Lights Definition and 161 Threads

Hi there, I've got a few questions about light that I'm hoping someone can help me with. 1. If the properties of energy and mass are interchangeable, then if some particle or wave possesses charge or energy then it must also have mass. Whether a photon is acting as a particle or a wave it...

I have a single lighting switch at home which controls two sets of light separately, but I have no idea how it works. Here's what the single switch does when flipped on-and-off quickly, On -> Light A turns on Off -> A turns off On -> Light B turns on Off -> B turns off On -> Light A and...

1.Marzena 2.ZapperZ 3.Equate http://img196.imageshack.us/img196/6771/bellagio.jpg 4.Signerror 5.MattRSK 6.Turbo-1 7.Galatea 8.Andre 9.Matthyaouw 10.Borek Contest Thread

Night lights[/color][/size] Photos at night, with things that are light. Interpret as creatively as you like. [SIZE="4"]Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're...

Homework Statement The strobe lights on top of two tall radio towers both have a period of about 1.00 s. When turned on simultaneously, a keen observer notes that during an 813 s interval, the lights gradually fall out of synchronization and then come back into flashing synchronously. What is...

My physics master at school (1970s) said that if you hold your hand in front of your eye whilst looking at a bright light, you can see lines appear in the tiny gaps between the fingers. He said that though some people thought this was slit diffraction, they were mistaken, the effect actually...

Is this a kind of northern lights? http://spaceweather.com/submissions/large_image_popup.php?image_name=Aigar-Truhin-LightPillar_0854_1230501854.jpg

I recently bought some LED light bulbs, made by Lights Of America, at our local Ace hardware store. Lights of America part number is 2026LED-30k and 2026LED-65k. So here are some of the claims written on the packaging: Uses 1.5W Replaces 40W bulb 90% more efficient than incandescent and...

An instrument can detect 9450 photons of light of wavelength of 8.065 × 10^-8 m. What is the minimum amount of energy in J to which the instrument is sensitive? Express answer in scientific notation.. i have tried to use the e = (planck's constant) ( speed of light ) / (wavelenghth) but i am...

By definition, are all mercury-vapor lights NOT incandescent lights? In practice, are mercury vapor lights ever incandescent lights? Are most street lights in the United States incandescent lights or mercury-vapor lights or sodium vapor lights or some other type of lights?

I know that the streets of London were illuminated by gas lights in the 1880s. The gas that powered the gas lights of London was coal gas. How was the chemical energy of coal gas transferred into light energy to light up the lamps?

http://www.nytimes.com/2008/07/25/science/space/25aurora.html?hp" This is pretty suprising to me and I don't quite understand how the sequence could play out in this way. Regardless, it is a pretty interesting piece. Medline

I want know that With Light Balancing Filters we can limit lights more than 55"centigrade ? I want a filter that EJECT further lights than 55"centigrade and only allow to <55"centigrade lights ! (i have a special vegetable that need a lot of heat ; But lights more than 55"centigrade can...

Hi, Got into a discussion at School today about reducing energy consumption at home in order to save the planet. I asked a question that stumped my Physics teacher. If I do turn off my lights and TV when I'm not in the room surely the fossils fuel would have already been burn and the...

I was wondering, I have heard that watching a blinking light can give you a head ack and a seizure. Why does that happen because our computer screens and tvs, are just blinking lights. They blink at about 60-80 times a second.

I can't stand them! Whenever I'm exposed to them I end up getting headaches and start feeling as if my eyes weighed a ton. But in a world in which classes and workplaces are dominated by these horrific conceptions, what can a poor fellow like myself do?

hey guys, i could as easily post this in an automotive type forum but I'm not a member of any! no specific car knowledge nescessary! Here is the problem Where I'm working now, there are two jeeps and one Car type trailer jeep 1 operates all the lights on the trailer successfully jeep 2...

How long at least must I turn off my fluorescent lights to save energy?

In the cellar you have three light switches, one of which turns the light on in the attic. You can only go upstairs once to check the light in the attic. Which switch turns on the light?

Hum... was this a difficult contest at this time of the year? Or was it just difficult to get pictures of lights? In any case, we have a small but excellent set of pictures for this contest. Please vote for the picture that best shows holiday lights. 1. glondor 2. ZapperZ...

[FONT="Comic Sans MS"]Holiday Lights The theme this week is self-explanatory. Your pictures must be on lights and lighting decorations during the holidays. This holiday is not confined only to the Christmas/New Year season. Zz. [SIZE="4"]Contest Rules: 1. Any digital photo or...

Hi everybody First, apologies if this has been answered somewhere else, haven't found it. If so, just point me towards it. Second, I don't know if this is the right place for this question, but I hope so. Third, I should now get on to the question. What I have been wondering about...

Hi all, I was hoping someone more knowledgeable about aquariums and specifically aquarium plants could help me out here. I have a 10 gallon aquarium that has two incandescent bulbs in the hood. I went to the pet store to get a plant for it, and they tell me that I should get one of those (14W)...

Silly "ecology action": a collective of ecologist organisations in France wanted everybody to switch off lights between 19:55 and 20:00, in order to "give a strong signal" to politicians that one is serious concerning measures against climate change. Especially in France where about 80% of...

