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Properties of Matter and the Analysis of Glass. Properties of Light. Light as a Wave. Light can act as a wave that transmits energy through space Light waves are characterized by wavelength and frequency. Electromagnetic Spectrum. Light waves travel at the speed of light in a vacuum
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Properties of Matter and the Analysis of Glass Properties of Light
Light as a Wave • Light can act as a wave that transmits energy through space • Light waves are characterized by wavelength and frequency
Electromagnetic Spectrum • Light waves travel at the speed of light in a vacuum • Types of electromagnetic radiation are distinguished by their frequency, wavelength, and speed.
Dispersion – the separation of light into its individual wavelengths. Light waves bend as they pass through a prism; each wavelength is bent to a different degree. Dispersion of Light
Refraction of Light • Refraction – the bending of light waves caused by a change in speed. • The speed of light changes as light travels through different mediums • When light passes from one medium to another, the change in speed causes light to be refracted
Refractive Index • Like density, each substance has a unique refractive index; it is an intensive physical property • Refractive index = speed of light in a vacuum speed of light in a medium • The refractive index of water at 25oC is 1.333. • The refractive index of a substance depends on its density and it’s temperature; Remember that a substance’s density changes with temperature.
Analysis of Glass • The refractive index can be used to identify glass samples using the immersion method. • Glass samples are added to a liquid for which the refractive index can be adjusted. (usually by heating the liquid) • When the refractive index of the glass sample equals the refractive index for the liquid, the glass sample will seem to disappear from view.
Analysis of Glass • Becke line – a halo of light on the outside or inside border of a glass sample immersed in a transparent liquid. • When the Becke line disappears, the refractive index of the glass sample matches the liquid.
Analysis of Glass TeacherTube Videos - Refractive index of glass