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Physics Ch. 19
Question | Answer |
---|---|
Define current. | The rate at which electric charges move through a given area. |
In common conductors current is due to... | The movement of electrons. |
Moving charges that make up a current can be what type of charge? | Positive, negative, or a combination of the two. |
Define an electrolyte. | A solute that consists of charge carriers. |
Gases and dissolved salts form... | Current from the movement of positive charges moving in one direction and negative charges moving in the other direction. |
Define drift velocity. | The net velocity of a charge carrier moving in an electric field. |
True or false: Electrons move quickly. | False, the move at 2.46x10^(-4) m/s. |
Give an example of electric current. | Turning on a light. |
Electric Field almost at the speed of light that sets what? | Electrons in motion. |
Define direct current. | Charges move only in one direction (light bulbs electronics). |
Define alternating current. | The motion of charges continuously changes in the forward and reverse directions (homes and electric motors). |
Define resistance. | The opposition to the flow of current in a conductor. |
What's the SI unit for resistance? | Ohms. |
What causes less resistance? | -Short length. -Large cross sectional area. -Material (ex. copper). -Temperature (lower). |
What causes more resistance? | -Longer length. -Small cross sectional area. -Material (ex. aluminum). -Temperature (higher). |
Define a superconductor. | A material whose resistance is zero at or below some critical temperature, which varies with each material. |