Прочитайте текст и выполните задания. Electricity 1. Electricity is a flow of negative charges calle...: ответ на тест 884752 - Английский язык

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Electricity
1. Electricity is a flow of negative charges called electrons. These electric charges are measured in units called coulombs. Electricity is a very versatile form of energy that can be converted into many other forms of energy, including light and heat, direct current (DC), which flows in one direction only, and alternating current (AC), which changes direction 60 times per second.
2. An electric circuit is an unbroken conducting path from, and back to, a power supply. It has three main parts: the power supply, the conductor, and the load. The power is provided by a generator or battery, the conductor carries the current, and the load is an electric device such as a lamp.
3. Unlike current electricity, static electricity does not flow. It is created when an electrically neutral substance loses or gains electrons, making it, respectively, positively or negatively charged. You can create static electricity by rubbing a balloon on your clothing. Electrons will move from the clothing to the balloon, making the balloon negatively charged and the clothing positively charged. The resulting static electricity on each will attract small, light objects such as pieces of paper.
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Electricity
1. Electricity is a flow of negative charges called electrons. These electric charges are measured in units called coulombs. Electricity is a very versatile form of energy that can be converted into many other forms of energy, including light and heat, direct current (DC), which flows in one direction only, and alternating current (AC), which changes direction 60 times per second.
2. An electric circuit is an unbroken conducting path from, and back to, a power supply. It has three main parts: the power supply, the conductor, and the load. The power is provided by a generator or battery, the conductor carries the current, and the load is an electric device such as a lamp.
3. Unlike current electricity, static electricity does not flow. It is created when an electrically neutral substance loses or gains electrons, making it, respectively, positively or negatively charged. You can create static electricity by rubbing a balloon on your clothing. Electrons will move from the clothing to the balloon, making the balloon negatively charged and the clothing positively charged. The resulting static electricity on each will attract small, light objects such as pieces of paper.
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Electromagnetism
1. Electricity and magnetism combine to form one of the fundamental forces of the universe – electromagnetism. The two constantly interact, and the relationship between them is one of the most important in physics. For example, an electric current passing through a wire creates a magnetic field; and if the lines of force around a magnet are cut by a passing object, an electric current will be produced.
2. Magnets are attracted to iron and to any material that contains iron. Magnets have two poles, a north pole and a south pole. Unmagnetized iron and steel have magnetic regions of atoms called domains that are jumbled up and point in lots of different directions. When iron or steel becomes magnetized, the domains become aligned and they all point in the same direction. One end of each domain points toward the magnetic north pole.
3. Electronics is a new branch of physics, and one that plays an increasingly important part in our lives. It is concerned with the use of electricity to produce signals that carry information and control devices such as computers. These devices contain electric circuits through which electric current flows. The controlling parts in a circuit are called components, and these include diodes and transistors. Components can amplify currents, switch them on and off, or change their direction.
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Light
1. The form of energy that illuminates our world is called light. It usually comes from hot objects, like the sun or fire, but it is also produced by electricity and some chemical reactions. Light is the only part of the electromagnetic spectrum (which includes microwaves, ultraviolet rays, and X-rays) that is invisible to the human eye. It travels at 186,000 miles (300,000 km) per second, and nothing can travel faster. Like other forms of energy, light travels in waves, but it can also travel in packets of energy called quanta. This enables it to travel through a vacuum.
2. Light rays are reflected when they hit a shiny or silvered surface, such as a still pool of water or a mirror. Reflection involves two light rays: the incoming ray and the reflected ray which bounces off the reflecting surface. The two rays are at identical angles to the reflecting surface on either side of an imaginary line.
3. Refraction is a property of all types of energy that travel in waves, including light. Light waves normally travel in straight lines, but when they pass from one transparent material to another, they usually refract, or bend. Refraction occurs because light travels at different speeds in different materials. As light from a material with a low density, such as air, enters a material with a high density, such as water, its speed is reduced. This causes it to bend (except when it enters a material at a right angle).
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Technology
1. Technology is the usage and knowledge of tools, techniques, crafts, systems or methods of organization in order to solve a problem or create an artistic perspective. Technologies significantly affect human as well as other animal species' ability to control and adapt to their natural environments. The human species' use of technology began with the conversion of natural resources into simple tools.
2. The prehistorical discovery of the ability to control fire increased the available sources of food and the invention of the wheel helped humans in travelling in and controlling their environment. Recent technological developments, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. However, not all technology has been used for peaceful purposes; the development of weapons of ever-increasing destructive power has progressed throughout history, from clubs to nuclear weapons.
3. Technology has affected society and its surroundings in a number of ways. In many societies, technology has helped develop more advanced economies (including today's global economy) and has allowed the rise of a leisure class. Many technological processes produce unwanted by-products, known as pollution, and deplete natural resources, to the detriment of the Earth and its environment. Various implementations of technology influence the values of a society and new technology often raises new ethical questions.
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Solid
1. Solid is one of the major states of matter. It is characterized by structural rigidity and resistance to changes of shape or volume. Unlike a liquid, a solid object does not flow to take on the shape of its container, nor does it expand to fill the entire volume available to it like a gas does. The atoms in a solid are tightly bound to each other, either in a regular geometric lattice or irregularly one.
2. The branch of physics that deals with solids is called solid-state physics, and is the main branch of condensed matter physics (which also includes liquids). Materials science is primarily concerned with the physical and chemical properties of solids. Solid-state chemistry is especially concerned with the synthesis of novel materials, as well as the science of identification and chemical composition.
3. The forces between the atoms in a solid can take a variety of forms. For example, a crystal of sodium chloride (common salt) is made up of ionic sodium and chlorine, which are held together by ionic bonds. In diamond or silicon, the atoms share electrons and form covalent bonds. In metals, electrons are shared in metallic bonding. Some solids, particularly most organic compounds, are held together with van der Waals forces resulting from the polarization of the electronic charge cloud on each molecule. The dissimilarities between the types of a solid result from the differences between their bonding.
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