Nu (/ˈnjuː/ ; uppercase Ν, lowercase ν; Greek: vι ni, [ni]) is the thirteenth letter of the Greek alphabet, representing the voiced alveolar nasal [n]. In the system of Greek numerals it has a value of 50. It is derived from the Phoenician nun 
. Its Latin equivalent is N, though the lowercase () resembles the Roman lowercase v.
The name of the letter is νῦ (nû, [nŷː]) in Ancient Greek, while in Modern Greek it is νι (ni, [ni]).
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Rotational frequency, also known as rotational speed or rate of rotation (symbols ν, lowercase Greek nu, and also n), is the frequency of rotation of an object around an axis.Its SI unit is the reciprocal seconds (s); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm).
Rotational frequency can be obtained dividing angular frequency, ω, by a full turn (2π radians): ν=ω/(2π rad).It can also be formulated as the instantaneous rate of change of the number of rotations, N, with respect to time, t: n=dN/dt (as per International System of Quantities).Similar to ordinary period, the reciprocal of rotational frequency is the rotation period or period of rotation, T=ν=n, with dimension of time (SI unit seconds).
A neutrino (/njuːˈtriːnoʊ/ new-TREE-noh; denoted by the Greek letter ν) is an elementary particle that interacts via the weak interaction and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small (-ino) that it was long thought to be zero. The rest mass of the neutrino is much smaller than that of the other known elementary particles (excluding massless particles).The weak force has a very short range, the gravitational interaction is extremely weak due to the very small mass of the neutrino, and neutrinos do not participate in the electromagnetic interaction or the strong interaction.Consequently, neutrinos typically pass through normal matter unimpeded and with no detectable effect.
Weak interactions create neutrinos in one of three leptonic flavors:
The cosmic neutrino background is a proposed background particle radiation composed of neutrinos. They are sometimes known as relic neutrinos or sometimes abbreviated CNB or CνB, where the symbol ν is the Greek letter nu, standard particle physics symbol for a neutrino.
The CνB is a relic of the Big Bang; while the cosmic microwave background radiation (CMB) dates from when the universe was 379,000 years old, the CνB decoupled (separated) from matter when the universe was just one second old. It is estimated that today, the CνB has a temperature of roughly 1.95 K.
Nun is the fourteenth letter of the Semitic abjads, including Phoenician nūn 𐤍, Hebrew nūn נ, Aramaic nūn 𐡍, Syriac nūn ܢ, and Arabic nūn ن (in abjadi order). Its numerical value is 50. It is the third letter in Thaana (ނ), pronounced as "noonu". In all languages, it represents the alveolar nasal /n/. It is related to the Ancient North Arabian 𐪌, South Arabian 𐩬, and Ge'ez ነ.
The Phoenician letter gave rise to the Greek nu (Ν), Etruscan 
, Latin N, and Cyrillic Н.
The quantum Hall effect (or integer quantum Hall effect) is a quantized version of the Hall effect which is observed in two-dimensional electron systems subjected to low temperatures and strong magnetic fields, in which the Hall resistance Rxy exhibits steps that take on the quantized values
where VHall is the Hall voltage, Ichannel is the channel current, e is the elementary charge and h is the Planck constant. The divisor ν can take on either integer (ν = 1, 2, 3,...) or fractional (ν = 1/3, 2/5, 3/7, 2/3, 3/5, 1/5, 2/9, 3/13, 5/2, 12/5,...) values. Here, ν is roughly but not exactly equal to the filling factor of Landau levels. The quantum Hall effect is referred to as the integer or fractional quantum Hall effect depending on whether ν is an integer or fraction, respectively.
In thermodynamics, the specific volume of a substance (symbol: ν, nu) is the quotient of the substance's volume (V) to its mass (m):
It is a mass-specific intrinsic property of the substance. It is the reciprocal of density ρ (rho) and it is also related to the molar volume and molar mass:
