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- Benjamin Franklin recognized that there aare two opposite types of electric charge and named them positive and negative.
- A simple rule to decide the interaction bbetween two separate charges is - like charges repel, unlike charges attract.
- - There are three types of particles found in atoms.
- ) The proton carries the positive charge
- ) The electron carries the negative charge
- ) The neutron is neutral (uncharged).
- Each atom has a nucleus consisting of prootons and neutrons.
- The electrons are some distance away fromm the nucleus, and are held loosely to the atom. Atoms are largely empty space.
- An ion is an atom which carries an excesss charge.
- A positive ion is an atom or molecule thaat has lost one or more of its electrons, leaving it with a net positive charge.
- A negative ion is an atom or molecule thaat has gained one or more electrons, leaving it with a net negative charge.
- The principle of conservation of charge sstates: The net electric charge in an isolated system remains constant.
- Robert Millikan discovered that an electrric charge could be quantized into a fundamental unit "e" which was later determined to be 1.602 x 10-19 Coulombs.
- The Coulomb is the SI unit of electric chharge
- Most materials can be categorized as condductors or insulators.
- Insulators greatly restrict the flowing oof electrons through the material. Examples are glass, rubber, wood and plastics.
- Conductors permit the flowing of electronns through the material. examples are metals, many liquids, and plasmas.
- Semiconductors are intermediate in their ability to conduct charge.
- A superconductor is a conductor, which att low temperatures, permits currents to pass unimpeded through the material.
- Positive and negative charges can be sepaarated by rubbing two objects together.
- Both insulators and conductors can becomee charged by contact.
- Conductors can be charged by induction, wwhich is a process that causes charges to separate without touching the object.
- A surface charge can be induced on an inssulator by polarization, which results in more positive charge on one side of a molecule than on the other side.
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