Define electric potential
the potential energy that each coulomb of positive charge would have if placed at that point in the field
Define electric potential difference
The work done per unit charge moving a positive test charge between two points in a circuit. measured in volts.
Define potential difference
the potential difference or p.d. is the energy transferred when one coulomb of charge passes from one point to the other point
Where does the potential difference act?
A potential difference acts across a component
What is the energy transfer equal to?
Energy transferred is equal to the amount of electric potential energy gained or to the amount of kinetic energy gained
Define the electonvolt
Unit of energy. The energy required to move one electron through a PD of one volt. W (eV) = q (electron charges) x V (volts)
1 eV = 1.6 x 10-19 J
Define electric current
The rate of flow of charge. Unit is the ampere. Conventional current flows from positive to negative
What is current?
The current is defined in terms of the force per unit length between parallel current-carrying conductors
The ratio of potential difference across a conductor to current through the conductor
State Ohm's Law
The current through a conductor is directly proportional to the voltage across its ends if the temperature and other conditions are constant
What is the difference between ohmic and non-ohmic behavior?
In ohmic behavior, the voltage is directly proportional to the current. While in the non-ohmic behavior voltage is not proportional to current.
The rate of converting energy. Unit is watt (W) = 1J/S
Define electromotive force
The total electrical energy given by the battery to each coulomb of charge OR the terminal potential difference of the source when no current flows
Define internal resistance
The resistance of the battery. Some of the energy provided by the source is converted to heat here and is not available in the external circuit components.
Define terminal potential difference
The potential difference measured across the terminals of the source which is less than the emf due to the internal resistance of the source.
How are resistors in a parallel circuit connected?
similar to a ladder
What is the potential difference across each resistor in parallel circuits?
The potential difference across each resistor in parallel is the same
What is the current in a parallel circuit?
The current in the main circuit is the sum of the currents in each of the parallel branches
How are the resistors connected in a series circuit?
similar to a chain
What is the current through each resistor in a series circuit?
The current through each resistor in the series is the same
What is the total potential difference across the resistors in a series circuit?
The total potential difference, V, across the resistors is the sum of the potential differences across the separate resistors
What is the combined resistance in a series circuit?
The combined resistance R in the circuit is the sum of the separate resistors
What is an ammeter and where does it connect?
Instrument which measures current in a circuit. It must be connected in series with the current it measures and has a very low resistance.
What is a voltmeter and where does it connect?
Instrument which measures potential difference in a circuit. It must be connected in parallel with the potential difference it measures and has a very high resistance.
What is the ideal resistance of an ideal ammeter?
What is the ideal resistance of an ideal voltmeter?
Define potential divider
The potential divider of a source is divided over two resistors in series in proportion to their resistances
Define electrical sensors
A component whose electrical properties (usually resistance) changes with its physical conditions.
A resistor whose resistance falls when its temperature rises.