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In the case of electromagnetic radiation—such as light—in free space, the phase speed is the speed of light, about 3 × 10 8 m/s. Thus the wavelength of a 100 MHz electromagnetic (radio) wave is about: 3 × 10 8 m/s divided by 10 8 Hz = 3 m.
In 1890, Rydberg proposed on a formula describing the relation between the wavelengths in spectral lines of alkali metals. [2]: v1:376 He noticed that lines came in series and he found that he could simplify his calculations using the wavenumber (the number of waves occupying the unit length, equal to 1/λ, the inverse of the wavelength) as his unit of measurement.
Wavenumber has dimensions of reciprocal length, so its SI unit is the reciprocal of meters (m −1). In spectroscopy it is usual to give wavenumbers in cgs unit (i.e., reciprocal centimeters; cm −1 ); in this context, the wavenumber was formerly called the kayser , after Heinrich Kayser (some older scientific papers used this unit ...
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
x, s, d, u, x 1, s 1, d 1, u 1: m [L] Image distance x', s', d', v, x 2, s 2, d 2, v 2: m [L] Object height y, h, y 1, h 1: m [L] Image height y', h', H, y 2, h 2, H 2: m [L] Angle subtended by object θ, θ o, θ 1: rad dimensionless Angle subtended by image θ', θ i, θ 2: rad dimensionless Curvature radius of lens/mirror r, R: m [L] Focal ...
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
Dispersion of gravity waves on a fluid surface. Phase and group velocity divided by shallow-water phase velocity √ gh as a function of relative depth h / λ. Blue lines (A): phase velocity; Red lines (B): group velocity; Black dashed line (C): phase and group velocity √ gh valid in shallow water.
Lambda (written λ, in lowercase) is a non-SI unit of volume equal to 10 −9 m 3, 1 cubic millimetre (mm 3) or 1 microlitre (μL). Introduced by the BIPM in 1880, [ 1 ] the lambda has been used in chemistry [ 2 ] and in law for measuring volume, but its use is not recommended.