At this time, False.
In most cases "xls".
PHP files extension is .php
The most common .dat files are video files from a video cd. Try playing with media player. See this also http://filext.com/file-extension/dat
.PTX is the extension for files created by E-Transcript. You can download the viewer of these files at http:/www.reallegal.com/softwareDownloadETranscriptViewer.aspIt is also used by Pentax cameras, but the most unusual and difficult to find is the one I gave.
The sys file extension was developed by Microsoft. Most files that end with sys are system data files and are not meant to be viewed by the users.
Files with the .bat extension are most likely to contain malicious code.
They do provide it, If your answering that for computing and collagecareersthe answer is false.
.src is mostly an arbitrarily used extension which in most cases aren't associated with any specific program. Mostly it stands for "Source code" of "some" kind Try opening it in Textpad. In Windows:.src files in windows are usually executables. Most notably, screensavers in windows have a .src extension. This is just a renamed .exe file. Caution: many viruses are transported in .src files because of the relative obscurity of the file extension. Because they are just .exe files, they can be represented by any icon the developer chooses, including those icons that look harmless (eg. text document icon).
.txt is the usual extension used with text files. There is also .rtf (rich text format) and .html (hypertext markup language) which are stored in plain text format, although they are not specifically text files.
the Microsoft word files are called document
Zipping a folder means to compress the files in the folder so that the take less space on a disk or can be sent in less time over the Internet. Folders and files so compressed will have the extension .zip. With most operating systems they can be uncompressed by double clicking them.
There is no answer for this, because it is the wrong question. A files extension doesn't matter to the file, it only exists so that the Operating System (OS) knows what application to open the file with. Technically you can have a text file with no extension if you don't mind telling Windows what program to use to open the file every time. Generally speaking .txt is the most common choice though.