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Science ch.7
Question | Answer |
---|---|
charging by contact | process of transferring charge between objects by touching or rubbing |
charging by induction | process of transferring charge between objects by bringing a charged object by a neutral object |
circuit | CLOSED conducting loop through which an electric current can flow |
conductor | material such as copper wire through which an excess of electrons can move easily |
electric current | flow of electric charge through a wire or any conductor; measured in Amperes (A-amps) |
electrical power | rate at which electrical energy is converted to another form of energy; expressed in Watts (W) |
Insulator | material that does not allow electrons to move through easily |
Kilowatt-hour | unit of electrical energy which is 1000 watts of power used for one hour |
law of conservation of change | states that charge can be transferred from one object to another but cannot be created or dedstroyed |
ohm's law | states that the current in a circuit equals the voltage difference divided by the resistance |
resistance | tendency for a material to oppose electron flow and change electrical energy and light |
parallel circuit | a circuit in which electric current has more than one path to flow |
series circuit | circuit in which electric current has only one path to follow |
static electricity | electricity generated when 2 objects rub against each other and result in the accumulation of excess electric charges on an object |
voltage difference | push that causes electrical charges to flow through a conductor measured in volts (V) |
Be able to draw electric and parallel circuits | Be able to draw electric and parallel circuits |
Formula for calculating power | Power=current (times) voltage difference P=IV |
Formula for calculating energy | Energy=power (times) time E=PT |
protons have____ charges and electrons have _____ charges | positive; negative |
How do atoms become charged? | by gaining or loosing electrons |
What happens in most atoms? | the charges of the protons an electrons cancel each other out and the atom has no net charge |
opposite charges____ and like charges ____ | attract;repel |
what do electrons move easily through? | conductors such as metals |
what don't electrons move easily through? | insulators such as plastic, wood, rubber, and glass |
What is an example of charging by contact? | static electricity from your feet rubbing the carpet |
static discharge | a transfer of charge through the air between 2 objects because of a buildup of static electricity ex. lightning |
grounding | using a conductor to direct an electric charge into the ground |
How can you detect the presence of electric charges? | by using an electroscope |
how many loops does a series circuit have? | one ex. christmaslights |
What is possible with a parallel circuit? | individual parts can be turned off without affecting the entire circuit |
electric fuse | contains a small piece of metal that melts if the current becomes to high, opening the circuit and stopping the flow of electricity |
circuit breakers | contain a small piece of metal that bends when it gets to hot, opening the circuit and stopping the current |
What is electrical power expressed in? | Watts |