Physics

Hi, I am currently doing a project looking into the absorption of light and how to reduce this. I also want to look into where light goes. The aim of the project is to find which material and which way i use these materials is most effective at harnessing light over longer distances. I understand that light is absorbed by materials and the energy is represented as molecular vibrations. What i want to do is transfer the light over a long distance for example down a tube lined with tin foil however will the light fade over long distances? Also if i split this light into different directions will its brightness also reduce? I understand that if you did thi…

Interesting article in New Scientist (Australian printed edition 5 April page 36) by Prof. Michio Kaku - theoretical physics at City University of New York - and author of "Physics of the Impossible." He discusses what scientific and technological developments might occur in the future - which will happen soon, or later, and which are plain impossible. He points out that the history of science is full of luminaries that make lousy predictions. Examples are Lord Kelvin denying that heavier than air flight is possible, claiming that X-rays are a hoax, and that radio has no future. Ernest Rutherford denying that the A bomb will ever be possible. Prof. Kaku s…

Im a bit new to this and ive been asking this question to a few people but I havent had an answer yet. Can any one help? Im asking if any one can give me a definition for pure energy? Does it even exist? Thanks

Looking through my telescope (refracting) I note that right & left are reversed, why does a telescope do this and not binoculars?

I didn't know which category this fitted in, but you got the duty: When it’s hot. They say, “wear a hat”. To keep the heat off (No, not just the UV). When it’s cold, they say, “wear a hat”. “30% of your body heat is ‘lost’ via your head…” Isn’t this crazy talk? Your hot blooded brain isn’t going to conserve body heat because it’s got a hat on it? Isn’t putting a hat on, in summer, going to make you hotter? Given the above? My idea is that ‘hat’s have no net-effect at all except in extreme, extreme. Circumstances. Can a hat, at any time (not counting a blizzard), do any good?

Why doesn't dark matter collapse into a black hole? There's supposed to be these huge disks of dark matter in galaxies that only interact gravitationally -- so what prevents them from collapsing since gravity is only attractive?

Ok, so for this question, I have created an image: So, the only problem I have encountered is the fuel cell; more specifically, how do I get/make one. This is not supposed to power a car by the way, just charge a cell phone, or power an alarm clock. Something of that nature.... Thanks, Vlad

Anyone know the conversion from W/m2 to kcal/hr-m2 ?

Its the Ontario Association of Physics Teachers. They make contests for grade 11 students taking physics 11. The contest was today somewhere between morning to noon. If anyone else has taken the contest please discuss here(i need some answers now>) btw i can post the question sheet but im not really sure if im allow or not. Just in case one of you who took OAPT today wants to share some of your answers...please help, and do so =D here are previous questions:http://www.oapt.ca/grade_11_contest/past_exams.html its pretty interesting

I'm recently trying to pick up some knowledge about electrical circuits, and one concept that keeps coming up is the "electrical impedance". No matter how much I read about it, it doesn't seem to solidify in my head. Can anyone say in layman's words what it means? I have read the wikipedia, and some other articles, so I was hoping that someone could explain it to me without using mathematical terms. Is there any way I can see impedance with a simple experiment at home (using basic electric components: resistors, capacitors, (AC) power source, etc.)?

Why the anthropic principle and the fine tuning argument have become little more then a reality that slowly a huge gathering of religious types is occurring in physics. Both are little more then logical fallacies based on contemporary human thought that can be hotly debated. ON the basis or the face that they can be debated so easily should be the pointer to them being less then scientific but I want to get a little more in depth then that. It seems that many in academia and above would like to fit various pieces of scientific reality to fit some mold, such as the generation of the entire intelligent falling scheme. I would like to point out that many offspring first of a…

Hello guys, I'm struggling with these type of circuits. Here is my question. I have drawn a diagram in paint When the input AC voltage= 0 v the collector current is found to be 1.0 mA. The current gain of the amplifier is 200. There must be 0.7 V between B and E before current can flow from the collector to the emmiter. What is the resistance of Rb Well I know that Ai= Ic\Ib and I can find Ib but I don't know how to use this information. My understanding of series and parallel circuits is good but I don't know how this type of circuit works. If anyone can give me a detailed step by step of how this system works I'll be reallly really greatful

I'm having a test on this this week and well, I have hard time understanding this concept. #1: With pulleys, my teacher tried to explain that I can find the ideal mechanical advantage of the pulleys by counting the "number" of strands. Can anyone explain how I count the strands? Say in this website: http://www.phys.unsw.edu.au/~jw/blocks.html (i), (ii), (iii) and (iv), are the IMA 1 and 2 for first two? I don't know how to do the 3rd one and I think the last one is 6... Can anyone help me with this? It is so annoying! #2: Bicycles... Can anyone tell me how bicycle breaks down into simple machines?

