(physics) The portion of the electromagnetic spectrum which is visible to the human eye.
Visible-spectrum Sentence Examples
rays not appearing in the visible spectrum - are absorbed and employed by these and other colourless bacteria.
The importance of his achievement may be judged from the fact that, while the visible spectrum includes rays having wave-lengths of from about o 4 p to 0.76, u, and no invisible heat-rays were known before 1881 having a wave-length greater than 1.8 µ, he detected rays having a wave-length of 5.3 A.
If suitable values are chosen for these constants, the formula can be made to represent the dispersion of ordinary transparent media within the visible spectrum very well, but when extended to the infra-red region it often departs considerably from the truth, and it fails altogether in cases of anomalous dispersion.
Defining oscillation as is usual in spectroscopic measurement by wave-length, the visible spectrum is found to extend from about 7700 to 3900 A.
The only way in which the secondary spectrum can be reduced still further is by the employment of three lenses of three different sorts of glass, by which arrangement the secondary spectrum has been reduced in the case of the Cooke photo visual objective to about I/loth part of the usual amount, if the whole region of the visible spectrum is taken into account.