Electricity Flashcards
Define Charge
The distribution of positive particles and negative particle on a surface.
Negatively charged, positively charged and neutrally charged.
Opposing charges attract each other whereas same charges repel
Define static electricity
Static electricity is the build up of an electric charge on a surface.
This build up commonly occurs because of one substance being rubbed against another surface.
Electrons (-) have been rubbed off one surface (charging it positive) and have transferred to the other surface (charging it negative)
Static electricity usually leaks away after some time into its surroundings, including the air around it, returning materials to their original neutral state.
Static electricity build up does not last forever and returns to neutral.
If charge continues to build up, electrons may jump across a gap from the negatively charged surface back to the positively charged surface, releasing all their energy in one go as they do so.
Define Current electricity
Current electricity is electricity from batteries and power points It is not static electricity.
It is made up of electrons moving along a wire and it is this movement of charge that is called an electric current.
These moving electrons have energy that is transformed into other forms of energy as the electrons pass through things like light globes (electrical energy - light), heating elements (- into heat), and motors (- movement).
If the electrons don’t move, no energy is received by the light globe or appliance, do nothing happens- it stays off.
Define Current
Current is a flow of electrical charge carriers, usually electrons or electron-deficient atoms. The common symbol for current is the uppercase letter I.
The standard unit is the ampere, symbolised by A. One ampere of current represents one coulomb of electrical charge.
Voltage itself does not go anywhere what moves through the electrical wire in a circuit is electrical current. It is a steady flow of electrons which is measured in amperes or amps.
Define resistance
The resistance in a wire increases as the length of the wire increases and the thickness of the wire decreases.
An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow and causes resistance.
The resistance of a long wire is greater that the resistance of a short wire because electrons collide with more ions as they pass through.
The resistance of a thin wire is greater than the resistance of a thick wire because a thin wire has fewer electrons to carry the current.
Define voltage
Voltage is a measure of the amount of energy supplied to the charges by the voltage source.
Voltage is a measure of the amount of energy used by the charges as they pass through a component.
Voltage is measured in volts (V) and can be measured using voltmeter. A transformer can be used to reduce voltage.
The voltage is a type of electrical force that makes electricity run through a wire and we measure this in volts. The greater the voltage more current will tend to flow. Volt in the electrical unit of voltage and it is represented by the symbol V.
