Electromagnetic Radiation
Electromagnetic Radiation - Related Videos
01:10
Generating Electromagnetic Radiations
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2025
The German physicist Heinrich Hertz (1857–1894) was the first to generate and detect certain types of electromagnetic waves in the laboratory. Starting in 1887, he performed a series of experiments that confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz used an alternating-current RLC (resistor-inductor-capacitor) circuit that resonated at a known frequency and connected it to a loop of wire. High voltages induced across the gap in the...
02:37
The Electromagnetic Spectrum
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2020
The electromagnetic spectrum consists of all the types of electromagnetic radiation arranged according to their frequency and wavelength. Each of the various colors of visible light has specific frequencies and wavelengths associated with them, and you can see that visible light makes up only a small portion of the electromagnetic spectrum. Because the technologies developed to work in various parts of the electromagnetic spectrum are different, for reasons of convenience and historical...
01:10
Dual Nature of Electromagnetic (EM) Radiation
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2024
Electromagnetic (EM) radiation consists of electric and magnetic field components oscillating in planes perpendicular to each other and mutually perpendicular to radiation propagation through space. EM radiation can be classified as a wave, characterized by the properties of waves such as wavelength (denoted as λ) and frequency (represented by ν). Wavelength is the distance between two consecutive peaks (the highest point) or troughs (the lowest point) in the wave. Frequency is the number of...
02:59
Biological Effects of Radiation
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2020
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...
08:17
Dynamic Lung Tumor Tracking for Stereotactic Ablative Body Radiation Therapy
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Cited by 9 •
2015
Stereotactic ablative body radiation therapy (SBRT) involves the precise delivery of high-dose radiation to cancer tumor targets. A novel SBRT platform offers a first-of-its-kind gimbaled radiation accelerator mounted within a pivoting O-ring gantry capable of dynamic image-guided tumor tracking. Here, we describe dynamic tumor tracking for lung targets.
FAQs
Wavelength and frequency describe the wave behavior of electromagnetic radiation, while photon energy increases in proportion to frequency. Consequently, changing the radiation's frequency changes the energy available for interaction with matter. Spectroscopic measurements exploit these differences because molecules respond to specific wavelengths, producing patterns of absorption, emission, reflection, or transmission that can be analyzed chemically.
Molecular interactions are wavelength-specific, so a molecule may absorb, emit, reflect, or transmit some portions of electromagnetic radiation more strongly than others. These selective responses create measurable patterns rather than uniform signals. Chemists use the resulting patterns to obtain information about molecular structure, bonding, and composition, making wavelength selection central to spectroscopic analysis.
Infrared, ultraviolet-visible, and nuclear magnetic resonance methods are distinct spectroscopic approaches that use electromagnetic interactions to examine chemical matter. Together, they can reveal molecular structure, bonding, and composition, although each method provides its own measurement perspective. Comparing results from these techniques can therefore give a more complete chemical description than relying on a single method.
Quantitative analysis can connect a measured absorbance with the concentration of a chemical species. A sample's absorbance is recorded under selected measurement conditions, and that value is related to concentration through the applicable calibration relationship. This approach converts an optical measurement into compositional information, allowing chemists to assess how much of a species is present.
A basic workflow begins by exposing a sample to electromagnetic radiation and measuring how the sample responds. The observed absorption, emission, reflection, or transmission is then examined at relevant wavelengths. Depending on the selected method, the resulting data can be interpreted to identify molecular structure, bonding, or composition, or to support quantitative concentration analysis.
Electromagnetic radiation can provide the interaction that initiates a photochemical reaction. When matter responds to suitable radiation, the absorbed energy can be associated with chemical change rather than observation alone. This makes radiation useful both as an analytical probe in spectroscopy and as a means of manipulating chemical systems through light-driven processes.