Speed of electromagnetic radiation

Einstein s second postulate requires the speed of electromagnetic radiation in free space to be the same for all inertial observers. The special theory of relativity (STR) is conventionally interpreted as a prohibition for the existence of a preferred frame S. 

Then, the principle of relativity simply states that all frames belonging to 5s are equivalent. Hence, in this limited context, Einstein s second postulate reduces to the statement that speed of electromagnetic radiation is a constant c in 5s. 

Let us postulate that we live in a 3D hypersurface that slides along the u axis with speed v°u = ca, where the u axis coincides with the arrow of time. The 4-velocity is then a (row or column) vector 1 a = ( ca,vx,vy,vz). The plus (resp. minus) sign corresponds to the speed of preons that enter (resp. leave) our 3D world, parallel (resp. antiparallel) to the time arrow. It will be seen below that this constant ca is the one that enters Einstein s mass-energy equation, and corresponds to the speed of our 3D world along the time axis (interpretation 2 in Fig. 1). The speed of electromagnetic radiation in free space is a different constant c. The value of the latter may be either identical or numerically close to c , depending of whether one adopts a relativistic or an emission theory for photons, respectively (see Section V). 

The following relationship exists between the wave frequency, v, and wavelength, X frequency times wavelength = velocity. Velocity refers to the speed of electromagnetic radiation waves in a vacuum. It is a constant (2.998 x 10 m/s), sometimes called the speed of light, c. 

The speed of electromagnetic radiation (c) is directly proportional to its wavelength and frequency ... 

In a vacuum, the speed of electromagnetic radiation, c, is the same for all wavelengths, 2.99792458 X 10 m/s. The relationship between the wavelength and frequency of electromagnetic radiation, with c rounded to three significant figures, is... 

What do we mean by the speed of electromagnetic radiation How do the frequency and the speed of electromagnetic radiation differ ... 

The speed of electromagnetic radiation represents how fast energy is transferred through space the frequency of the radiation tells us how many waves pass a given point in a certain amount of time. 

Based on the data in Table 1 and the relationship between speed, frequency, and wavelength, what is the speed of electromagnetic radiation (light waves) ... 

Symbol n. The absolute refractive Index of a medium is the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in that medium. As the refractive index varies with wavelength, the wavelength should be specified. It is usually given for yellow Ught (sodium D-lines wavelength 589.3 run). The relative refractive index is the ratio of the speed of light in one medium to that in an adjacent medium. See... 

The ratio of the speed of electromagnetic radiation in vacuum to that in a particular medium is known as the absolute index of refraction of the medium, n ... 

EXAMPLE 11.3 The vibrational partition function of O2. Oxygen molecules have a vibrational frequency of 1580cm To convert from cm to v, which has units of s multiply by the speed of electromagnetic radiation (hght) to get V = (1580cm-i)(2.997 x... 

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