Basically one can use phones as Colourimeter by Beer’s Law which is an equation that relates the attenuation of light to properties of a material. The law states the concentration of a chemical is directly proportional to the absorbance of a solution.
- Absorbance = - log ( Intensity / Intensity of 0 molar solution. )
We first get a number of data points of known molarity and it’s obserbance ( the more the data the result will be ) Then we plot concentration as a function of Absorbance and derive the equation of best fit line and use that equation to find unknown concentrations.
- Absorbance = m( concentration) + b
- Concentration = (Absorbance - b) / m