Electron Spectroscopy Experiment

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In Transmission Electron Microscope, the electron beam is confined by the two condenser lenses which also control the brightness of the beam, passes the condenser aperture and “hits” the sample surface as shown in the Fig 3.5. The electrons that are elastically scattered consisted of the transmitted beams, which pass through the objective lens. The objective lens forms the image display. The apertures, the objective and selected area aperture are used to choose of the elastically scattered electrons and these will form the image on the microscope. Finally, the beam goes to the magnifying system that is consisted of three lenses. The first and second intermediate lenses which control the magnification of the image and the projector lens. The…show more content…
Actually UV-Vis is a subclass of spectroscopy that uses visible light and adjacent near ultraviolet ranges for the determination of the concentration and the characterization of dissolved substance. Again the absorption of light is a physical process in which the amount of absorbed light depends on concentration of the substance C, the thickness of the liquid layer d and a specific absorption coefficient α at a given wavelength λ. The phenomenon of light transmission through a sample can be described by the fraction of light at a specific wavelength λ that passes through the sample (Fig 3.7). If Io is the intensity of the incident light and I1 be the intensity of the transmitted light then the transmittance T can be expressed…show more content…
The principle absorption spectroscopy based on Lambert – Beer’s Law. According to Lambert’s law the fraction of the monochromatic light absorbed by a homogeneous medium is independent of the intensity of the incident light and each successive unit layer absorbs an equal fraction of the light incident on it. On the other hand Beer’s law states that the fraction of the incident light absorbed is proportional to the number of the absorbing molecules in the light path and will increases with increasing concentration or sample thickness. Finally, Lambert-Beer’s expressed

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