The formula to calculate the absorbance (A) is:
\[ A = \epsilon \cdot c \cdot l \]
Where:
Let's say the molar absorption coefficient (ε) is 0.1 m²/mol, the concentration (c) is 0.5 mol/L, and the path length (l) is 1 m. Using the formula:
\[ A = 0.1 \cdot 0.5 \cdot 1 \]
We get:
\[ A = 0.05 \]
So, the absorbance is 0.05.