Before you send a message to anyone, you should, of course, be sure that your recipient is likely to look for e-mail. Then you must know the recipient's internet address. With your Physics department account you can receive mail at the address
<username>@physics.utah.eduwhere <username> should be replaced by your user name without the angle brackets <>. The internet address structure is hierarchical, with domain names separated by a period. All US educational institutions have addresses ending with .edu. All internet addresses on the University of Utah campus end with .utah.edu. Commonly the first part of the address is the logical name of a single machine. However, the physics department has chosen to use a generic name physics to receive mail. The user name is separated from the machine designation with an sign.
It is not always necessary to use the full internet address to send mail. If you are sending mail to another user on the physics network, you may simply use the username, omitting physics.utah.edu. If you are sending to another machine on the campus network, it is sometimes possible to omit utah.edu.