Which formula expresses the period in terms of frequency?

Which formula expresses the period in terms of frequency?

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

Answer: (A)

Period is the time required for one complete cycle, while frequency is how many cycles happen each second. Because more cycles per second means a shorter time per cycle, they are reciprocal. That gives the relation T × f = 1, so the period is T = 1/f. For example, a 60 Hz signal has a period of 1/60 second ≈ 0.0167 s. This also means f = 1/T. The other expressions don’t fit: T = f would mix seconds and cycles without the reciprocal, T = f^2 would pair frequency with a square unit, and T = f/1 is just f, which is not the period.

Period is the time required for one complete cycle, while frequency is how many cycles happen each second. Because more cycles per second means a shorter time per cycle, they are reciprocal. That gives the relation T × f = 1, so the period is T = 1/f. For example, a 60 Hz signal has a period of 1/60 second ≈ 0.0167 s. This also means f = 1/T. The other expressions don’t fit: T = f would mix seconds and cycles without the reciprocal, T = f^2 would pair frequency with a square unit, and T = f/1 is just f, which is not the period.