a Varian coded lamp will not register in a Thermo instrument. The electronic configuration of the data coding is also specific to each instrument manufacturer and not interchangeable i.e. ![]() The parameters may be overridden by the operator if desired to suit the specific requirements of the analysis. Data coded hollow cathode lamps incorporate a unique electronic configuration in the base or plug which the instrument recognizes and sets default operating conditions for the routine analysis of that element. Heraeus manufacture and supply a complete range of data coded hollow cathode lamps for Varian, Perkin Elmer and Thermo instruments. Whilst these parameters are generally suitable for a particular element, they may need fine tuning to suit the specific analysis being carried out. The instrument will set default conditions for these parameters on entry of the element. Manual setting up of lamp current, wavelength, slit width, gas conditions and burner height takes only a few moments and allows the operator to set the optimum conditions for each particular analysis, which can be stored and recalled when required. Standard lamps may also be used in computer controlled spectrophotometers which are designed to take coded lamps as these instruments normally have the facility to be set up manually. Borosilicate glass is used for wavelengths over 350 nm, and high quality quartz for shorter wavelengths.ģ7 mm hollow cathode lamps are suitable for most commercial atomic absorption instruments. The window material is selected to achieve the optimum transmission of the primary spectral lines of the cathode element. All cathode materials are selected from the highest purity available – usually 99.99 % or better – to ensure high spectral line intensity, stability and low noise with good analytical sensitivity. The Heraeus catalogue includes 70 single-element lamps in standard 37 mm (1.5 inch) and 50 mm (2 inch) diameters to fit almost any AA instrument. A) II and III B) I and IV C) I and III D) II and IV E) None of these statements explains this phenomenon.The Heraeus hollow cathode lamp product range comprises 70 single-element lamps and more than 120 multi-element lamps of the most varied designs to cover almost all appliances. IV As temperature decreases there is a decrease in emission intensity resulting from a decrease in the excited state population the apparent concentration is less than the actual concentration. III As temperature increases there is a decrease in emission intensity resulting from a decrease in the excited state population the apparent concentration is less than the actual concentration. ![]() II As temperature decreases there is a decrease in emission intensity resulting from an increase in the excited state population the apparent concentration is greater than the actual concentration. Which of the following statements explain this phenomenon? I As temperature increases there is an increase in emission intensity resulting from an increase in the excited state population the apparent concentration is greater than the actual concentration. Fluctuations in flame temperature affect the reproducibility of atomic emission experiments more so than atomic absorbance experiments.
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