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

Define resistance

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.

Define power

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?

zero resistance

What is the ideal resistance of an ideal voltmeter?

infinite resistance

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.

Define thermistor

A resistor whose resistance falls when its temperature rises.