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23 Cards in this Set
- Front
- Back
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Charging by contact |
When two objects touch and electrons are transferred |
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Charging by induction |
Electrons moved when a charged object is brought near a conducting surface |
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Charge Polarization |
Charge is separated with a negative area and positive area Static Cling is a result of polarization |
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Van de Graaf Generator
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Used to generate static charge
Charges by induction High voltage low current |
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Electric Fields
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The field around a charge
Have both magnitude and direction. magnitude is calculated by Coulomb's Law Equation Direction is the direction of the electrical force on a small positive that charge |
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Electric Field Lines
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the closer together the lines are the stronger the field Lines of electric force point away from positive and towards negative charges Lines of force never intersect, they either merge to form one line or bend away from each other |
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Electric Shielding
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Electrons are mutually repulsive they will spread evenly over the outer surface of a metal object
shielding can occur in spherical objects due to symmetry Gravity cannot be because there is no repulsive element. |
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Electric Potential Energy |
A charged object has PE due to its location in an electric field Work required to push an object against an electrical field = to the amount of work done to move or separate charges |
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Work |
Transfer of energy |
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Electric current |
Flow of Electrons Flows when there is a potential difference between two sides of a conductor Flows from high to low potential energy To maintain flow the potential difference must be maintained Static shocks occur when the potential difference is quickly balanced |
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Amperes |
measures Electric Current 1 Coulomb of charge per second =1A Measures the actual number of electrons that pass through a circuit per unit of time Rate of electron flow Lower amperage= the fewer electrons pass a point in the wire per second A=C/t |
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Electrical Resistance |
Ability to impede the flow of charge |
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Conductivity |
Measure of how easily charge can flow through a material |
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Factors that Determine Resistance of a Conductor |
1) Composition of the wire (what elements of mix of elements) 2) Length of wire (direct proportion) 3) Diameter of wire (inverse proportion) d-increase R-decrease 4) Temp of wire Temp increase Resist increase |
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Voltage Sources |
Potential difference is measured in volts Potential difference is provided by a voltage source For generators voltage provides the pressure or force to move electrons through a circuit. |
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Ohm's Law |
Measure of Electrical Resistance Voltage= Current * Resistance V=I*R Current is inversely proportional to resistance Current is proportional to voltage |
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Electric Power |
1kW-h=3.6*10^6 J |
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Electric Shock |
Body's resistance 100-500,000 Ohms |
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Direct Current |
Charge always flows in the same direction |
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Alternating Current |
Charge changes direction |
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Hertz |
Cycles per second Hz |
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Electron Motion |
Electrons ordinarily have a random motion Randomness cancels out motions resulting in no current flow Voltage gives order to the motion |
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Electric Power |
Rate at which electric energy is converted into another form Measured in Watts Power=Current * Voltage P=IV or P=I^2R |
