Physics concepts Electricity 2

Volt

• The unit of electric current.

• The unit of potential difference (voltage). One volt is equal to one joule per coulomb.

• The unit of resistance in an electrical circuit.

• The unit of power in an electrical circuit.

Ohm’s Law

• The current flowing through an Ohmic conductor at constant temperature is directly proportional to the potential difference (voltage) across it.

• The resistance of an Ohmic conductor is inversely proportional to the current flowing through it.

• The voltage across an Ohmic conductor is independent of the current flowing through it.

• The current flowing through a conductor is always constant regardless of the voltage applied.

Potential Difference

• The energy that is transferred per unit charge between two points in a circuit.

• The total resistance in a circuit.

• The amount of current flowing through a conductor.

• The voltage drop across a single resistor.

Power

• The amount of energy consumed by an appliance over time.

• The rate at which an appliance transfers energy. For a circuit component, it is equal to the product of the current passing through it and the potential difference across it.

• The total energy stored in a circuit component.

• The measure of how quickly an appliance can be turned on or off.

Resistance

• A measure of the opposition to current flow.

• A type of electrical charge.

• The speed of electrons in a conductor.

• The total energy consumed by a circuit.

Parallel

• Components connected in parallel have the same potential difference (voltage) across each component.

• Components connected in series have the same potential difference (voltage) across each component.

• The total current in a parallel circuit is equal to the current through the largest component.

• In a parallel circuit, the voltage is divided among the components.

Ohm

• The unit of resistance.

• The unit of voltage.

• The unit of current.

• The unit of power.

Neutral Wire

• The blue coloured wire that completes the circuit in a mains power supply.

• The red coloured wire that carries current to the appliance.

• The green coloured wire used for grounding.

• The yellow coloured wire that indicates a live connection.

Voltmeter

• A device that measures current in a circuit.

• A device that is connected in series with a component to measure the resistance across it.

• A device that is connected in parallel with a component to measure the potential difference (voltage) across it.

• A device that converts electrical energy into mechanical energy.

Mains Electricity

• An a.c supply with a frequency of 60Hz and a value of 120V.

• An a.c supply with a frequency of 50Hz and a value of 230V.

• A d.c supply with a frequency of 50Hz and a value of 230V.

• An a.c supply with a frequency of 50Hz and a value of 110V.