Although the metre is now defined as the path length travelled by light in a given time, the practical laboratory length measurements in metres are determined by counting the number of wavelengths of laser light of one of the standard types that fit into the length, and converting the selected unit of wavelength to metres.

Although the birefringence Δn may vary slightly due to dispersion, this is negligible compared to the variation in phase difference according to the wavelength of the light due to the fixed path difference ( λ < sub > 0 </ sub > in the denominator in the above equation ).

Although Classical electromagnetism predicted that the wavelength of scattered rays should be equal to the initial wavelength, multiple experiments had found that the wavelength of the scattered rays was longer ( corresponding to lower energy ) than the initial wavelength.

Although wavelength dispersive spectrometers are occasionally used to scan a wide range of wavelengths, producing a spectrum plot as in EDS, they are usually set up to make measurements only at the wavelength of the emission lines of the elements of interest.

Although invisible to the naked eye, the dot produced by this laser mouse is captured as the color purple because CCDs are sensitive to a broader light wavelength range than the human eye.

Although it is commonly believed that the layers in negative papers are shielded against the intrusion of light of a different wavelength than the actual layer by color filters which dissolve during processing, this is not so.

Although laser light is perhaps the purest form of light, it is not of a single, pure frequency or wavelength.

Although the emission lines are caused by a transition between quantized energy states and may at first look very sharp, they do have a finite width, i. e. they are composed of more than one wavelength of light.

Although this wavelength can be obtained directly with an inexpensive laser diode, higher beam quality and narrower spectral bandwidth are achieved through DPSS versions.

Although the TV service was not developed, the coaxial cable buried between buildings allowed the radio station to broadcast on an FM wavelength.

Although these nebulae have different visibility at optical wavelengths, they are all bright sources of infrared emission, chiefly from dust within the nebulae.

Although the term commonly refers to wireless data transfer mechanisms ( e. g. using radio, hypersonic or infrared systems ), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like phase line carriers.

Although there is much overlap in the requirements and use of instruments, ordinary CD instruments are usually optimized for operation in the ultraviolet, approximately 170 – 300 nm, while MCD instruments are typically required to operate in the visible to near infrared, approximately 300 – 2000 nm.

Although seeing in the infrared, the UKIRT was large for an optical telescopes and signaled a coming focus on this part of the spectrum that only grew in the coming decades.

Although OBEX was initially designed for infrared, it has now been adopted by Bluetooth, and is also used over RS232, USB, WAP, and in devices such as Livescribe smartpens.

Although many methods are available for observing vibrational spectra, the two most common methods are infrared spectroscopy and Raman spectroscopy.

Although the Navy and Air Force initially planned additional upgrades for the Sparrow, notably the AIM-7R with a combination radar / infrared seeker, these were canceled in favor of the much more advanced AIM-120 AMRAAM in December 1996.

Although fuel cell technology is not as accurate or reliable as infrared spectroscopy technology used in evidentiary breathalyzers, they are cheaper and tend to be more specific for alcohol.

Although initially a blessing, this later works to Pieter's disadvantage in the field, as he is no longer able to see through his own dark bombs, and the loss of his infrared vision prevents him from saving a mortally-wounded Lance.

Although the technique uses the same part of the electromagnetic spectrum as infrared ( IR ) spectroscopy, the two methods are actually complementary.

Although air has very low emissivity ( emits very small amounts of infrared energy ), the air blowing on the plastic window cover could change the plastic's temperature enough to triger a false alarm.

Although infrared light-emitting diodes and lasers have been made in HgCdTe, they must be operated cold to be efficient.

Although all aggregate configurations cause absorption in the infrared, diamonds containing aggregated nitrogen are usually colorless, i. e. have little absorption in the visible spectrum.

Although this leads to no problems at the leading order in the 1 / N expansion, massless particles in 2-dimensional quantum field theories inevitably lead to infrared divergences and so the theory appears to not exist.

Although the element is only mildly toxic, it is a hazardous material as a metal and its radioisotopes present a high health risk in case of radiation leaks.

Although X-rays are most commonly used, the beam is not always electromagnetic radiation.

Although modern quantum optics tells us that there also is a semi-classical explanation of the photoelectric effect — the emission of electrons from metallic surfaces subjected to electromagnetic radiation — the photon was historically ( although not strictly necessarily ) used to explain certain observations.

Although hair provides protection against harmful UV radiation, since our hominin ancestors were bipedal, only our heads were exposed to the noonday sun.

Although nuclear testing was halted in 1990, radiation poisoning, birth defects, severe anemia, and leukemia are very common in the area.

Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet ( UV ) radiation coming from the sun.

Although it is often claimed that the photoelectric and Compton effects require a quantum description of the EM field, this is now understood to be untrue, and proper proof of the quantum nature of radiation is now taken up into modern quantum optics as in the antibunching effect.

Although nearly all of the ultraviolet spectrum of radiation is non-ionizing, at the same time ultraviolet radiation does far more damage to many molecules in biological systems than is accounted for by heating effects ( an example is sunburn ).

Although ultraviolet radiation is invisible to the human eye, most people are aware of the effects of UV on the skin, called suntan and sunburn.

Although their extreme blast and heat effects are not eliminated, it is the enormous radiation released by ERWs that is meant to be a major source of casualties.

Although not usually a factor in the thermal radiation of stars, polarization is also present in radiation from coherent astronomical sources ( e. g. hydroxyl or methanol masers ), and incoherent sources such as the large radio lobes in active galaxies, and pulsar radio radiation ( which may, it is speculated, sometimes be coherent ), and is also imposed upon starlight by scattering from interstellar dust.

Although the exposure might be minimal, many people find radiation exposure especially frightening because it is something they cannot see or feel, and it therefore becomes an unknown source of danger.

Although the detonation of a dirty bomb using such a source might seem terrifying, it would be hard to assemble the bomb and transport it without severe radiation damage and possible death of the perpetrators involved.

* 1948-Ralph Alpher and Robert Herman estimate " the temperature in the Universe " at 5 K. Although they do not specifically mention microwave background radiation, it may be inferred.

For a hypothetical proton lifetime of 10 < sup > 37 </ sup > years, Adams and Laughlin calculate that proton decay will raise the effective surface temperature of an old one-solar mass white dwarf to approximately 0. 06 K. Although cold, this is thought to be hotter than the temperature that the cosmic background radiation will have 10 < sup > 37 </ sup > years in the future .< sup >, § IVB .</ sup >

Although causation cannot be confirmed in these cases, caution should still be used when prescribing radiation therapy for keloids, particularly when treating younger patients. It may occasionally be appropriate as treatment for keloids resistant to other therapies.

) Although radiation levels in the water have declined over time, the longer-lived isotopes will continue to pose risks for tens of thousands of years.

Although such an antenna is resonant and works perfectly well at the higher frequency, the antenna radiation pattern is also altered compared to the half-wave dipole.

Although their exteriors are subjected to intense solar radiation that can alter their chemistry, their interiors contain pristine material essentially untouched since the planetesimal was formed.

Although there are claims that participants in the Crossroads tests were well protected against radiation sickness, the Oscar-nominated documentary Radio Bikini showed footage of Navy sailors wearing little or no protection during their inspection of the target ships only hours after the explosions, even though some of the observer ships were caught in the fallout of the Baker explosion.

Although trained in the delivery of chemotherapy, radiation oncologists in Australia and New Zealand rarely prescribe it.

Although the radiation of an omnidirectional antenna is symmetrical in azmuthal directions, it may vary in a complicated way with elevation angle, having lobes and nulls at different angles.