The flow of charge through a conductor is called electric current. A conventional current flows from the positively charged body to the negatively charged body. Electronic current flows fro the negatively charged body to the positively charged body.
A cell is a device in which potential difference is maintained between its two terminals by the conversion of chemical energy into electrical energy.
Simple Volatic Cell
This cell was invented by Alessandro Volta in the year 1800. it was the first device which could create a constant potential difference with the help of chemical energy.
Button cells are as small as buttons. They are commonly emplyed in small electronic devices, such as quartz wrist watches, calculaters etc.
The path along which electric current flows is called electric circuit.
Materials which allows the electric current to flow through them are called electric conductors eg: all metals are conductors of electricity. Non-metals like graphite and gas carbon are also coanductos of electricity
Materials which do not allow current to flow through them are called electric insulators eg: rubber, plastics etc.
The branch of physics which deals with the relationship between electricity and magnetism is called as electromagnetism.
When a magnetic field is changed near conductor, a current is produced in it. This was discovered by Farady in 1931.
Phenomenon due to which a changing magnetic field within a closed coil induces an electric current in the coil is called as electromagnetic induction.
Current produced in a closed coil when the magnetic lines of force rapidly change within it is called induced current. This principle is used in generating electric current by electric generator. Magnitude of the current depends upon:
- Strength of inducing magnet.
- Number of turns in coil
- Relative motion of magnet with respt to coil.