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Ultraviolet (UV) filters block ultraviolet radiation, but let visible light through. Because photographic film and digital sensors are sensitive to ultraviolet (which is abundant in skylight) but the human eye is not, such light would, if not filtered out, make photographs look different from the scene visible to people, for example making ...
A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave ultraviolet light and very little visible light. [ 1 ] [ 2 ] [ 3 ] One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV ...
A conductive enclosure used to block electrostatic fields is also known as a Faraday cage. The amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of holes in a shield to an incident electromagnetic field.
The spectrum of light emitted from a fluorescent lamp is the combination of light directly emitted by the mercury vapor, and light emitted by the phosphorescent coating. The spectral lines from the mercury emission and the phosphorescence effect give a combined spectral distribution of light that is different from those produced by incandescent ...
Liquid crystals are birefringent, so applying a voltage to the cell changes the effective refractive index seen by the incident wave, and thus the phase retardation of the reflected wave. A spatial light modulator ( SLM ) is a device that can control the intensity , phase , or polarization of light in a spatially varying manner.
Light scattering in liquids and solids depends on the wavelength of the light being scattered. Limits to spatial scales of visibility (using white light) therefore arise, depending on the frequency of the light wave and the physical dimension (or spatial scale) of the scattering center. Visible light has a wavelength scale on the order of 0.5 μm.
Two systems are common: plasma lamps, in which microwaves or radio waves, energizes a bulb filled with sulfur vapor [1] or metal halides, and fluorescent induction lamps, which are like a conventional fluorescent lamp bulb that induces current with an external or an internal coil of wire via electromagnetic induction.
In 1966, Eugene Alessio patented a light bulb socket adapter for adjusting a light level on a single light bulb using a triac. To house this device, he decided on a 2-inch round device with one end capable of being screwed into a light bulb socket and the other end able to receive a light bulb. [4]