Ultraviolet Light

Question: How do the wavelength of ultraviolet compares to a violet light? need the answer by 10 tonight :) Insects can see a color called ultraviolet. How do you think the wavelenght of ultraviolet light compares to that of violet light?

Answer: the wavelength of ultraviolet light is smaller/shorter than that of violet light

Question: At what intensity will ultraviolet light start killing mold, and how long do you need to have it on the spot? If you have an ultraviolet light with an intensity of 16,000 micro watts per centimeter squared, at 365 nm, how long will it take to kill mold and mildew in the bathroom or shower? Could you hold it on the area for 30 seconds, and the mold and mildew would be dead? I didn't realize that UV rays could kill germs and other bacteria till recently. I would like to know more about it.

Answer: One ultraviolet [UV] lamp of at least 10,000 uwats per second of exposure can kill almost all biological contaminants in the air EXCEPT for mold, which can take as high as 330,000 uwats per second of exposure, especially for the dangerous and commonly-found indoor mold Aspergillus Niger. To effectively kill mold with UV inside a heating/air conditioning system, you would need to have your heating/cooling contractor construct in the return air duct a kill box containing mirror-like surfaces to get a multiplication of killing power through the bouncing effect of the rays off the mirrors. The kill box would need at least a dozen or more UV lights with a power of at least 20,000 uwats each. That many lights, plus the bounce factor off the mirrors, would be strong enough in killing. In addition, you would need to have an access panel into the kill box to frequently dust off the bulbs which will become dust-laden and thus lose their effectiveness unless you have a really effectively and frequently replaced hepa filter system to clean incoming air into the return air duct. Just as effective as a UV killing box [and much easier and less expensive to install and maintain] would be to install a mass media [e.g., 4 to 6 inches thick] hepa filter in the return air duct. Get a mass media filter that can be washed, rather than replaced. Use an inexpensive, disposable pre-filter to do initial dirt and mold removal prior to the air entering the expensive mass media hepa filter. In addition to the mass media filter, you could also install an electronic air cleaner into your return air duct. If you install an electronic air cleaner and/or mass media filter, you may need to upgrade the size of your ventilating fan and motor to overcome the greater resistance to airflow caused by the air cleaner and/or mass media filter. Alternatively, learn the 25 steps for safe and effective

Question: What effect would ultraviolet light have on a reaction between methane and chlorine? What effect would ultraviolet light have on a reaction between methane and chlorine? Does anyone know the answer to this question, and can you also explain why it happens

Answer: This page should explain it clearly www.chemguide.co.uk/mechanisms /freerad/ch4andcl2tt.html

Question: What is the thinnest film that will highly reflect near-ultraviolet light of wavelength 350 nm? A thin film with index of refraction n-film = 1.38 is used to coat a lens, which has n-lens = 1.50. What is the thinnest film that will highly reflect near-ultraviolet light of wavelength 350 nm? What is the thinnest film that will minimize reflection of 700 nm light?

Answer: AuAg will help as well as aluminite. Light is a frequency wave, you will not get a perfect answer until you better understand Gauss

Question: What is the difference between visible,infared, and ultraviolet light.? In school were doing a chapter on astronmy, the section were in talks about visible,infared, and ultraviolet light nd i was wonderin what was the difference between these different forms of light. Best answer 10 points. Thanks 4 ur help =]

Answer: infrared - just below in frequency what your eyes can detect visible - a narrow band that our eye is sensitive to. Some animals have a slightly different range. ultraviolet - just above what your eye can detect. The terms are not interchangeable. They are historical - they were given before it was understood that they are all the same thing. It is part of the wave/particle duality - those bands that seemed like waves were called waves. Radio waves, microwaves. Radiation is clear in that infrared results in heating of an object or radiate from a heated object, and ultraviolet burns. The rays were called such because they seemed to act like particles - the shorter the wavelength the more particle like it seems to become. Diffraction was minimal. Gamma rays and cosmic rays were considered to be similar, when we know today that cosmic rays are not EM at all, but are high energy protons. These names stuck with us.

Question: Why isn't the recirculated air on airplanes passed through ultraviolet light to sterilize it and kill germs? Simply passing the air through ultraviolet light would kill germs and prevent the spread of illnesses on airplanes. This could help prevent the spread of epidemics, such as swine flu. It seems simple and inexpensive. Why isn't it done?

Answer: doyo

Question: How did scientists find out that bees can see ultraviolet light? How did scientists find out that bees can see ultraviolet light? I need to know this for a report. Please help if you can. Thanks a bunch.

Answer: There are two ways actually. The eyes of bees can be analyzed and a probe attached to record electrical activity in the nerves when ultraviolet light is sent in the eye. But more classically, it was very early noticed that bees can orient themselves relative to the sun, even when the sky is overcast, and that only UV light penetrates the clouds. Moreover, bees were known to be able to recognize a flower's structure despite them appearing uniform color to us (but not to a bee); see link for an example of that.

Question: What's the best camera to see ultraviolet light with? What's the best camera to see ultraviolet light with? I want to take pictures of minerals and stuff. I want to be able to see live and also take pictures.

Answer: I searched and couldn't find an actual camera that does that. You can buy a camera that has a lens replacement option and also sells a U.V. lens.

Question: What would the sky look like if we could see infrared and ultraviolet light? If we could see infrared and ultraviolet light would the sky still be blue?

Answer: Looking up at the sky during the day would hurt like hell.

