Physics Glossary (WEP\'S) PDF

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Physics Glossary (WEP’S)

Electric Current: Is a flow of charge due to the passage of charged particles Conventional Current: Charge carriers are electrons in a metallic conductor, which flow from negative to positive. Early experiments with electricity did not know the electron existed and arbitrarily defined current as a flow of positive charge.

Coulomb: Unit of electricity equal to the charge flow in 1 second when the current flowing is 1 ampere.

Mean Drift Velocity: Average speed charge carriers move through a material in a certain direction.

Insulator: Doesn’t conduct electricity, has no charge carriers free to move. Electromotive force: The electrical energy transferred per unit charge when one other type of energy is converted into electrical energy.

Internal resistance: Is the loss of potential difference per unit current in the source, when current passes through the source (resistance inside a source of electrical energy due to the opposition of the flow of charge)

Charge carriers: Charged particles that move through a material when a P.D. is supplied across it

Ohm’s Law: The P.D. across a metallic conductor is proportional to the current through it provided the physical conditions do not change.

Thermistor: A resistor which is designed to have a resistance that changes with temperature (usually decreases as temperature increases)

P.D: Is energy per unit charge converted from electrical energy into other forms (work done) Kirchoff’s First Law: At any junction in a circuit, the total current leaving the junction is equal to the total current entering the junction.

Kirchoff’s Second Law: For any complete loop of a circuit, the sum of e.m.f.s around the loop is equal to the sum of potential drops around the loop.

Voltage: P.D. between any two points in a circuit is defined as: the energy transfer per coulomb of charge that flows from one point to another.

Difference between P.D. and E.M.F: Voltage is energy transfer (work done) per unit charge in the load (or connected devices) in a circuit / EMF is energy transfer per unit charge in the battery or power supply.

Kilowatt-Hour: A unit of energy equal to a power of 1000 W consumed over the period of 3600 seconds.

Ramshaw

Resistivity: Resistance per unit length (x) area of cross-section… (Property of a material) Resistance: Potential difference (/) current... (Property of an object, taking dimensions into account)

EMF: of a source of electricity is defined as the electrical energy per unit charge produced inside the source.

Ampere: is defined in terms of the force between 2 parallel wires when they pass the same current.

Potential Divider: Is the ratio of P.D’s across each resistor equal to the resistance ratio of the 2 resistors.

Ramshaw...