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31 Cards in this Set
- Front
- Back
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Charge |
FD: A fundamental property of matter: For example, protons and electrons are positively and negatively charged, respectively. Neutrons, meanwhile, have no charge. Objects that have the same number of protons and electrons are "electrically neutral". Charges are measured in Coulombs. |
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Voltage |
Energy per charge |
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Electromotive force |
Energy per unit charge, given by a cell/battery, in driving the charges for one complete look around a circuit FD: This can be interpreted as "Voltage supplied" or "Voltage up" |
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Electrical potential difference (electrostatics) |
Work done per unit charge in moving a positive test charge from one point to another |
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Electrical potential difference (circuitry) |
Energy per charge dissipated at circuit component(s) FD: This can be interpreted as "Voltage down"
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Electrif field strength |
Force per unit charge acting on a positive test charge |
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Electrical potential energy |
Potential charge of a charge in a location that is affected by electric fields due to other charges FD: Electrical potential energy can be positive or negative. For reference, a charge that is infinitely distant from other charges will have a potential energy value of zero |
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Electron volt |
Energy required to move 1 electron across a potential difference of 1 Volt FD: 1 eV = 1.6 x 10-19C x 1J/C = 1.6 x 10-19J |
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Electric current |
Force per unit length (due to magnetic effects) between parallel current-carrying conductors FD: Current in circuitry is more often understood as rate of flow of charge |
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Resistance |
Ratio between voltage across a circuit component to current through the circuit component FD: Can be defined using R=V/I in words |
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Resistivity |
FD: An intrinsic property of conductors and insulators. Resistance = resistivity x length/cross-section area |
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Ohm's law |
Voltage is directly proportional to current when resistance is constant |
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Electrical power |
FD: Rate of conversion of electrical energy into other forms |
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Internal resistance |
FD: The resistance within the battery and the conducting wires |
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Terminal voltage |
The voltage available to the external circuit components after voltage dissipated due to internal resistance is considered. The equation V = E - Ir can be interpreted as "terminal voltage = electromotive force - voltage wasted due to internal resistance". |
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Ideal ammeter and voltmeter |
An idea ammeter is connected in series and has no resistance. An ideal voltmeter is connected in parallel and has infinite resistance |
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Potential divider |
A variable resistor, often with a sliding contact that allows a portion of the variable resistors to be parallel to a circuit component, and another portion to be in series with the same circuit component component. The potential divider allows circuit components to be totally turned off, or be subjected to the maximum available voltage |
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Light-dependent resistor |
A variable resistor whose resistance decreases as light intensity increases |
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Negative temperature coefficient (NTC) thermistor |
A variable resistor whose resistance decreases as temperature increases |
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Strain gauge |
A variable resistor whose resistance increases as the tension on the piece of conductive material increases (as tension causes a wire to become thinner and narrower) |
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Newton's universal law of gravitation |
The mutual gravitational force between two objects is proportional to each mass, and is inversely proportional to the square of the separation |
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Point mass |
An assumption that all the mass of a large stellar object is concentrated at th ecentre of mass |
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Gravitational field strength |
Force per unit mass acting on a point mass |
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Test charge |
A small charge that has no influence in the surrounding electrical field pattern |
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Conductor |
A material which has free electrons that will undergo net movement when a potential difference is applied across it. FD: For a conductor that is not conducting, all the free charges are located at the surface, and the field inside = 0 |
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Insulator |
A material which does not possess free electrons FD: Insulators can be changed by friction - rubbing off or adding surface electrons using mechanical means |
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Coulomb's law |
The mutual electrostatic force between two charges is proportional to each charge, and is inversely proportional to the square of the separation. FD: Electrostatic forces can be attractive or repulsive. For comparison, gravitational forces are always attractive |
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Conservation of charge |
FD: The total amount charges are conserved in all processes, such as the transfer of charge between two conducting spheres, or current entering or leaving a junction within a circuit |
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Magnetic field |
Lines of forces, due to moving charges, acting on other moving charges FD: Magnetic field always points from North to South, except within the core of a solenoid |
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Magnetic flux |
The product of the normal component of the magnetic field and the area that it is influencing |
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Magnetic field strength |
The strength of a magnetic field due to a straight current-carrying wire or a solenoid FD: Also referred to as "magnetic flux density" |
