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The theoretical-maximum efficacy at that wavelength is 525 lm/w, so the lamp has a luminous efficiency of 38.1%. Because the lamp is monochromatic, the luminous efficiency nearly matches the wall-plug efficiency of < 40%. [7] [8] Calculations for luminous efficiency become more complex for lamps that produce white light or a mixture of spectral ...
Flat-wick lamps have the lowest light output, center-draft round-wick lamps have three to four times the output of flat-wick lamps, and pressurized lamps have higher output yet; the range is from 8 to 100 lumens. A kerosene lamp producing 37 lumens for 4 hours per day for a month (120 hours) consumes about 3 litres (6.3 US pt; 5.3 imp pt) of ...
An oil lamp is a lamp used to produce light continuously for a period of time using an oil-based fuel source. The use of oil lamps began thousands of years ago and continues to this day, although their use is less common in modern times.
Every morning, I heat a pot of water to make a cup of pour over coffee. And every morning, I waste a precious 10 minutes fretting about the tea kettle on the stove.
Scalds can be more severe when steam impinges on the naked skin, because steam can reach higher temperatures than water, and it transfers latent heat by condensation. However, when clothes are soaked with hot water, the heat transfer is often of a longer duration, since the body part cannot be removed from the heat source as quickly.
This is a list of sources of light, the visible part of the electromagnetic spectrum.Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that ...
Drinking milk or consuming other dairy products does not increase mucus production. [345] As a result, they do not need to be avoided by those with the flu or cold congestion. However, milk and saliva in one's mouth mix to create a thick liquid that can briefly coat the mouth and throat. The sensation that lingers may be mistaken for increased ...
Hence, direct electric heating may now give a similar carbon footprint to gas- or oil-fired heating, but the cost remains higher, though cheaper off-peak tariffs can reduce this effect. To provide heat more efficiently, an electrically driven heat pump can raise the indoor temperature by extracting energy from the ground, the outside air, or ...