Electricity Flashcards
What is an electric current?
An electric current is caused by the flow of electrons through a good conductor such as a metal.
A good insulator does not allow electric current to flow e.g. wool, air.
Definitions
An electric current is a flow of electric charge. Unit is Ampere.
Conductors are substances which allow electric current to flow through them freely.
Insulators are substances which do not allow electric current to flow through them.
Electrical energy
Electrical energy can be converted into light, heat, kinetic and sound.
Light energy so we can see in the dark.
Heat energy so we can cook + heat buildings.
Kinetic energy for electric motors.
Sound energy for music.
Closed circuits
A close circuit is needed for the current to flow.
If there is a break in a circuit then the current won’t flow and the electrical energy can’t get through
Batteries
Energy provided by a battery or power pack is needed to move the current around the circuit.
The battery pumps electrons from its negative end around a circuit.
The electrons travel all the way around and are attracted back to the positive end of the battery.
The negative end of the battery is an area of High Electrical Pressure.
The positive end of the battery is an area of Low Electrical Pressure.
Electrons will move from areas of High Electrical Pressure to areas of Low Electrical Pressure.
Potential Difference
The difference in electrical pressure between the positive and negative ends is called the Potential Difference. Whenever there is a potential difference electricity will flow.
This potential difference is known as Voltage and is measured in volts.
Resistance
Resistance is the opposition to the flow of electrons. The unit is the Ohm (Ω), and it is measured using an Ohmmeter.
If a Resistor is placed in an electric circuit, it will slow down the flow of electrons.
Ohm’s Law
Ohm’s law states that voltage is directly proportional to current
• V= voltage, I= current, R= resistance
