Period (physics)

smallest temporal unit after which a process repeats

A time period (denoted by 'T'' ) is the time taken for one complete cycle of vibration to pass a given point.[1] As the frequency of a wave increases, the time period of the wave decreases. The unit for time period is 'seconds'. Frequency and time period are in a reciprocal relationship that can be expressed mathematically as: T = 1/f or as: f = 1/T.

  • Orbital period is the time for something to go round (orbit) something else.
  • The period of a pendulum is the time it takes from one side to the other and back.
  • An electron moving in a helical orbit that has an axis at right angles to the magnetic field has a period given by T=2πm/qB, where m is the mass of the electron, q is the charge of the electron and B is the magnetic field in the region.


  1. Tongue, Benson, Principles of Vibration, Oxford University Pres, 2001, ISBN 0-195-142462