File extensions

 1.What is a file extension?
a file extension is a suffix given to a file to indicate file format .

2.Main aspects of file extensions?

• Extensions are the way information is encoded.
• They are used according to file types.
• Different programs use different extensions.
• There are tons of extensions right know.
• Computers manage files according to their file extension.
• File extensions keep growing.
• File extensions are propietary (someone owns them and public.
• Usually the last three characters following a dot are the extension.
• Extensions can be hidden to spoof people.
• There are multiple extensions for text files in uncommon languages.

  3.How a file extension is related with digital information?
File extension is directly related to digital information because they determine the way digits (1´s and 0´s)
are arranged. Also they vary according to the file type and computers handle files different if they are in another format. 

4.What means encoding a text file with ANSI or
Unicode?

An ANSI text file only contains 256 characters so it doesn´t have on its table every character for every language but ANSI2(Double Byte) uses two bytes where the first one contains wich table should be used and the second which character is so multiple tables are used while Unicode uses 2 bytes for each character so  there are 65536 codes to be used and that  provides enough character codes to represent every character of most used languages around the world.

5.Most popular file extensions for word documents, images and sound. 

Audio: Mp3,AAC, Midi,WMA,ALAC,FLAC,Audible

Video:H.264,MP4,ASF,WMV,DivX,Xvid.

Images:JPG,RAW,PNG,GIF,BMP,TIFF,Exif,

Documents:XML,DOC,PDF,RTC,ODT,HTML,DjVu.