Wednesday, 25 September 2013


Electricity is a form of energy. Electricity is the flow of electrons. All matter is made up of atoms, and an atom has a center, called a nucleus. The nucleus contains positively charged particles called protons and uncharged particles called neutrons. The nucleus of an atom is surrounded by negatively charged particles called electrons. The negative charge of an electron is equal to the positive charge of a proton, and the number of electrons in an atom is usually equal to the number of protons. When the balancing force between protons and electrons is upset by an outside force, an atom may gain or lose an electron. When electrons are "lost" from an atom, the free movement of these electrons constitutes an electric current.
Humans have an intimate relationship with electricity, to the point that it's virtually impossible to separate your life from it. Sure, you can flee from the world of crisscrossing power lines and live your life completely off the grid, but even at the loneliest corners of the world, electricity exists. If it's not lighting up the storm clouds overhead or crackling in a static spark at your fingertips, then it's moving through the human nervous system, animating the brain's will in every flourish, breath and unthinking heartbeat.

An electric generator is a device for converting mechanical energy into electrical energy. The process is based on the relationship between magnetism and electricity. When a wire or any other electrically conductive material moves across a magnetic field, an electric current occurs in the wire. The large generators used by the electric utility industry have a stationary conductor. A magnet attached to the end of a rotating shaft is positioned inside a stationary conducting ring that is wrapped with a long, continuous piece of wire. When the magnet rotates, it induces a small electric current in each section of wire as it passes. Each section of wire constitutes a small, separate electric conductor. All the small currents of individual sections add up to one current of considerable size. This current is what is used for electric power.
Geothermal power comes from heat energy buried beneath the surface of the earth. In some areas of the country, magma (molten matter under the earth's crust) flows close enough to the surface of the earth to heat underground water into steam, which can be tapped for use at steam-turbine plants. This energy source generates less than 1% of the electricity in the country.
Solar power is derived from the energy of the sun. However, the sun's energy is not available full-time and it is widely scattered. The processes used to produce electricity using the sun's energy have historically been more expensive than using conventional fossil fuels. Photovoltaic conversion generates electric power directly from the light of the sun in a photovoltaic (solar) cell. Solar-thermal electric generators use the radiant energy from the sun to produce steam to drive turbines. Less than 1% of the nation's electricity is based on solar power.
Wind power is derived from the conversion of the energy contained in wind into electricity. Wind power like the sun, is usually an expensive source of producing electricity, and is used for less than 1% of the nation's electricity. A wind turbine is similar to a typical wind mill.
Biomass(wood, municipal solid waste (garbage), and agricultural waste, such as corn cobs and wheat straw, are some other energy sources for producing electricity. These sources replace fossil fuels in the boiler. The combustion of wood and waste creates steam that is typically used in conventional steam-electric plants. Biomass accounts for less than 1% of the electricity generated in the United States.

Electricity is not made only of electrons. Charge actually comes in two varieties: positive and negative particles. Most people think the electrons are the electricity, and they think that protons are not electrical. Some text and reference books even state this outright, saying that electricity is composed of electrons. Nope. In reality the electrons and protons carry electrical charges of equal strength. If electrons are “electricity,” then protons are electricity too. Positive charge comes from having more protons than electrons; negative charge comes from having more electrons than protons.

It is generally believed that the protons within wires cannot flow, while the electrons can. Yes, this is true, but only for metals, and only for metals that are not liquid. Metals are composed of positively charged atoms immersed in a sea of movable electrons. When an electric current is created within a solid copper wire, the “electron sea” moves forward, but the protons within the positive atoms of copper do not. However, solid metals are not the only conductors, and in many other substances the positive atoms “do” move, and they “do” participate in the electrical current animation. These various non-electron conductors are nothing exotic. They are all around us. Two-way positive/negative electric currents can exist in: batteries, human bodies, all living organisms, the ground, the ocean, the sky (ionosphere), mercury and solder, ion-based smoke detectors, air cleaners, and the vertical “sky current” in the atmosphere, among others.

Electricity is measured in units of power called watts. It was named to honor James Watt, the inventor of the steam engine. One watt is a very small amount of power. It would require nearly 750 watts to equal one horsepower. A kilowatt represents 1,000 watts. A kilowatt-hour (kWh) is equal to the energy of 1,000 watts working for one hour. The amount of electricity a power plant generates or a customer uses over a period of time is measured in kilowatthours (kWh). Kilowatthours are determined by multiplying the number of kW's required by the number of hours of use. For example, if you use a 40-watt light bulb 5 hours a day, you have used 200 watts of power, or .2 kilowatthours of electrical energy.
What is meant by an ampere (amp)? Just as a current of water is measured in gallons per second, so we could measure an electric current in electrons per second. But the electron has such a tiny charge that enormous numbers of them are needed to make even a small current. For example, a pressure of one volt pumps 6.25 billion billion electrons per second through a resistance of 1ohm. A current of this size is known as an ampere. A current of a little less than 1 ampere flows through a common 100 watt light bulb. The total electric charge of 6.25 billion billion electrons is called onecoulomb (koo-lowm). An ampere is also defined as a current that carries a charge of one coulomb per second.


Electricity can be used to power all-electric vehicles and plug-in hybrid electric vehicles. These vehicles can draw electricity directly from the grid and other off-board electrical power sources and store it in batteries. Hybrid electric vehicles use electricity to boost fuel efficiency. Using electricity to power vehicles can have significant energy security and emissions benefits.

Shailesh kr shukla

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