Which wavelengths are associated with visible light according to the material?

Which wavelengths are associated with visible light according to the material?

• A. 400 to 700 nanometers
• B. 700 to 400 nanometers
• C. 1,400 to 700 nanometers
• D. 1,000 to 2,000 nanometers

Answer: (B)

Visible light is the part of the spectrum that humans can see, roughly spanning from about 400 nanometers (the violet end) to about 700 nanometers (the red end). Some texts list this range in reverse order, as 700 to 400 nanometers, which describes the same set of wavelengths—the endpoints are the same, just written from high to low. That’s why this description matches the visible range. Wavelengths outside this band, such as around 1,000 to 2,000 nanometers or 1,400 nanometers, fall into the infrared region and are not visible to the eye.

Visible light is the part of the spectrum that humans can see, roughly spanning from about 400 nanometers (the violet end) to about 700 nanometers (the red end). Some texts list this range in reverse order, as 700 to 400 nanometers, which describes the same set of wavelengths—the endpoints are the same, just written from high to low. That’s why this description matches the visible range. Wavelengths outside this band, such as around 1,000 to 2,000 nanometers or 1,400 nanometers, fall into the infrared region and are not visible to the eye.