part_of optical filter
Carbon ( from " coal ") is a chemical element with symbol ___MASK62___ and atomic number 6 . It is nonmetallic and tetravalent  making four electrons available to form covalent chemical bonds . Three isotopes occur naturally , ___MASK62___ and ___MASK62___ being stable , while ___MASK62___ is a radioactive isotope , decaying with a half - life of about 5 , 730 years . Carbon is one of the few elements known since antiquity . A ___MASK35___ is an opening in a ___MASK41___ , door , roof or vehicle that allows the passage of light and , if not closed or sealed , air and sound . ___MASK64___ is the branch of physics which involves the behaviour and properties of light , including its interactions with matter and the construction of instruments that use or detect it . ___MASK64___ usually describes the behaviour of visible , ultraviolet , and infrared light . Because light is an electromagnetic wave , other forms of electromagnetic radiation such as X - rays , microwaves , and radio waves exhibit similar properties . A bottle is a rigid container with a neck that is narrower than the ___MASK58___ and a ___MASK51___ . By contrast , a jar has a relatively large ___MASK51___ or opening which ___MASK69___ be as wide as the overall container . Bottles are often made of glass , clay , plastic , aluminium or other impervious materials , and typically used to store liquids such as water , milk , soft drinks , beer , wine , cooking oil , medicine , shampoo , ink , and chemicals . A device applied in the bottling line to seal the ___MASK51___ of a bottle is termed an external bottle cap , closure , or internal stopper . A bottle can also be sealed by a conductive " innerseal " by using induction sealing . Silicon dioxide , also known as silica ( from the Latin " silex "), is a chemical compound that is an oxide of silicon with the chemical formula . It has been known since ancient times . Silica is most commonly found in ___MASK34___ as quartz , as well as in various living organisms . In many parts of the world , silica is the major constituent of sand . Silica is one of the most complex and most abundant families of materials , existing both as several minerals and being produced synthetically . Notable examples include fused quartz , crystal , fumed silica , silica gel , and aerogels . Applications range from structural materials to microelectronics to components used in the ___MASK61___ . Glass is a non - crystalline amorphous ___MASK71___ that is often transparent and has widespread practical , technological , and decorative usage in , for example , window panes , tableware , and optoelectronics . The most familiar , and historically the oldest , types of glass are " silicate glasses " based on the chemical compound silica ( silicon dioxide , or quartz ), the primary constituent of sand . The term " glass ", in popular usage , is often used to refer only to this type of material , which is familiar from use as window glass and in glass bottles . Of the many silica - based glasses that exist , ordinary glazing and container glass is formed from a specific type called soda - lime glass , composed of approximately 75 % silicon dioxide ( SiO ), sodium oxide ( NaO ) from sodium carbonate ( NaCO ), calcium oxide , also called lime ( CaO ), and several minor additives . Calcium oxide ( CaO ), commonly known as quicklime or burnt lime , is a widely used chemical compound . It is a white , caustic , alkaline , crystalline ___MASK71___ at room temperature . The broadly used term " lime " connotes calcium - containing inorganic materials , in which carbonates , oxides and hydroxides of calcium , silicon , magnesium , aluminium , and iron predominate . By contrast , " quicklime " specifically applies to the single chemical compound calcium oxide . Calcium oxide which survives processing without reacting in building products such as cement is called free lime . Tableware is the dishes or dishware used for setting a table , serving food and dining . It includes ___MASK99___ , glassware , serving dishes and other useful items for practical as well as decorative purposes . The quality , nature , ___MASK30___ and number of objects varies according to culture , religion , number of diners , cuisine and occasion . For example , Middle Eastern , Indian or Polynesian food culture and cuisine sometimes limits tableware to serving dishes , using bread or leaves as individual plates . Special occasions are usually reflected in higher quality tableware . Optoelectronics is the study and application of ___MASK9___ devices and systems that source , detect and control light , usually considered a sub - field of photonics . In this context , " light " often includes invisible forms of ___MASK24___ such as gamma rays , X - rays , ultraviolet and infrared , in addition to visible light . Optoelectronic devices are electrical - to - optical or optical - to - electrical transducers , or instruments that use such devices in their operation . " Electro - ___MASK64___ " is often erroneously used as a synonym , but is a wider branch of physics that concerns all interactions between light and electric fields , whether or not they form part of an ___MASK9___ device . In condensed matter ___MASK76___ and ___MASK98___ , an amorphous ( from the Greek " a ", without , " morphé ", shape , form ) or non - crystalline ___MASK71___ is a ___MASK71___ that lacks the long - range order that is characteristic of a crystal . In some older books , the term has been used synonymously with glass . Nowadays , " Glassy ___MASK71___ " or " Amorphous ___MASK71___ " is considered to be the overarching concept , and glass the more special case : A glass is an amorphous ___MASK71___ that exhibits a glass transition . Polymers are often amorphous . Other types of amorphous solids include gels , thin films , and nanostructured materials such as glass . In ___MASK64___ , optical path length ( OPL ) or optical distance is the product of the geometric length of the path light follows through the system , and the index of refraction of the medium through which it propagates . A difference in optical path length between two paths is often called the optical path difference ( OPD ). Optical path length is important because it determines the phase of the light and governs interference and diffraction of light as it propagates . Quartz is the second most abundant mineral in ___MASK77___ ' s continental crust , after feldspar . Its crystal structure is a continuous framework of SiO silicon  oxygen tetrahedra , with each oxygen being shared between two tetrahedra , giving an overall chemical formula of SiO . Sand is a naturally occurring granular material composed of finely divided ___MASK94___ and mineral particles . It is defined by size , being finer than gravel and coarser than silt . Sand can also refer to a textural class of soil or soil type ; i . e . a soil containing more than 85 % sand - sized particles by ___MASK89___ . Optical filters are devices that selectively transmit light of different wavelengths , usually implemented as plane glass or plastic devices in the optical path which are either dyed in the bulk or have interference coatings . The optical properties of filters are completely described by their frequency response , which specifies how the magnitude and phase of each frequency component of an incoming signal is modified by the filter . Filters mostly belong to one of two categories . The simplest , physically , is the absorptive filter ; then there are interference or dichroic filters . Optical filters selectively transmit light in a particular range of wavelengths , that is , colours , while blocking the remainder . They can usually pass long wavelengths only ( longpass ) , short wavelengths only ( shortpass ) , or a band of wavelengths , blocking both longer and shorter wavelengths ( bandpass ) . The passband ___MASK69___ be narrower or wider ; the transition or cutoff between maximal and minimal transmission can be sharp or gradual . There are filters with more complex transmission characteristic , for example with two peaks rather than a single band ; these are more usually older designs traditionally used for photography ; filters with more regular characteristics are used for scientific and technical work . Optical filters are commonly used in photography ( where some special effect filters are occasionally used as well as absorptive filters ) , in many optical instruments , and to colour stage lighting . In astronomy optical filters are used to restrict light passed to the spectral band of interest , e . g . , to study infrared radiation without visible light which would affect film or sensors and overwhelm the desired infrared . Optical filters are also essential in fluorescence applications such as fluorescence microscopy and fluorescence spectroscopy . Photographic filters are a particular case of optical filters , and much of the material here applies . Photographic filters do not need the accurately controlled optical properties and precisely defined transmission curves of filters designed for scientific work , and sell in larger quantities at correspondingly lower prices than many laboratory filters . Some photographic effect filters , such as star effect filters , are not relevant to scientific work . Folded ___MASK64___ is an optical system in which the beam is bent in a way to make the optical path much longer than the size of the system . Prismatic binoculars are a well - known example . The path that light takes in traversing an optical is often called the optical path . The physical length of an optical device can be reduced to less than the length of the optical path by using folded ___MASK64___ . The optical path length as defined in ___MASK64___ is the length of the path multiplied by the index of refraction of the medium .