3. Give the absorption law for monochromatic radiation. Which two variables in the law remain constant for this experiment? A=abC

Absorption law for monochromatic radiation is the Beer's Law.

A = εbC = abC

A = Absorbance of compound X, it has no units

ε = The molar absorptivity of X at the particular wavelength with units L/mol.cm = a

b = The optical path length of the sample X, measured in cm = b

C = Concentration of compound X in mol/L = C

From the source of the question, the concentration is made to to vary, to check the Absorbance at different concentrations. Hence, the two variables that are held constant for this exercise include the molar absorptivity (ε) and the path length (b).

Check Explanation to shed more light on this.

Explanation:

According to Beer's law, the absorbance A (for a monochromatic radiation beam) of a solution containing an absorbing compound Χ, is proportional to the concentration of compound X, and is given as

A = εbC

Where

A = Absorbance of compound X, it has no units

ε = The molar absorptivity of X at the particular wavelength with units L/mol.cm

b = The optical path length of the sample X, measured in cm.

C = Concentration of compound X in mol/L.

From the complete question obtained from online, this question is part of an experiment to measure the Absorbance of a particular com pound at different concentrations of that compound. The image of the experiment's handbook isn't attached to prevent answer deletion due to going against community guidelines.

But, from the formula for Absorbance of a compound, if the concentration of the compound is variable, it means the molar absorptivity and the path length must have been held constant.

Hope this Helps!!!