The human eye can typically see frequencies in the approximate range of 400–790 terahertz.
The ability of the human eye to perceive light is limited to a specific portion of the electromagnetic spectrum known as the visible light spectrum. This spectrum is characterized by both wavelength and frequency, which are inversely related.
According to scientific understanding, a typical human eye responds to light with wavelengths ranging from approximately 380 to 750 nanometers. When converted into frequency, this corresponds to a band in the vicinity of 400–790 terahertz (THz). This narrow band of frequencies is what we perceive as visible light, encompassing all the colors of the rainbow.
Understanding Visible Light Characteristics
The perception of different colors is directly tied to the frequency (and thus wavelength) of the light. For instance:
- Higher frequencies (shorter wavelengths) near the 790 THz end of the spectrum are perceived as violet and blue.
- Lower frequencies (longer wavelengths) near the 400 THz end are perceived as red.
Key Characteristics of Human Vision's Frequency Range
| Characteristic | Wavelength Range (Typical) | Frequency Range (Typical) |
|---|---|---|
| Visible Light | 380–750 nanometers (nm) | 400–790 terahertz (THz) |
- Sensitivity Variation: While 400-790 THz defines the visible range, the human eye is not equally sensitive across this entire band. It is most sensitive to green-yellow light, which falls roughly in the middle of this frequency range.
- Individual Differences: The exact limits of visible frequencies can vary slightly from person to person, and can also be affected by age and specific eye conditions. However, the 400-790 THz range represents the typical boundaries for most individuals.
- Beyond Visible: Frequencies below 400 THz (e.g., infrared) and above 790 THz (e.g., ultraviolet) are imperceptible to the naked human eye, even though they are part of the broader electromagnetic spectrum.
This precise frequency range is crucial for our ability to navigate and interact with the world, forming the basis of color perception and visual communication.
