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51 Cards in this Set
- Front
- Back
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What is Static electricity |
the study of stationary charges |
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all objects contain {blank}. (in terms of charges) |
very large amounts of negative and positive charges. |
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are most objects balanced in charge? |
Yes |
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What do conductors do to the flow of charge. |
freely allow the charge to flow |
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What do insulators do to the flow of charge |
Impede the flow of charge |
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Opposite charges..... |
attract |
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Like charges..... |
repel |
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What is charging by contact |
When a charged object is brought into contact with another object. The charge will flow, until the charge density is equal. |
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What is charging by friction |
When 2 different objects are rubbed together charges can flow between them, charging both in opposite ways. |
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what is charging by Induction |
When a charged object us brought near a neutral object , like charges are repelled and opposite charges attracted including an apparent charge. |
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What are all the different forms of Conductivity? |
super conductor
good conductor poor conductor semi conductor insulator |
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What is a good conductor |
It has nearly no resistance to flow of charge |
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What is a super conductor |
no resistance to the flow of charge |
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what is a poor conductor |
sizeable resistance to the flow of charges |
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what is an insulator |
high resistance to the flow of charges |
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what is a semi conductor |
a material that can switch between being an insulator and a good conductor depending upon voltage. |
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Example of good conductors |
metals |
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examples of poor conductors: |
salt water, flesh, acids, humid air, silicates |
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examples of insulators |
rubber, fresh water, wood, cotton,salt, dry air |
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what is the groud |
a massive reservoir of excess charge |
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what is the ground used for |
safety and protection |
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what do most outlets have? |
a ground |
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what causes lightning |
friction between water molecules which causes a large imbalance of charge, and the negative charges concentrate and the bottom. |
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what is a lightning bolt between a cloud called? |
a sprit |
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what is a lightning rod? |
a conducting rod that is attached to a tall object and a long cable, covered in braided wire that runs deep underground. |
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what is current? |
rate at which charges move past a given point. |
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what is current defined by? |
I= Q/T ( i is current) (Q is charge) (t is time, measured in seconds) |
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what is currents measured in? |
amperes (A) |
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what is charge measured in? |
coulombs (C) |
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what is a circuit diagram? |
a simplified way of drawing an electrical circuit. |
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what is a load? |
a device that converts electrical potential into other forms of energy? |
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what is voltage/ potential difference? |
the amount of engird per unit charge in an electrical system. |
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voltage can be defined by: |
V= E/Q (Q is charge measured in coulombs, E is energy measured in joules) |
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What did Georg Simon Ohm measure? |
How current changes in a given load when the voltage supplied changes. |
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what does Ohm's law state? |
R= V/I (v is voltage measured in volts, I is current measured in amperes A, R is resistance measured in Ω) |
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what is resistance a measure of? |
How much an object impedes of electricity. |
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what are the 4 factors that determine the resistance of a wire. |
1)Material (some materials have higher resistance than others) 2) cross sectional area 3) length 4) temperature |
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what is power? |
power measures how quickly energy is delivered |
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what is power defined as? |
P=E/T (energy measured in joules, power is measured in watts) |
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how many joules does it take 1 watt for 1 second? |
1 joules |
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what is a series circuit? |
a circuit where the current must flow through each load in a sequence. |
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what is a parallel circuit? |
in a parallel circuit the current splits such that each charge only flows through one load. |
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what is Kirchoff's law? |
a node is a point in a circuit when the current splits |
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what is Kirchoff's current law? |
the total current flowing into a node is equal to the total current flowing out. |
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What is kirchoff's voltage law? |
in a closed loop all of the voltage supplied is used. |
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what can we replace all the resistors in a series or parallel circuit with? |
an equivalent resistor. |
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what is the equation for equivalent resistance in a series circuit? |
Req= R1= R2= R3 |
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what is a fuse? |
a fuse is a safety device to prevent to much current from flowing through a wire. |
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what does a fuse consist of? |
a fuse glass club that contains a copper wire that will melt if too much current flows through. |
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what does circuit breaker do? |
it breaks a circuit with too much current flowing through it, by means of a bimetallic strip. w |
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what is the equation for equivalent resistance in a parallel circuit?
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Req/1= 1/R1+1/R2+1/R3 |
