What Is Electromagnetic Radiation

Plane-polarized electromagnetic radiation showing the electric field, the magnetic field, and the direction of propagation. 

Electric field component of plane-polarized electromagnetic radiation. 

The distance between any two consecutive maxima or minima of an electromagnetic wave (X). 

for electromagnetic radiation of frequency, V, the wavelength in vacuum is longer than in other media. Another unit used to describe the wave properties of electromagnetic radiation is the wavenumber, V, which is the reciprocal of wavelength 

Wavenumbers are frequently used to characterize infrared radiation, with the units given in reciprocal centimeter (cm ). 

The nature of electromagnetic radiation baffled scientists for many years. At times light appears to behave like a wave at other times it behaves as though it were composed of small particles. While we now understand the wave-particle duality of all matter, including electromagnetic radiation, in terms of quantum mechanics, it is still convenient to consider electromagnetic radiation as having the properties of waves in many cases. 

The frequency v of a wave is the number of crests passing a fixed point per second. One crest-to-crest oscillation of a wave is called a cycle. The common unit of frequency is the hertz (Hz) or inverse second (s ) an older term for frequency is the cycle per second (cps). One hertz equals one cycle per second. 

In some cases it is more convenient to consider light as a stream of particles. We call particles of light photons. Photons are characterized by their energy, E. The energy of a photon is related to the frequency of light by the equation  

The wavelength of light, X, is related to its frequency, v, by the following equation  

Purple 1 1 Red Orange 1 Yellow Green Blue 1 Violet 1 

Frequency (i/) A number of full cycles of a wave that pass a point In a second. 

Hertz (Hz) The unit In which wave frequency is reported (read per second). 

Wavelength is the distance between any two consecutive identical points on the wave. Wavelength is given the symbol A (Greek lowercase lambda) and is usually expressed in the SI base unit of meters. Other derived units commonly used to express wavelength are given in Table 11.2. 

The frequency of a vyave is the number of full cycles of the wave that pass a given point in a second. Frequency is given the symbol v (Greek nu) and is reported in hertz (Hz), which has the unit of reciprocal seconds (s ). Wavelength and frequency are inversely proportional, and we can calculate one from the other from the relationship 

Wavelength, Frequency, and Energy Relationships of Some Regions of the Electromagnetic Spectrum 

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O Copy and label the atom showing the locations O What is electromagnetic radiation Provide three of the electrons, protons, neutrons, and nucleus. examples. 

What is electromagnetic radiation At what speed does electromagnetic radiation travel ... 

What Is Electromagnetic Radiation 11.12 What Is C-NMR Spectroscopy, and How Does It... 

The most useful tool for studying the structure of atoms is electromagnetic radiation. What we call light is one form of this radiation. We need to know about the properties of light in order to understand what electromagnetic radiation reveals about atomic stmcture. 

SC What is thermal radiation How does it differ from the other forms of electromagnetic radiation ... 

The electric field of electromagnetic radiation completes 4.00 x lO - " complete cycles in 1.00 s. What are the period and frequency of the oscillation, and what is its wavelength What is the frequency in units of cm ... 

The hydrogen atom attached to an alkane molecule vibrates along the bond axis at a frequency of about 3000 cm. What wavelength of electromagnetic radiation is resonant with this vibration What is the frequency in hertz What is the force constant of the C II bond if the alkane is taken to be a stationary mass because of its size and the H atom is assumed to execute simple harmonic motion ... 

Mass spectrometry is not based on absorption of electromagnetic radiation, but monitors what happens when a substance is ionized by collision with a high-energy electron. 

Figure 12.11 Electromagnetic waves are characterized by a wavelength, a frequency, and an amplitude, (a) Wavelength (A) is the distance between two successive wave maxima. Amplitude is the height of the wave measured from the center. (b)-(c) What we perceive as different kinds of electromagnetic radiation are simply waves with different wavelengths and frequencies.

Self-Test 1.3A In 1965, electromagnetic radiation with a maximum at 1.05 mm (in the microwave region) was discovered to pervade the universe. What is the temperature of empty space ... 

Diffraction of electromagnetic radiation by atoms and molecules occurs when the wavelength of the electromagnetic radiation is similar to the size of the particle that causes the diffraction—in this case, atoms or molecules, (a) Using 2.0 X 102 pm as the diameter of an atom, decide what type(s) of... 

The energy required to break a C-C bond in a molecule is 348 kJ-moD1. Will visible light be able to break this bond If yes, what is the color of that light If not, what type of electromagnetic radiation will be suitable ... 

What Is Interferometry (1.3) Interferometry deals with the physical phenomena which result from the superposition of electromagnetic (e.m.) waves. Practically, interferometry is used throughout the electromagnetic spectrum astronomers use predominantly the spectral regime from radio to the near UV. Essential to interferometry is that the radiation emerges from a single source and travels along different paths to the point where it is detected. The spatio-temporal coherence characteristics of the radiation is studied with the interferometer to obtain information about the physical nature of the source. 

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