I have to just throw this one out and see what comes. I have no idea if this is credible, but there are claims that local news agencies in Peru are reporting that earthquake lights were seen before and after the recent quake. There are a couple of videos included in the report...

sorry if this is the wrong section...i really don't know where to put it. well the other night i was trying to fall asleep in my room, and it was completely dark, or close to it. and i saw this weird glow, so i grabbed out, and pulled my flouescent lightbulb near me. I would touch it and it...

I want to explain physics at how can civil defense Change traffic lights from red to green ?

It hits me every time that I replace one in the house during the nine months of the year that we run the heater. I would imagine that the energy required to make one is significantly higher than for an incandescent bulb. And they don't seem to last as long as they used to. It makes me wonder...

Today I was looking around in the local hardware store in the electrical section for some lighting. I have a small building (20 x 30) that I want to light. In the cold months of the year it is not likely it will be heated very warm and florescent lighting is out of the question because of...

Xmas lights that is, it seem they go up earlier every year, any way i suppose most of you are looking forward to a nice holiday, not for me though, i only get xmas day of and quite often have more work to do :cry: Any ways up is there one thing you truly want for xmas, apart from good will...

I have wanted to do this for a while but cringe when I see the cost of the commercial systems. I want to be able to make lights flash in sync with mp3s on a computer but do not want to spend a lot of money. I know there are visualizations incorporated into Winamp, Windows Media Player, etc...

I'm trying to build a lighting system that's very small and have been experimenting with designs. I bought these things at the local Electronics Surplus, and I think, if I can get them to work, they'll do exactly what I need. Unfortunately, they couldn't provide any information about them at...

Hello. Does anyone here use and LED light for their desk? I am a college student and spend a lot of time at my desk reading. I get pretty bad eye strain from reading so much. I am thinking about getting one of these LED lamps. Also, does anyone use any other type of lamp that is better...

I am hearing mutterings over the radio that parts of uk may be turning off the street lights in the early hours, Essex was mentioned, hang on now i hear 11 to 5, cool or not?

hi, wish to ask, if experiment like below image : http://img168.imageshack.us/img168/4417/image28ei.png would the bulb lights for a "moment or X milisecond?" once we touch the wire B to the bulb? assume the wire B is a long long wire (just wire) wire A already attached to positive...

Maybe this has been posted before but anyway Im considering installing 24v aircraft landing lights on my jeep wrangler. (for off-road use.) What i would need to fabricate to make this work. I figure they will light up but i want them bright like they are supposed to be.

Hi, I have allways loved the look of the northern lights, but have never quite understood what actually causes them! :smile: Could anyone possibly explain it to me? :confused: Thanx

http://www.ctv.ca/servlet/ArticleNews/story/CTVNews/20060126/octopus_bc_060126/20060126?hub=Canada The ROV was seen smoking afterwards. :biggrin:

From the lights point of reference is it traveling infinitly fast? is it's travel instantaneous?

So I was reading The Art of Electronics and behold, the power went out.* And then I tried reading by candlelight**, but my eyes began to hurt. And the wax was creating a mess. Then I realized I could get onto PF using my notebook, with its fully-charged lithium ion batteries, but then - alas! -...

http://www.ebaumsworld.com/videos/xmaslights.html freaken awesome though!

My family just bought a bunch of fluorescent light bulbs for the house. I was just wondering if they are bad for my eyes, and should I allow for them to be in my room. Currently I have 4 regular incandescent light bulbs in my room. Are there only benefits with fluorescent light bulbs, and is...

I read in a science question/answer book that it is takes as much energy to turn on a fluorescent light as it doesn to run it for 1 hour. So if this is true, it would mean that if you plan on using the light again within an hour, it is more efficient to leave it on, rather than turning it off...

Circuit Help! Help! I am trying to design thsi circuit for some friends, however, having the 2 light bulbs in the circuit seem to "eat" all of the power, cuasing the laser to be VERY dim. Isn't there an electronic component taht i can jump across the light bulbs that will allow them to stay...

I need some help with a formula, I am constructing some aids for a class room demonstration on basic electricity. I am using lights to demonstrate series and parallel cicuits, also trying to explain some of the basic laws. My question, If I hook three 25 watt bulbs in series with a supply...

I was wondering how flourescant lights work, and how they eventually wear out. I'm not sure, but it seems that you just have halogen gas inside the glass tube, you pump some electricity into the gas, it excites the atoms and they give off light as their electrons go from higher energy levels...

1. In older houses, when a refrigerator starts up, the lights may dim briefly. When an electric heater is turned on, the lights may stay dimmed as long as it is on. Explain the difference. 2. Explain what is meant by the statement "a motor acts as a motor and generator at the same time." Can...

Hello, I'm having some difficulty in a physics question. The question is: To save fuel, some truck drivers try to maintain a constant speed when possible. A truck traveling at 81.0 km/h approaches a car stopped at the red light. When the truck is 94.6 meters from the car the light turns...

Why the stop lights at the back of cars are red ? Some say because red light is visible from far distances. If that's true, is any relation between this property of red light and its wave length ?

Hi, i have this question wrong in my intro statistics class and I'm wonder if someone could help me understand why. Thanks in advance. Heres the question: "A string of christmas lights contains 4 bulbs. The lights are wired in a series, so that if one fails, the whole sting would go dark...