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Most of the electricity in an LED becomes heat rather than light – about 70% heat and 30% light. [1] If this heat is not removed, the LEDs run at high temperatures, which not only lowers their efficiency, but also makes the LED less reliable, shortens its lifespan. Thus, thermal management of high power LEDs is a crucial area of the research ...
The produced light gets partially reflected back into the semiconductor, where it may be absorbed and turned into additional heat; this is usually one of the dominant causes of LED inefficiency. Often more than half of the emitted light is reflected back at the LED-package and package-air interfaces.
The actual phenomenon that is sometimes called heat lightning is simply cloud-to-ground lightning that occurs very far away, with thunder that dissipates before it reaches the observer. [2] At night, it is possible to see the flashes of lightning from very far distances, up to 100 miles (160 km), but the sound does not carry that far. [3]
Many cavers prefer this type of unfocused light as it improves peripheral vision in the complete dark. The reaction of carbide with water is exothermic and produces a fair amount of heat independent of the flame. In cold caves, carbide lamp users can use this heat to help stave off hypothermia. [8] Acetylene is produced by the reaction: [9]
Related: 300 Trivia Questions and Answers to Jumpstart Your Fun Game Night What Is Today's Strands Hint for the Theme: "Shape and Bake"? Today's Strands game deals with molds/shapes for a yummy treat.
Round bulbs, often tinted red to reduce visible light, provide infrared radiant heat suitable for warming of people or animals, but the power density available is low. The development of quartz halogen linear lamps allowed much higher power density up to 200 watts/inch of lamp (8 w/mm), useful for industrial heating, drying and processing ...
Cold weather could lead to a surprise when you start your car in the morning: The colder weather can trigger a warning light in your car. Your car's low tire pressure light may come on this week ...
Aim for seven to nine hours of sound sleep each night and establish a consistent bedtime routine. "Avoid caffeine close to bedtime or high-intensity exercise within three hours of sleeping," says ...