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The wave associated with a particle of a given mass, such as an atom, has a defined frequency, and a change in the duration of one cycle from peak to peak that is sometimes called its Compton periodicity. Such a matter wave has the characteristics of a simple clock, in that it marks out fixed and equal intervals of time.
Longer-wavelength radiation such as visible light is nonionizing; the photons do not have sufficient energy to ionize atoms. Throughout most of the electromagnetic spectrum, spectroscopy can be used to separate waves of different frequencies, so that the intensity of the radiation can be measured as a function of frequency or wavelength ...
Waves of the electromagnetic spectrum vary in size, from very long radio waves longer than a continent to very short gamma rays smaller than atom nuclei. Frequency is inversely proportional to wavelength, according to the equation: [26] = where v is the speed of the wave (c in a vacuum or less in other media), f is the frequency and λ is the ...
His thesis started from the hypothesis, "that to each portion of energy with a proper mass m 0 one may associate a periodic phenomenon of the frequency ν 0, such that one finds: hν 0 = m 0 c 2. The frequency ν 0 is to be measured, of course, in the rest frame of the energy packet. This hypothesis is the basis of our theory."
The Planck relation [1] [2] [3] (referred to as Planck's energy–frequency relation, [4] the Planck–Einstein relation, [5] Planck equation, [6] and Planck formula, [7] though the latter might also refer to Planck's law [8] [9]) is a fundamental equation in quantum mechanics which states that the energy E of a photon, known as photon energy, is proportional to its frequency ν: =.
For example, the photons emitted by a radio station broadcast at the frequency ν = 100 MHz, have an energy content of νh = (1 × 10 8) × (6.6 × 10 −34) = 6.6 × 10 −26 J, where h is the Planck constant. The wavelength of the station is λ = c/ν = 3 m, so that λ/(2π) = 48 cm and the volume is 0.109 m 3.
The 41.8% point is the wavelength-frequency-neutral peak (i.e. the peak in power per unit change in logarithm of wavelength or frequency). These are the points at which the respective Planck-law functions 1 / λ 5 , ν 3 and ν 2 / λ 2 , respectively, divided by exp ( hν / k B T ) − 1 attain their maxima.
Tuning dial on 1946 Dynatron Merlin T.69 console radio receiver, showing LW wavelengths between 800 and 2000 metres (375–150 kHz). In radio, longwave, long wave or long-wave, [1] and commonly abbreviated LW, [2] refers to parts of the radio spectrum with wavelengths longer than what was originally called the medium-wave broadcasting band.