A report on Light and Electromagnetic radiation

A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.
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The electromagnetic spectrum, with the visible portion highlighted
Shows the relative wavelengths of the electromagnetic waves of three different colours of light (blue, green, and red) with a distance scale in micrometers along the x-axis.
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In electromagnetic radiation (such as microwaves from an antenna, shown here) the term "radiation" applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, so that the total radiation energy that crosses through an imaginary spherical surface is the same, no matter how far away from the antenna the spherical surface is drawn. Electromagnetic radiation thus includes the far field part of the electromagnetic field around a transmitter. A part of the "near-field" close to the transmitter, forms part of the changing electromagnetic field, but does not count as electromagnetic radiation.
Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily
Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This 3D animation shows a plane linearly polarized wave propagating from left to right. The electric and magnetic fields in such a wave are in-phase with each other, reaching minima and maxima together.
Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.
Representation of the electric field vector of a wave of circularly polarized electromagnetic radiation.
Hong Kong illuminated by colourful artificial lighting.
James Clerk Maxwell
Pierre Gassendi.
Electromagnetic spectrum with visible light highlighted
Christiaan Huygens.
Rough plot of Earth's atmospheric absorption and scattering (or opacity) of various wavelengths of electromagnetic radiation
Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.
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Light or visible light is electromagnetic radiation within the portion of the electromagnetic spectrum that is perceived by the human eye.

- Light

It includes radio waves, microwaves, infrared, (visible) light, ultraviolet, X-rays, and gamma rays.

- Electromagnetic radiation
A triangular prism dispersing a beam of white light. The longer wavelengths (red) and the shorter wavelengths (blue) are separated.

23 related topics with Alpha

Overall
Faraday holding a piece of glass of the type he used to demonstrate the effect of magnetism on polarization of light, c. 1857.

Faraday effect

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Physical magneto-optical phenomenon.

Physical magneto-optical phenomenon.

Faraday holding a piece of glass of the type he used to demonstrate the effect of magnetism on polarization of light, c. 1857.
GaAs-Faraday rotation spectrum

The Faraday effect causes a polarization rotation which is proportional to the projection of the magnetic field along the direction of the light propagation.

The theoretical basis of electromagnetic radiation (which includes visible light) was completed by James Clerk Maxwell in the 1860s.

The luminiferous aether: it was hypothesised that the Earth moves through a "medium" of aether that carries light

Luminiferous aether

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The luminiferous aether: it was hypothesised that the Earth moves through a "medium" of aether that carries light
The Michelson–Morley experiment compared the time for light to reflect from mirrors in two orthogonal directions.

Luminiferous aether or ether ("luminiferous", meaning "light-bearing") was the postulated medium for the propagation of light.

In contrast to the modern understanding that heat radiation and light are both electromagnetic radiation, Newton viewed heat and light as two different phenomena.

Intensity (physics)

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Power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy.

Power transferred per unit area, where the area is measured on the plane perpendicular to the direction of propagation of the energy.

Intensity is used most frequently with waves such as acoustic waves (sound) or electromagnetic waves such as light or radio waves, in which case the average power transfer over one period of the wave is used.