ft⁻¹
per foot
Wavenumberexact by definition
The reciprocal foot is exactly 1/0.3048 m⁻¹, about 3.281 m⁻¹. It appears as an attenuation or decay constant in American engineering practice, wherever an exponential falls off over a distance stated in feet.
| 1 ft⁻¹ | 3.2808399 m⁻¹ |