Thin Lens Equation Calculator

Inspectable records

Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Area

Physics — Kinematics/Projectiles/Orbits, Forces/Energy/Momentum, Rotational Dynamics, Gravitation, Oscillations/Waves, Optics, E&M Fields, Relativity, Quantum, Statistical Thermo

Tranche

tranche-5

Evidence ID

t5-114

Ledger rows

1

No ledger note is attached.

Review findings

The thin-lens equations and honest-label claim are appropriate, but the instrument needs an explicit sign convention, unit policy, input constraints, singularity behavior, and classification rules before it can receive PASS.

Formula and scope findings

• The formulas are standard only under an explicitly stated sign convention: f>0 for converging lenses, f<0 for diverging lenses, do>0 for a real object, and di>0 for a real image.
• The formulas do not specify the classification rules that convert the sign of di and m into real/virtual and upright/inverted outputs.
• The specification does not define behavior at the focal-plane boundary do=f, where the image is at infinity and finite di and m do not exist.

Unit assumptions

• f and do must use the same length unit before substitution; di is returned in that same unit.
• This review assumes the real-is-positive convention: converging f>0, diverging f<0, real object do>0, real image di>0.
• Under this convention, di>0 means real and di<0 means virtual; m<0 means inverted and m>0 means upright.
• The thin-lens and paraxial approximations apply, so object and image distances are measured from the lens's principal plane.

Boundary hardening

BREAK_CLAIMED · SELF_FLAGGED

The singular inputs do = f and do = 0 require explicit rejection or infinity handling, and the signed-distance convention is unspecified. Without validation and a documented sign convention, the calculator can produce undefined results or a different image type and magnification for the same physical setup.

Errata and corrections

No applied erratum is attached to this unique-name record.

Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

{
  "inputs": {
    "f": 50,
    "do": 300,
    "unit": "mm"
  },
  "expected_outputs": {
    "di": 60,
    "m": -0.2,
    "image_type": "real",
    "orientation": "inverted"
  },
  "working": "1/di = 1/f - 1/do = 1/50 - 1/300 = 6/300 - 1/300 = 5/300 = 1/60. Therefore di = 60 mm. m = -di/do = -60/300 = -0.2. Since di>0, the image is real. Since m<0, it is inverted."
}

Related workflows

No source-defined multi-instrument workflow membership is recorded.

Sources and evidence

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

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