Six handheld laser pointers are sold with nominal wavelengths given in the product specifications: 405 nm, 450 nm, 520 nm, 590 nm, 630 nm, and 670 nm. Although all six beams appear bright to the unaided eye, their perceived colors differ noticeably.
Use the information provided to analyze how wavelength determines the human perception of color in the visible spectrum.
(a) List the six laser pointers in order of increasing wavelength.
(b) For each laser, state the approximate color that a typical human observer would perceive under normal viewing conditions.
(c) Describe, in prose, the physical relationship between wavelength and perceived color across the visible spectrum, and explain how this relationship justifies the order and color identifications you provided in parts (a) and (b).