Wednesday, March 26, 2014

SPECTROPHOTOMETER?

WHAT IS A SPECTROPHOTOMETER?

Spectrophotometer: Instrument used to measure the intensity of wavelengths in a spectrum of light compared with the intensity of light from a standard source. II Device for measuring the brightness of the various portions of spectra.

**WHAT IS SPECTROSCOPY?

Spectroscopy: In physics and physical chemistry, the study of spectra . The basis of spectroscopy is that each chemical element has its own characteristic spectrum.

***WHAT IS SPECTROPHOTOMETRY?

Branch of spectroscopy that deals with measurement of the radiant energy transmitted or reflected by a body as a function of the wavelength.

**WHAT IS SPECTRUM?

Spectrum: Rainbow like series of colors, in the order violet, blue, green, yellow, orange, and red, produced by splitting a composite light, such as white light, into its component colors.

* WHAT IS UV-VIS SPECTROSCOPY?

Ultraviolet-Visible spectroscopy or Ultraviolet-Visible spectrophotometry (UV/VIS) involves the spectroscopy of photons (spectrophotometry). It uses light in the visible and adjacent near ultraviolet (UV) and near infrared (NIR) ranges. In this region of energy space molecules undergo electronic transitions. The method is used in a quantitative way to determine concentrations of an absorbing 
species in solution, using the Beer-Lambert law:
where A is the measured absorbance, I0 is the intensity of the incident light at a given wavelength, I is the transmitted intensity, L the length of the cell, and c the concentration of the absorbing species. For each species and wavelength, ε is a constant known as the extinction coefficient.

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