# If a 10 mM solution of a biomolecule in a cuvette of path length 10 mm absorbs 90% of the incident light at 280 nm, the molar extinction coefficient of the biomolecule at this wavelength is _____________ M⁻¹cm⁻¹.

If a 10 mM solution of a biomolecule in a cuvette of path length 10 mm absorbs 90% of the incident light at 280 nm, the molar extinction coefficient of the biomolecule at this wavelength is _____________ M⁻¹cm⁻¹.

## Answer

**Answer:** 1042.59 M⁻¹cm⁻¹

**Explanation:**

Using Beer’s Law:

A = \epsilon \cdot c \cdot l

Where:

- A = \log \left(\frac{100}{10}\right) = 1
- c = 10 \times 10^{-3} \text{ M}
- l = 1 \text{ cm}