Search results
Results From The WOW.Com Content Network
The temperature determines the wavelength distribution of the electromagnetic radiation. The distribution of power that a black body emits with varying frequency is described by Planck's law. At any given temperature, there is a frequency f max at which the power emitted is a maximum.
The Doppler effect (also Doppler shift) is the change in the frequency of a wave in relation to an observer who is moving relative to the source of the wave. [ 1 ] [ 2 ] [ 3 ] The Doppler effect is named after the physicist Christian Doppler , who described the phenomenon in 1842.
Each temperature curve peaks at a different wavelength and Wien's law describes the shift of that peak. There are a variety of ways of associating a characteristic wavelength or frequency with the Planck black-body emission spectrum. Each of these metrics scales similarly with temperature, a principle referred to as Wien's displacement law.
The vibrational temperature is commonly used in thermodynamics, to simplify certain equations.It has units of temperature and is defined as = ~ = where is the Boltzmann constant, is the speed of light, ~ is the wavenumber, and (Greek letter nu) is the characteristic frequency of the oscillator.
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 wavelength. As waves cross boundaries between different media, their speeds change but their frequencies remain constant. Electromagnetic waves in free space must be solutions of Maxwell's electromagnetic wave equation. Two main classes of ...
If we consider the angles relative to the frame of the source, then = and the equation reduces to Equation 7, Einstein's 1905 formula for the Doppler effect. If we consider the angles relative to the frame of the receiver, then v r = 0 {\\displaystyle v_{r}=0} and the equation reduces to Equation 6 , the alternative form of the Doppler shift ...
The equation says the matter wave frequency in vacuum varies with wavenumber (= /) in the non-relativistic approximation. The variation has two parts: a constant part due to the de Broglie frequency of the rest mass ( ℏ ω 0 = m 0 c 2 {\displaystyle \hbar \omega _{0}=m_{0}c^{2}} ) and a quadratic part due to kinetic energy.
A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.