Search results
Results from the WOW.Com Content Network
Using longer wavelengths means less light energy is needed for the same number of photons and therefore for the same amount of photosynthesis. For actual sunlight, where only 45% of the light is in the photosynthetically active wavelength range, the theoretical maximum efficiency of solar energy conversion is approximately 11%.
The amount of energy carried by a photon of light is determined by its wavelength. In lumens, this energy is offset by the eye's sensitivity to the selected wavelengths. For example, a green laser pointer can have greater than 30 times the apparent brightness of a red pointer of the same power output.
They generate power by burning natural gas in a gas turbine and use residual heat to generate steam. At least 20% of the world's electricity is generated by natural gas. Water Energy is captured by a water turbine from the movement of water - from falling water, the rise and fall of tides or ocean thermal currents (see ocean thermal energy ...
Nuclear energy and renewable energy have reduced environmental costs by decreasing CO 2 emissions resulting from energy consumption. [42] There is a catastrophic risk potential if containment fails, [43] which in nuclear reactors can be brought about by overheated fuels melting and releasing large quantities of fission products into the ...
For each unit of energy produced, nuclear energy has caused far fewer accidental and pollution-related deaths than fossil fuels, and the historic fatality rate of nuclear is comparable to renewable sources. [35] Public opposition to nuclear energy often makes nuclear plants politically difficult to implement. [32]
The efficiency of a conventional steam–electric power plant, defined as energy produced by the plant divided by the heating value of the fuel consumed by it, is typically 33 to 48%, limited as all heat engines are by the laws of thermodynamics (See: Carnot cycle). The rest of the energy must leave the plant in the form of heat.
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial lighting. [1] [2] In a descriptive sense, the term light pollution refers to the effects of any poorly implemented lighting sources, during the day or night. Light pollution can be understood not only as a phenomenon resulting from a specific source or kind ...
The daily light integral (DLI) is the number of photosynthetically active photons (photons in the PAR range) accumulated in a square meter over the course of a day. It is a function of photosynthetic light intensity and duration (day length) and is usually expressed as moles of light (mol photons) per square meter (m −2) per day (d −1), or: mol·m −2 ·d −1.