Electromagnetic spectrum - Wikipedia
In the electromagnetic spectrum there are many different types of waves with this relationship to figure out the wavelength or frequency of any electromagnetic . of electromagnetic radiation according to frequency or wavelength. of the corresponding waves and also based on their different practical applications. Waves and their Characteristics Longer wavelength waves such as radio waves carry low energy; this is why we can listen to the radio without any harmful consequences. This wavelength frequently relationship is characterized by: Frequency is directly proportional to energy and can be express as.
Until recently, the range was rarely studied and few sources existed for microwave energy at the high end of the band sub-millimeter waves or so-called terahertz wavesbut applications such as imaging and communications are now appearing.
Electromagnetic Spectrum - Wavelength, Frequency, And Energy, Wavelength Regions
Scientists are also looking to apply terahertz technology in the armed forces, where high-frequency waves might be directed at enemy troops to incapacitate their electronic equipment. Infrared radiation Main article: It can be divided into three parts: The lower part of this range may also be called microwaves or terahertz waves. This radiation is typically absorbed by so-called rotational modes in gas-phase molecules, by molecular motions in liquids, and by phonons in solids.
The water in Earth's atmosphere absorbs so strongly in this range that it renders the atmosphere in effect opaque. However, there are certain wavelength ranges "windows" within the opaque range that allow partial transmission, and can be used for astronomy.
Mid-infrared, from 30 to THz 10—2. Hot objects black-body radiators can radiate strongly in this range, and human skin at normal body temperature radiates strongly at the lower end of this region. This radiation is absorbed by molecular vibrations, where the different atoms in a molecule vibrate around their equilibrium positions.
This range is sometimes called the fingerprint region, since the mid-infrared absorption spectrum of a compound is very specific for that compound. Physical processes that are relevant for this range are similar to those for visible light.
The highest frequencies in this region can be detected directly by some types of photographic film, and by many types of solid state image sensors for infrared photography and videography. Visible radiation light Main article: Visible spectrum Above infrared in frequency comes visible light. The Sun emits its peak power in the visible region, although integrating the entire emission power spectrum through all wavelengths shows that the Sun emits slightly more infrared than visible light.
Visible light and near-infrared light is typically absorbed and emitted by electrons in molecules and atoms that move from one energy level to another. This action allows the chemical mechanisms that underlie human vision and plant photosynthesis.
The light that excites the human visual system is a very small portion of the electromagnetic spectrum. A rainbow shows the optical visible part of the electromagnetic spectrum; infrared if it could be seen would be located just beyond the red side of the rainbow with ultraviolet appearing just beyond the violet end. White light is a combination of lights of different wavelengths in the visible spectrum. If radiation having a frequency in the visible region of the EM spectrum reflects off an object, say, a bowl of fruit, and then strikes the eyes, this results in visual perception of the scene.
The brain's visual system processes the multitude of reflected frequencies into different shades and hues, and through this insufficiently-understood psychophysical phenomenon, most people perceive a bowl of fruit.
At most wavelengths, however, the information carried by electromagnetic radiation is not directly detected by human senses. Natural sources produce EM radiation across the spectrum, and technology can also manipulate a broad range of wavelengths. Optical fiber transmits light that, although not necessarily in the visible part of the spectrum it is usually infraredcan carry information.
The modulation is similar to that used with radio waves. Ultraviolet radiation Main article: The wavelength of UV rays is shorter than the violet end of the visible spectrum but longer than the X-ray.
electromagnetic spectrum | Definition, Diagram, & Uses | blogmaths.info
UV is the longest wavelength radiation whose photons are energetic enough to ionize atoms, separating electrons from them, and thus causing chemical reactions. Short wavelength UV and the shorter wavelength radiation above it X-rays and gamma rays are called ionizing radiationand exposure to them can damage living tissue, making them a health hazard. UV can also cause many substances to glow with visible light; this is called fluorescence. At the middle range of UV, UV rays cannot ionize but can break chemical bonds, making molecules unusually reactive.
Sunburnfor example, is caused by the disruptive effects of middle range UV radiation on skin cellswhich is the main cause of skin cancer. UV rays in the middle range can irreparably damage the complex DNA molecules in the cells producing thymine dimers making it a very potent mutagen. However, most of the Sun's damaging UV wavelengths are absorbed by the atmosphere before they reach the surface.
The higher energy shortest wavelength ranges of UV called "vacuum UV" are absorbed by nitrogen and, at longer wavelengths, by simple diatomic oxygen in the air. As a particle, EM is represented as a photon, which transports energy.
When a photon is absorbed, the electron can be moved up or down an energy level. When it moves up, it absorbs energy, when it moves down, energy is released. Thus, since each atom has its own distinct set of energy levels, each element emits and absorbs different frequencies. Photons with higher energies produce shorter wavelengths and photons with lower energies produce longer wavelengths. Photon Before and After Emission Ionizing and Non-Ionizing Radiation Electromagnetic Radiation is also categorized into two groups based, ionizing and non-ionizing, on the severity of the radiation.
Ionizing radiation holds a great amount of energy to remove electrons and cause the matter to become ionized. Thus, higher frequency waves such as the X-rays and gamma-rays have ionizing radiation. However, lower frequency waves such as radio waves, do not have ionizing radiation and are grouped as non-ionizing.What is the Electromagnetic Spectrum?
Electromagnetic Radiation and Temperature Electromagnetic radiation released is related to the temperature of the body. Stephan-Boltzmann Law says that if this body is a black body, one which perfectly absorbs and emits radiation, the radiation released is equal to the temperature raised to the fourth power. Therefore, as temperature increases, the amount of radiation released increases greatly. Objects that release radiation very well also absorb radiation at certain wavelengths very well.
Wavelengths are also related to temperature.
As the temperature increases, the wavelength of maximum emission decreases. Problems What is the wavelength of a wave with a frequency of 4.
What is the frequency of a wave with a wavelength of cm? What is the frequency of a wave with a wavelength of pm? What is the wavelength of a wave with a frequency of 2. A radio transmits a frequency of Hz.
What is the wavelength of this wave?