What is the formula used to determine frequency?

• A. f = T
• B. f = 1/T
• C. f = T^2
• D. f = 2T

Answer: (B)

Frequency tells you how many cycles happen each second, and it is the reciprocal of the period. The period T is the time for one complete cycle, so when cycles become shorter, more cycles fit into a second, making frequency larger. This relationship is written as f = 1/T. If T is in seconds, f will be in hertz (cycles per second). For example, a period of 0.02 seconds gives f = 1/0.02 = 50 Hz. The other forms don’t match how frequency and period relate: they would misstate the unit or the meaning of how often cycles occur.