When you use Office 2013 on a personal computer, you must sign in with a Microsoft ________

When there is an abrupt change in the refractive index from the core to the cladding in fibers, this is:

A) Used for zero dispersion applications B) Due to the actual guided optical power C) Also called graded index D) Called step-index fiber

Which procedure is NOT a valid mechanism for performing account proofing when users are attempting to log into their account?

A. Have the user type in the username and password a second time. B. Send a text message to the user's phone. C. Ask the user three security questions based upon facts that only the user is likely to know. D. Have the user click a hyperlink in an email message.