Explain the principle of spectrophotometer.
Answers
PRINCIPLE OF SPECTROPHOTOMETER
Spectrophotometer is based on the photometric technique which states that When a beam of incident light of intensity I0 passes through a solution, a part of the incident light is reflected (Ir), a part is absorbed (Ia) and rest of the light is transmitted (It)
Thus,
I0 = Ir + Ia + It
⇒ In photometers (colorimeter & spectrophotometer), (Ir) is eliminated because the measurement of (I0) and It is sufficient to determine the (Ia). For this purpose, the amount of light reflected (Ir) is kept constant by using cells that have identical properties. (I0) & (It) is then measured.
⇒ The mathematical relationship between the amount of light absorbed and the concentration of the substance can be shown by the two fundamental laws of photometry on which the Spectrophotometer is based.
Spectrophotometry is a method to measure how much a chemical substance absorbs light by measuring the intensity of light as a beam of light passes through sample solution. The basic principle is that each compound absorbs or transmits light over a certain range of wavelength.
Its Principle, Method and Applications. Spectroscopy is the measurement and interpretation of electromagnetic radiation which is absorbed or emitted by atoms of a sample. This absorption or emission happens when the atoms of the sample move from one energy state to another in the presence of light.