meter to detect and measure radiant energy (electromagnetic or acoustic)
A device that measures radiant energy.
an instrument designed for measuring the mechanical effect of radiant energy
Origin: [L. radius radius + -meter: cf. F. radiomtre.]
A radiometer is a device for measuring the radiant flux of electromagnetic radiation. Generally, the term radiometer denotes an infrared radiation detector, yet it also includes detectors operating on any electromagnetic wavelength. A common example is the Crookes radiometer, an early-model device wherein a rotor in a partial vacuum spins when exposed to light. A common myth is that the momentum of the absorbed light on the black faces makes the radiometer operate. If this were true however, the radiometer would spin away from the non-black faces, since the photons bouncing off those faces impart even more momentum than the photons absorbed on the black faces. Follow the link below for an in-depth explanation of the principles behind a Crookes radiometer. The Nichols radiometer operates on a different principle and is more sensitive than the Crookes type. A microwave radiometer operates in the microwave wavelengths. The radiometer contains argon gas to enable it to rotate. The MEMS radiometer, invented by Patrick Jankowiak, can operate on the principles of Nichols or Crooke and can operate over a wide spectrum of wavelength and particle energy levels.
The Standard Electrical Dictionary
An instrument consisting of four vanes poised on an axis so as to be free to rotate, and contained in a sealed glass vessel almost perfectly exhausted. The vanes of mica are blackened on one side. On exposure to light or a source of heat (ether waves) the vanes rotate. The rotation is due to the beating back and forth of air molecules from the surface of the vanes to the inner surface of the glass globe.
The numerical value of radiometer in Chaldean Numerology is: 8
The numerical value of radiometer in Pythagorean Numerology is: 9
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