Search results
Results from the WOW.Com Content Network
In the physical sciences, the wavenumber (or wave number), also known as repetency, [1] is the spatial frequency of a wave, measured in cycles per unit distance (ordinary wavenumber) or radians per unit distance (angular wavenumber). [2][3][4] It is analogous to temporal frequency, which is defined as the number of wave cycles per unit time ...
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. [1] [a] The hertz is an SI derived unit whose formal expression in terms of SI base units is s −1, meaning that one hertz is one per second or the reciprocal of one second. [2]
1 Hz=1 s −1. The cycle per second is a once-common English name for the unit of frequency now known as the hertz (Hz). Cycles per second may be denoted by c.p.s., c/s, or, ambiguously, just "cycles" (Cyc., Cy., C, or c). The term comes from repetitive phenomena such as sound waves having a frequency measurable as a number of oscillations, or ...
The Planck constant, or Planck's constant, denoted by ,[1] is a fundamental physical constant [1] of foundational importance in quantum mechanics: a photon 's energy is equal to its frequency multiplied by the Planck constant, and the wavelength of a matter wave equals the Planck constant divided by the associated particle momentum.
Frequency is an important parameter used in science and engineering to specify the rate of oscillatory and vibratory phenomena, such as mechanical vibrations, audio signals (sound), radio waves, and light. For example, if a heart beats at a frequency of 120 times per minute (2 hertz), the period—the interval between beats—is half a second ...
SI base unit. s −1. The becquerel (/ ˌbɛkəˈrɛl /; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as an activity of one decay per second. For applications relating to human health this is a small quantity, [1] and SI multiples of the unit are commonly used. [2]
The electromagnetic wave equation is a second-order partial differential equation that describes the propagation of electromagnetic waves through a medium or in a vacuum. It is a three-dimensional form of the wave equation. The homogeneous form of the equation, written in terms of either the electric field E or the magnetic field B, takes the form:
The SI has special names for 22 of these coherent derived units (for example, hertz, the SI unit of measurement of frequency), but the rest merely reflect their derivation: for example, the square metre (m 2), the SI derived unit of area; and the kilogram per cubic metre (kg/m 3 or kg⋅m −3), the SI derived unit of density.