon, unconnected, undeceded, unprovided, unvarying.
III. Read and translate the following text:
ELECTRIC CURRENT
The movement of electric charge is known as an electric current, the intensity of which is usually measured in amperes. Current can consist of any moving charged particles; most commonly these are electrons, but any charge in motion constitutes a current.
By historical convention, a positive current is defined as having the same direction of flow as any positive charge it contains, or to flow from the most positive part of a circuit to the most negative part. Current defined in this manner is called conventional current. The motion of negatively charged electrons around an electric circuit, one of the most familiar forms of current, is thus deemed positive in the opposite direction to that of the electrons. However, depending on the conditions, an electric current can consist of a flow of charged particles in either direction or even in both directions at once. The positive-to-negative convention is widely used to simplify this situation.
The process by which electric current passes through a material is termed electrical conduction, and its nature varies with that of the charged particles and the material through which they are travelling. Examples of electric currents include metallic conduction, where electrons flow through a conductor such as metal, and electrolysis, where ions (charged atoms) flow through liquids, or through plasmas such as electrical sparks. While the particles themselves can move quite slowly, sometimes with an average drift velocity only fractions of a millimeter per second, the electric field that drives them itself propagates at close to the speed of light, enabling electrical signals to pass rapidly along wires.
Current causes several observable effects, which historically were the means of recognizing its presence. That water could be decomposed by the current from a voltaic pile was discovered by Nicholson and Carlisle in 1800, a process now known as electrolysis. Their work was greatly expanded upon by Michael Faraday in 1833. Current through a resistance causes localized heating, an effect James Prescott Joule studied mathematically in 1840.
In engineering or household applications, current is often described as being either direct current (DC) or alternating current (AC). These terms refer to how the current varies in time.
Direct current, as produced by example from a battery and required by most electronic devices, is a unidirectional flow from the positive part of a circuit to the negative. If, as is most common, this flow is carried by electrons, they will be travelling in the opposite direction.
Alternating current is any current that reverses direction repeatedly; almost always this takes the form of a sine wave. Alternating current thus pulses back and forth within a conductor without the charge moving any net distance over time. The time-averaged value of an alternating current is zero, but it delivers energy in first one direction, and then the reverse. Alternating current is affected by electrical properties that are not observed under steady state direct current, such as inductance and capacitance. These properties however can become important when circuitry is subjected to transients, such as when first energized.
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I. Answer the questions:
1. What is an electric current?
2. What is an electrical conduction?
3. What does include an electric current?
4. What effects can cause current?
5. Give the definitions of direct current, alternating current.
II. Give English equivalents of the followings:
, , , , , , // , 㳿, , , , , , , , , , , , .
III. Give English equivalents of the followings:
To take place, direction, the circuit sections, at fixed intervals of time, the strength of the current, entire circuit, with the help of rectifiers, galvanic elements, a constant resistance, Ohm's law, to pass through, a unit of resistance, at the rate of.
IV. Tell what sentences are true and what are false:
1. The current which flows along wires consists of moving electrons.
2. We know the electron to be a minute particle having a negative electric charge.
3. The electric current can flow through solids, liquids and even through gases.
4. Melted metals change greatly when the current passes through them.
5. When the electrons flow in one direction only, the current is known to be a.c.
V. Fill in the gaps with the words given below:
