Beer–Lambert Law (Absorbance) Calculator mechanism

Model scope

NEEDS_REVIEW because the exact unit ambiguity is that no units are specified for ε, l, or c, so numerically identical inputs can yield different results depending on whether length is in cm, mm, or another unit and whether concentration is mol/L or another concentration unit. The formula itself is correct when units are compatible and the Beer–Lambert assumptions hold.

• The formula A=εlc is the standard Beer–Lambert relationship, but the claim that any three inputs are sufficient is incomplete without requiring the denominator in the rearranged formula to be nonzero.
• The specification does not define physical validity constraints: path length, concentration, and molar absorptivity should generally be positive, and absorbance should normally be nonnegative for the stated use.
• The specification does not state that the calculation applies at a specified wavelength under consistent measurement conditions, such as a homogeneous sample and appropriate baseline correction.

Units and conventions

• A is dimensionless.
• If l is in cm, c is in mol/L, and ε is in L·mol^-1·cm^-1, then A=εlc is dimensionally consistent.
• If l is supplied in mm, it must be converted to cm before using ε in L·mol^-1·cm^-1.
• The wavelength, solvent, temperature, and sample conditions are assumed fixed for the supplied ε.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "A": 0.6,
    "epsilon": 15000,
    "epsilon_units": "L mol^-1 cm^-1",
    "l": 1,
    "l_units": "cm",
    "c": null,
    "c_units": "mol L^-1"
  },
  "expected_outputs": {
    "c": 0.00004,
    "c_units": "mol L^-1"
  },
  "working": "c=A/(εl)=0.600/(15000×1)=0.600/15000=0.0000400 mol L^-1=4.00×10^-5 mol L^-1."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

The zero-path-length input makes the concentration calculation undefined. With the specified plain-arithmetic engine, an unchecked implementation can return Infinity rather than rejecting the input. Unit ambiguity can additionally produce a tenfold concentration error.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche5/tranche5-results.json
• BOUNDARY_HAZARD_CATALOG.json