A new inexperience computer technician wants to know what brownouts are. What should you tell him?

A.
Brownouts is a very high voltage level-usually twice the normal voltage.

B.
Brownouts are a voltage increase (10 or 20 volts above normal) that occurs over a longer period of time, such as for one or two seconds.

C.
Brownouts occur over longer periods of time usually several seconds or longer.

D.
None of the above.

Explanation:
When the power supply drops below normal levels, sags and brownouts occur. Sags are short periods of time when the supply voltage is low. Brownouts occur over longer periods of time (several seconds or longer).
Incorrect Answers:
A: A spike is a very high voltage level-usually twice the normal voltage.
B: A surge is a voltage increase (10 or 20 volts above normal) that occurs over a longer period of time, such as for one or two seconds.
References:
Charles J. Brooks, Server+ Certification Exam Cram 2 (Exam SK0-002), QUE Publishing, Indianapolis, 2006, pp. 227-240.