Biot-Savart Field of a Straight Wire Calculator implementation

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

t5-192

Effect

Computation or source lookup only

Input and validation requirements

The instrument breaks on the exact input r=0 because the formula divides by zero and should return an explicit rejection or undefined result. It is also vulnerable to a factor-of-100 error when a distance is entered without an explicit unit.

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": {
    "I": 5,
    "I_unit": "A",
    "r": 0.02,
    "r_unit": "m",
    "wire_axis": "+z",
    "current_direction": "+z",
    "observation_side": "+x"
  },
  "expected_outputs": {
    "B_magnitude_T": 0.00005,
    "direction": "+y"
  },
  "working": "B=(μ0 I)/(2πr)=[(4π×10^-7)(5)]/[2π(0.02)] = (20π×10^-7)/(0.04π) = 500×10^-7 = 5×10^-5 T. By the right-hand rule, +z current viewed from the +x side gives +y field."
}

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