Final answer:
In AAS, the monochromator is located after the sample compartment, allowing it to separate the specific wavelength of light emitted by the atoms in the flame.
Step-by-step explanation:
In AAS (Atomic Absorption Spectroscopy), the monochromator is located after the sample compartment, which contains the flame.
This is different from a UV-Visible absorption spectrophotometer where the monochromator is located before the sample compartment.
The reason for this difference is due to the principles of these two techniques.
In AAS, the monochromator is placed after the sample compartment so that it can separate the specific wavelength of light emitted by the atoms in the flame.
It allows only the desired wavelength to pass through and reach the detector, while blocking other unwanted wavelengths.
This helps in accurately measuring the absorption of light by the atoms in the sample.
In contrast, the monochromator in a UV-Visible absorption spectrophotometer is placed before the sample compartment.
This allows the monochromator to scan through different wavelengths of light before it reaches the sample.
The monochromator helps in selecting the desired wavelength for the analysis, and then the light passes through the sample compartment where the absorption of light by the sample is measured.