Electricity - Section 1 Flashcards
What is static electricity?
A stationary electric charge built up on an insulating material
What are the three laws of electrical charges?
Opposite charges attract
Like charges repel
Charged objects can be attracted to neutral objects
What is a Van de Graaff Generator?
A machine that uses friction to produce a build up of static electricity
For an electrical current to flow continuously, what two requirements must be met?
There must be an energy source
It must have a complete path or circuit for the charged particles to flow through
What are conductors?
Materials which electricity can flow through easily
What is an insulator?
This is a material that electrical current does not flow through easily
Insulating materials are often used as a protective cover on the conductor
What is circuit?
A path that controls the flow of electricity
What does a circuit usually include?
A conductor
An energy source
A device that converts the electrical energy to another form of energy (also called a load)
What is an ampere?
Unit used to measure the rate at which an electrical current flows
Abbreviated unit is A
What is an ammeter?
Measures electrical current in amperes, or milliAmps
What is voltage?
A measure of how much electrical energy each charged particle carries, in volts
What is a voltmeter?
Measured the charge in the potential energy of electrical charge compared to its potential energy
No volts or millivolts
What is resistance?
A measure of how difficult it is for electrons to flow through a substance
Measured in ohms
Symbol is the Greek letter Omega
What is an Ohmmeter?
Measures electrical resistance, in ohms
What are fuses?
Fuses contain a thin piece of special metal that will melt if the electricity going through it is too high. These must be replaced once that metal has melted
What are circuit breakers?
Have a special wire that heats up, but doesn’t melt. The hot wire triggers a spring that will turn off the switch with particular circuit or path. This can be switched back on once the wire has cooled
What is a cell?
A device that converts chemical energy into electrical energy
What are the two types of cells?
Dry cells
Wet cells
What are dry cells?
The chemicals in dry cells are in a paste
They are sealed so that they can be used in any position without the chemical leaking out
What are wet cells?
The chemicals in wet cells are liquid
The electrolyte is liquid, usually an acid
What are the advantages and disadvantages to set cells?
An advantage is that they are generally cheaper and easier to make
A disadvantage is that they can easily spill, and the acid is highly corrosive
What are primary cells?
These are cells that can only produce electricity until their chemicals have fully reacted
After this happens they must be thrown away
What are secondary cells?
These are rechargeable cells
Once the reactants have been used up, electricity can be run back through them using an external electrical source
What are batteries?
Two or more cells joined together to produce an electric current
What is electroplating?
When a cheap metal is used and then is “plated” with a more expensive metal
