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The Hawthorne effect is a type of human behavior reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed. [1] [2] The effect was discovered in the context of research conducted at the Hawthorne Western Electric plant; however, some scholars think the descriptions are fictitious.
An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a filament that is heated until it glows. The filament is enclosed in a glass bulb that is either evacuated or filled with inert gas to protect the filament from oxidation. Electric current is supplied to the filament by terminals or wires ...
It can be adapted to similar equations e.g. F = ma, v = fλ, E = mcΔT, V = π r 2 h and τ = rF sinθ. When a variable with an exponent or in a function is covered, the corresponding inverse is applied to the remainder, i.e. = and = .
If light pressure were the cause of the rotation, then the better the vacuum in the bulb, the less air resistance to movement, and the faster the vanes should spin. In 1901, with a better vacuum pump, Pyotr Lebedev showed that in fact, the radiometer only works when there is low-pressure gas in the bulb, and the vanes stay motionless in a hard ...
Triboluminescence is a phenomenon in which light is generated when a material is mechanically pulled apart, ripped, scratched, crushed, or rubbed (see tribology). The phenomenon is not fully understood but appears in most cases to be caused by the separation and reunification of static electric charges , see also triboelectric effect .
1879: British physicist-chemist Joseph Swan independently developed an incandescent light bulb at the same time as American inventor Thomas Edison was independently working on his incandescent light bulb. [43] Swan's first successful electric light bulb and Edison's electric light bulb were both patented in 1879. [44]
Another example is incandescent light bulbs, which emit only around 10% of their energy as visible light and the remainder as infrared. A common thermal light source in history is the glowing solid particles in flames, but these also emit most of their radiation in the infrared and only a fraction in the visible spectrum.
For comparison, a conventional incandescent light bulb of 60–100 watts emits around 15 lm/W, and standard fluorescent lights emit up to 100 lm/W. As of 2012, Philips had achieved the following efficacies for each color. [8] The efficiency values show the physics – light power out per electrical power in.