Source: https://guthlabs.ai/docs/instruments/brewster-s-angle-calculator/implementation/

instrument implementation / implementation-contract

# Brewster's Angle Calculator implementation

A source-bound implementation contract for Brewster's Angle Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-162

**Effect**: Computation or source lookup only

## Input and validation requirements

The exact input n1=0 produces a division-by-zero undefined result. The instrument must reject it rather than returning a numeric angle. A second hazard is convention ambiguity: the formula gives the angle from the normal, while some interfaces may display the complementary angle from the surface.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "n1": 1,
    "n2": 1.5
  },
  "expected_outputs": {
    "thetaB_rad": 0.982793723,
    "thetaB_deg": 56.309932
  },
  "working": "1. Compute the index ratio: n2/n1 = 1.5/1.0 = 1.5. 2. Apply the formula: θB = atan(1.5) = 0.982793723 rad. 3. Convert to degrees: 0.982793723 × 180/π = 56.309932°."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/brewster-s-angle-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/brewster-s-angle-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/brewster-s-angle-calculator/qualification/>)

## 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`