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8 Cards in this Set
- Front
- Back
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alternating current (AC). |
When current keeps reversing direction, it is called alternating current (AC). The current that runs through the wires in your home is alternating current. |
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direct current (DC)
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When current flows in just one direction, it is called direct current (DC). The current that flows through a battery-powered flashlight is direct current. |
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electric conductors |
Materials that have low resistance to electric current are called electric conductors. Many metals—including copper, aluminum, and steel—are good conductors of electricity. Water that has even a tiny amount of impurities in it is an electric conductor as well. |
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electric insulators. |
Materials that have high resistance to electric current are called electric insulators. Wood, rubber, and plastic are examples of electric insulators. Dry air is also an electric insulator. |
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Electric current |
Electric current is a continuous flow of electric charges. Current is measured as the amount of charge that flows past a given point in a certain amount of time. The SI unit for electric current is the ampere (A), or amp. Electric current may flow in just one direction, or it may keep reversing direction. |
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voltage |
Voltage is measured in an SI unit called the volt (V). For example, the terminals of the car battery in Figurebelow have a potential difference of 12 volts. This difference in voltage results in a spontaneous flow of charges, or electric current. |
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Ohm’s law |
You may have a better understanding of Ohm’s law if you compare current flowing through a wire from a battery to water flowing through a garden hose from a tap. Increasing voltage is like opening the tap wider. When the tap is opened wider, more water flows through the hose. This is like an increase in current. Stepping on the hose makes it harder for the water to pass through. This is like increasing resistance, which causes less current to flow through a material. Still not sure about the relationship among voltage, current, and resistance? |
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resistance |
which causes less current to flow through a material. Still not sure about the relationship among voltage, current, and resistance? |
