Alternating current or AC electricity is different from the DC electricity you get from batteries, in that it moves back and forth instead of flowing directly through the wire. AC is the electricity we have in our homes, which powers our television, lights and computers. Alternating Current or AC electricity is the back-and-forth movement of electrons in a wire, similar to a back-and-forth sloshing of water in a hose. When the force of a negative (-) charge is at one end of a wire and a positive (+) potential is at the other end, the electrons in the wire will move away from the (-) charge, just like in DC electricity. But if the charges at the ends of the wires are suddenly switched, the electrons will reverse their direction.

HTML is the lingua franca for publishing hypertext on the World Wide Web. It is a non-proprietary format based upon SGML, and can be created and processed by a wide range of tools, from simple plain text editors - you type it in from scratch- to sophisticated WYSIWYG authoring tools. HTML uses tags such as

and

to structure text into headings, paragraphs, lists, hypertext links etc.

HTML was originally developed by Tim Berners-Lee while at CERN, and popularized by the Mosaic browser developed at NCSA. During the course of the 1990s it has blossomed with the explosive growth of the Web. During this time, HTML has been extended in a number of ways. The Web depends on Web page authors and vendors sharing the same conventions for HTML. This has motivated joint work on specifications for HTML.

A system for providing continued telecommunications service in the event that a primary transmission route fails catastrophically.

A compact disc is a small, portable, round medium made of molded polymer (close in size to the floppy disk) for electronically recording, storing, and playing back audio, video, text, and other information in digital form.