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Each photoreceptor absorbs light according to its spectral sensitivity (absorptance), which is determined by the photoreceptor proteins expressed in that cell. Humans have three classes of cones (L, M, S) that each differ in spectral sensitivity and 'prefer' photons of different wavelengths (see graph). For example, the peak wavelength of the S ...
Exposure to ELF waves can induce an electric current. Because the human body is conductive, electric currents and resulting voltages differences typically accumulate on the skin but do not reach interior tissues. [22] People can start to perceive high-voltage charges as tingling when hair or clothing in contact with the skin stands up or ...
Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields. In a vacuum, electromagnetic waves travel at the speed of light, commonly denoted c. The frequency of the wave's oscillation determines its wavelength in the electromagnetic spectrum.
The light that excites the human visual system is a very small portion of the electromagnetic spectrum. A rainbow shows the optical (visible) part of the electromagnetic spectrum; infrared (if it could be seen) would be located just beyond the red side of the rainbow whilst ultraviolet would appear just beyond the opposite violet end.
Light sensitivity or photosensitivity refers to a notable or increased reactivity to light. Apart from vision , human beings have many physiological and psychological responses to light. In rare individuals an atypical response may result in serious discomfort, disease, or injury.
The antennas contained in mobile phones, including smartphones, emit radiofrequency (RF) radiation (non-ionizing "radio waves" such as microwaves); the parts of the head or body nearest to the antenna can absorb this energy and convert it to heat or to synchronised molecular vibrations (the term 'heat', properly applies only to disordered molecular motion).
Blue light, a type of high-energy light, is part of the visible light spectrum. High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.
By recording the attenuation of light for various wavelengths, an absorption spectrum can be obtained. In physics , absorption of electromagnetic radiation is how matter (typically electrons bound in atoms ) takes up a photon 's energy —and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy ).