News tagged with wavelength

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Crag keeps the light 'fantastic' for photoreceptors

The ability of the eye of a fruit fly (Drosophila melanogaster) to respond to light depends on a delicate ballet that keeps the supply of light sensors called rhodopsin constant as photoreceptors turn on and off in respon ...

Dec 04, 2012
popularity 5 / 5 (1) | comments 0 | with audio podcast

'White' light suppresses the body's production of melatonin

Exposure to the light of white LED bulbs, it turns out, suppresses melatonin 5 times more than exposure to the light of High Pressure Sodium bulbs that give off an orange-yellow light. "Just as there are regulations and standards ...

Sep 12, 2011
popularity 5 / 5 (19) | comments 23 | with audio podcast

New technology shows diabetes

A new imaging method for the study of insulin-producing cells in diabetes among other uses is now being presented by a group of researchers at Umeå University in Sweden in the form of a video in the biomedical ...

Jan 21, 2013
popularity 5 / 5 (1) | comments 0

Wavelength

In physics, the wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats. It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves. Wavelength is commonly designated by the Greek letter lambda (λ). The concept can also be applied to periodic waves of non-sinusoidal shape. The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.

Examples of wave-like phenomena are sound waves, light, and water waves. A sound wave is a periodic variation in air pressure, while in light and other electromagnetic radiation the strength of the electric and the magnetic field vary. Water waves are periodic variations in the height of a body of water. In a crystal lattice vibration, atomic positions vary periodically in both lattice position and time.

Wavelength is a measure of the distance between repetitions of a shape feature such as peaks, valleys, or zero-crossings, not a measure of how far any given particle moves. For example, in waves over deep water a particle in the water moves in a circle of the same diameter as the wave height, unrelated to wavelength.

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