How To Hide The Page Extension

The problem is that i want to hide the php extension from the visitor so that no one knows what scripting language lies beneath..

If I use the following solution {

I think I should write snippets of php codes inside html files.. so i want apache to go through each html file to see if there are php code or not..

I write the following mime types with cpanel:

application/x-httpd-php .php .adp
application/x-httpd-php .php .htm
application/x-httpd-php .adp
}

Then {
Error appears when I go to any page in the site "Internat Server Error"
}

Else if {
I can use .htaccess to do the same effect in a particular directory
}

Then {
The same error appears "Internal Server Error"
}

Else {
What can I do?
}