Units




The SI derived unit of frequency is the hertz (Hz), named after the German physicist Heinrich Hertz. One hertz means that an event repeats once per second. If a TV has a refresh rate of 1 hertz the TV screen will change (or refresh) its picture once per second. A previous name for this unit was cycles per second (cps). The SI unit for the period is the second.

A traditional unit of measure used with rotating mechanical devices is revolutions per minute, abbreviated r/min or rpm. 60 rpm equals one hertz.

Comments

Post a Comment

Popular posts from this blog

Examples

Image
Light edit Visible light is an electromagnetic wave, consisting of oscillating electric and magnetic fields traveling through space. The frequency of the wave determines its color: 4 × 1014 Hz is red light, 8 × 1014 Hz is violet light, and between these (in the range 4- 8 × 1014 Hz ) are all the other colors of the visible spectrum. An electromagnetic wave can have a frequency less than 4 × 1014 Hz , but it will be invisible to the human eye; such waves are called infrared (IR) radiation. At even lower frequency, the wave is called a microwave, and at still lower frequencies it is called a radio wave. Likewise, an electromagnetic wave can have a frequency higher than 8 × 1014 Hz , but it will be invisible to the human eye; such waves are called ultraviolet (UV) radiation. Even higher-frequency waves are called X-rays, and higher still are gamma rays. All of these waves, from the lowest-frequency radio waves to the highest-frequency gamma rays, are fundamentally the same, and they are
Read more

Definitions

Image
For cyclical processes, such as rotation, oscillations, or waves, frequency is defined as a number of cycles per unit time. In physics and engineering disciplines, such as optics, acoustics, and radio, frequency is usually denoted by a Latin letter f or by the Greek letter ν {\displaystyle \nu } or ν (nu) (see e.g. Planck's formula). The relation between the frequency and the period, T {\displaystyle T} , of a repeating event or oscillation is given by f = 1 T . {\displaystyle f={\frac {1}{T}}.}
Read more