Question: Does ultraviolet light affect our environment? Heres the question How does ultraviolet light (UV)effect the environment? Its something we're doing in school and I did some researching on it but I wasn't able to find anything. So if you have any ideas for the question even if you're not sure it would be greatly appreaciated. I would love to have an answer by tonight. Thanks!

Answer: Some plankton species are very UV sensitive. The light kills them almost immediately. Since plankton form the basis of many aquatic food chains, the removal of plankton from the food chain can destroy the whole ecosystem.

Question: Is it possible to turn some sunlight into electricity and use it for ultraviolet light? I am researching about UV lightbulbs in water purifiers, those use ultraviolet light and since the sun has ultraviolet light just wondering if it's possible to make them more efficient and somehow incoroprate the sun into treating the water. Can we somehow store ultraviolet light from the sun?

Answer: PV cell running a UV lamp. Or PV to Battery to UV lamp. You lose energy at each conversion though.

Question: What are x-rays, ultraviolet light, & radioactive substances that can change the chemical nature of DNA class? i need this by tomorrow , perfered by to night , science question. What are x-rays, ultraviolet light, and radioactive substances that can change the chemical nature of DNA classified as?

Answer: mutagens =)

Question: Should I remove my ultraviolet light from my koi pond in the winter? If so, at about what water temperature? I live in South Carolina and have an ultraviolet light in my koi pond skimmer to keep the water clear in the summer months. Would it be wise to removed it in the winter so it will perhaps last longer? Also, should I turn off my water fall in the winter? Or at minimum not run it 24 hours a day? I have about 3 dozen goldfish and four koi. The water at the deepest part is about 30 inches.

Answer: I suggest that you keep everything running. The water fall is important for maintaining the oxygen level in water - you don't want your fish to die.

Question: wavelengths of infrared and ultraviolet light? anyone happen to know the approximate wavelengths of infrared and ultraviolet light? and if there's a special way of finding out, maybe you could let me know that too? thanks bunches!

Answer: IR goes all the way from 750 nm up to 1 mm. UV is about 1 nm to 400 nm. I can't really think of a particular way to memorize them. I just work with them all the time.

Question: Which has the greatest energy- a photon of infrared light, of visible light, or a ultraviolet light? I am so lost! anything would help! thanks Which has the greatest energy- a photon of infrared light, of visible light, or a ultraviolet light? An electron de-excites from the fourth quantum level in the diagram above to the third and then directly to the ground state. Two photons are emitted. How does the sum of their frequencies compare with the frequency of the single photon that would be emitted by de-excitation from the fourth level directly to the ground state?

Answer: Well, the energy of a photon is directly proportional to its frequency. The greater the frequency, the greater the energy. E = hf Ultraviolet light has a higher frequency than visible which has a higher frequency than infrared light. As for the de-exciting electrons, conservation of energy is clearly important here. The sum of the energies of the two photons in the two step movement from level four to ground is the same as the energy of one photon emitted going directly to ground.

Question: How would you list these in order of increasing frequency: Microwave, Gamma, Green light and Ultraviolet light? How would you list these in order of increasing frequency (So least amount is first): Microwave, Gamma ray, Green light and Ultraviolet light

Answer: microwave, green light, UV, gamma.

Question: Does synthetic rubies glow pink under ultraviolet light? I have a ring with a red stone (and it's not garnet) and i don't know if it's a ruby. But i know that real rubies does glow pink under ultraviolet light, and the stone in the ring does glow pink under ultraviolet light. So i wanted to know if synthetic rubies also glow pink under ultraviolet light. Could the stone in the ring be a real ruby?

Answer: Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves, striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin. So, yes, they'd glow like a 'real' ruby.

Question: A clean iron surface is illuminated by ultraviolet light. No photoelectrons are ejected until the wavelength o? A clean iron surface is illuminated by ultraviolet light. No photoelectrons are ejected until the wavelength of the incident UV light falls below 282 nm. (a) What is the work function (in eV) of the metal? (b) What is the maximum kinetic energy for electrons ejected by incident light of wavelength 130 nm?

Answer: Work function of metal W = hc/L, h=planck's constant c=speed of light in vacuum L=Wavelength Let L0= threshold wavelength =282nm and L1=130nm work function W= hc/(L0xe) =(6.63x10^-34)x (3 x 10^8)/(282x10^-9 x 1.6x10^-19) =4.4eV Maximum kinetic energy of emitted electrons = Energy incident - work function = hc/(L1xe) - W =(6.63x10^-34)x (3 x 10^8)/(130x10^-9 x 1.6x10^-19) - 4.4 =9.56 - 4.4 =5.16eV

Question: It is possible for an atom to absorb a photon of visible light and emit photons of ultraviolet light? The full question is: In the process of fluorescence, an atom absorbs a photon of ultraviolet light and emits two or more photons of visible light. Is the reverse process possible? That is, it is possible for an atom to absorb a photon of visible light and emit photons of ultraviolet light? It would be helpful if someone could answer this as soon as possible. Thanks. Really appreciate it.

Answer: Yes.

Question: When the ultraviolet light from hot stars in very distant galaxies finally reaches us, it arrives at Earth in? X rays. slightly more energetic ultraviolet light. visible light. I think it may be visible light? Just need some confirmation. Thanks!

Answer: The redshift of the receding galaxy will shift the ultraviolet towards a longer wavelength. As the other two options have a shorter wavelength than UV the answer must be visible light.