Frequency, in physics, the number of waves that pass a fixed point in unit time. The number of cycles or vibrations undergone during one unit of time by a body in periodic motion. A body in periodic motion is said to have undergone one cycle or one vibration after passing through a series of events or positions and returning to its original state.

• Frequency Is usually denoted by f and the Greek letters nu (ν) and omega (ω).
• Nu is usually used for representing electromagnetic waves, such as light, X-rays, and gamma rays.
• Similarly Omega is used for representing angular frequency, Angular Frequency in other terms indicates how much an object rotates or revolves in radians per unit time.
• Hertz unit, named in honor of the 19th-century German physicist Heinrich Rudolf Hertz, is one of the most frequently used units for frequency. One hertz being equivalent to one cycle per second, Hertz is represented by Hz.
• Another unit of frequency is wave number which is often used in the field of spectroscopy.