What are some examples of light sources
Propagation of light
The light of the sun is created in the approximately 300km thick layer of the photosphere. Its temperature is around 5500 ° C and its density is very low at around 0.000 001g / cm³ (density air 0.001g / cm³).
Stars are very distant "suns" with surface temperatures between 3000 ° C (red glowing stars) and 25000 ° C (blue glowing stars). At night you can see many of them in the sky.
Meteors (shooting stars)
Meteors are small celestial bodies (stones, chunks of ice, etc.) that have entered the earth's closest area of attraction and are slowed down by the air when they penetrate the earth's atmosphere. They get so hot that they glow and sometimes become liquid and gaseous. Only a part of very large meteors therefore reaches the earth's surface as a solid, the liquefied and gasified part practically sinks to the ground atom by atom.
In the case of lightning, the luminous phenomena come about through electrical discharges that stimulate the air gas to glow in various ways in the lightning channel.
The northern lights are created when particles (mainly electrons and protons) coming from the sun, deflected by the earth's magnetic field, reach the earth's atmosphere near the poles and stimulate the air gas atoms to glow.
Embers / lava
All strongly heated bodies emit a "light" that is characteristic of the body's temperature. Less hot bodies radiate red, very hot bodies white.
Fire / flames
The heat that is released during a chemical combustion reaction creates light in the flame.
In the incandescent lamp, a wire is heated so much by electricity that it emits the light radiation characteristic of the heated body. The hotter the filament, the "whiter" the light.
More about incandescent lamps from Christoph Wallner
In fluorescent tubes, electrons that have been accelerated by the applied electrical voltage hit gas atoms in the tube and stimulate them to glow.
The glow lamp is the smallest form of the fluorescent tube.
Light emitting diode (LEDs)
In the case of light-emitting diodes, structures of the semiconductor are stimulated to glow directly at a semiconductor boundary layer.
Luminescent material absorbs light, electron beams or UV radiation and emits them again as light of a different color either immediately (fluorescent) or with a delay (phosphorescent). This is used, among other things, for fluorescent tubes, television screens, nocturnal clock faces, etc.
Female fireflies (approx. 2 mm long) and some other animals stimulate chemical reactions by emitting nitrogen, which make phosphorescent materials glow in order to attract the attention of males.
- How can peace last forever
- Why did Trump suspend aid to Ukraine
- What is a Sikh baptism
- Are ClickFunnels good 1
- Can I sell branded products on Rakuten
- Why is this symbol important
- Can someone think like a programmer
- Which question always has to be answered with yes
- Do restaurants need digital marketing
- What are the different types of INFPs
- Malaysians are looked down on in Malaysia
- Why do Somalis look white
- Describe the most expensive thing you own
- Is Hawaii expensive to visit
- What is opum from ADP
- How to scroll topics in Quora
- Why are the smart people so complacent
- Why is India's Jet Airways suspending operations
- Like white men, strong black women
- When is schizophrenia dangerous?
- What is the current Forex purchase rate?
- Walmart is the best
- What are the cons of government jobs
- What is 45 out of 1000
- What is the function expandtabs in Python
- Is USA a good place to emigrate?
- Do weight gain pills work
- How does light bend around corners
- How does Facebook get its sponsored ads
- What is Amazon Echo Spot
- 99 of the startups really fail
- How do I become a strong woman
- Can someone help me understand string theory
- What are some great quotes from Douglas Adams