Search results
Results From The WOW.Com Content Network
A commercial M 2 measurement instrument. There are several ways to define the width of a beam. When measuring the beam parameter product and M 2, one uses the D4σ or "second moment" width of the beam to determine both the radius of the beam's waist and the divergence in the far field.
The ratio of the BPP of an actual beam to that of an ideal Gaussian beam at the same wavelength is denoted M 2 ("M squared"). This parameter is a wavelength-independent measure of beam quality. The general wave equation, assuming paraxial approximation, yields:
The barn (b) is a unit of area used in nuclear physics equal to one hundred femtometres squared (100 fm 2 = 10 −28 m 2). The are (a) is a unit of area equal to 100 m 2. The decare (daa) is a unit of area equal to 1000 m 2. The hectare (ha) is a unit of area equal to 10 000 m 2 (0.01 km 2).
Comparison of 1 square metre with some Imperial and metric units of area. The square metre (international spelling as used by the International Bureau of Weights and Measures) or square meter (American spelling) is the unit of area in the International System of Units (SI) with symbol m 2. [1]
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.
A unit derived from the base units is used for expressing quantities of dimensions that can be derived from the base dimensions of the system—e.g., the square metre is the derived unit for area, which is derived from length.
Modigliani risk-adjusted performance (also known as M 2, M2, Modigliani–Modigliani measure or RAP) is a measure of the risk-adjusted returns of some investment portfolio. It measures the returns of the portfolio, adjusted for the risk of the portfolio relative to that of some benchmark (e.g., the market).
The metre per second squared is the unit of acceleration in the International System of Units (SI). As a derived unit , it is composed from the SI base units of length, the metre , and time, the second .