Common types of electricity are static electricity, direct current (DC) electricity and alternating current (AC) electricity.
Static electricity is the collection of free electrons on the surface of a material, giving it a negative (−) charge. Atoms on the surface of another material that have lost one or more of their electrons are called positive (+) ions. 4____ Static electricity is caused by rubbing the two different materials together. Since opposite charges attract, there is a tendency for the electrons to attract toward the positive ions, resulting in static electricity.
In a metal or other conducting material, electrons will flow from an area of an excess negative (−) charges to an area of positive (+) charges. 5____ If the opposite charges are constant, such as with the terminals in a battery, the current is called direct current or DC electricity, because it is going in one direction. If the terminals constantly switch their polarity from (+) to (−) and back again, the direction of the electrons alternates and is called alternating current or AC electricity. 6 ____
DC can be created by a battery or DC generator. AC requires an AC generator for its creation. DC is used in many devices that do not require high voltages for their operation, such that batteries are used for power. AC can be used in higher voltages. 7 ____ AC is required for many electronic devices.
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