Archimedes “displacement” eureka, I don’t get it. The story I know is this: Archimedes was asked by his king to find out if a ‘gold’ crown he had been gifted was really solid gold. Archimedes’ answer was ‘displacement’. How does the amount of water the crown displaces, indicate density? Couldn’t he just weigh it? I’m prepared to be embarrassed. But I don’t get it.

Hi, When I compare the reactions of fission to fusion, I notice that fusion produces more than ten times as many neutrons per unit energy. The neutrons in a fission reactor are absorbed by the shielding mass. The problem is that they are absorbed into the atoms of the shielding. The isotopes and even elements change under neutron bombardment, so that the shielding itself becomes too radioactive to work near. After 50 years they shut down the reactors and abandon them. If there are ten times as many neutrons produced by fusion, doesn't that mean a fusion reactor will burn-up its shielding in only a few years? Data Rider http://data-rider.org

I've been all over wikipedia reading about tesla's, webers, gauss, maxwells, oersteds, etc, and I suppose that if I really spent the time, I could have a deep understanding. I was kind of hoping there was a simple equation that could help me. Take the following: http://www.kjmagnetics.com/proddetail.asp?prod=B111 How can I figure out what size magnet of the same material it would take to demagnetize the one I linked?

Hello guys, I got a small question. It says circuit consists of three identical lamps connected to a battery with a switch as shown in the diagram. When the switch is closed what happens. I did this really quick on paint. It says that lamps C turns off because no current flows through it. But I don't get it. Shouldn't the current divide and each section get some current. Why is C getting no current when the switch is closed. Any help would be appreciated. Thanks

I am going into my junior year have about 60 credits and decided to change to physics. It's Applied Physics with a concentration in Engineering. I just added another year of school onto my plate, but I am willing to do it. Do you think it's a wise decision? I got a B in all four physics classes I've taken so far. I am having a hard time with Calculus 2, but I think I can pull it out. Any advice? Im not sure where I can even get a job, but I want to do what interests me. Thanks

how do you convert km/h to m/s?

Hi, recently I have made a Volta´s Battery. This is a simple device that consists on two different metals and a glass of water. Using this procces you can obtain a very little amount of energy. But with the time, the screw oxides because one metal gives electrons to make possible obtain energy. But I have a question, recently I read that you can obtain these electrons from the water instead from the screw. But I don´t know how do it.

1.To avoid a potential collision with wildlife crossing the road, the driver of a car travelling 105 Km/h fully applies the brakes to stop as quickly as possible. If the car stops 3.8 s after the brakes are applied, what is the braking distance? 2.A vehicle comes to a stop 10.0 s after the brakes are applied. While the brakes were applied, the vehicle travelled a distance of 75.0m. If the vehicles acceleration remained constant during the braking, what was the vehicles initial speed? 3.Based on a reaction time of 1.50 s and a braking rate of -5.85 m/s, the stopping distance of a vehicle travelling 90 Km/h would be? 4.A high performance car initially travelling…

If I have a power source that is giving a good amount of volts, but very little number of amperes... Can I recharge a battery? Or not? Or maybe the proccess will take more time?

Hi, I want to know if an electromagnet is affected by the voltage or voltage+current. I thought that if the Newman motor runs on voltage, maybe an electromagnet would need only voltage, instead of voltage + current. I use a homemade (screw and copper wire) electromagnet. Anybody knows?

Hypotherical Q: Lets say a spaceship A was travelling at .8c (C=speed of light) and space ship B was travelling at .8C too but in the opposite direction. So from the frame of reference A, doesn't it look like spaceship B is travelling at 1.6C? am i missing something here? EDIT: it was just a typo to type 1.8C. and why would it look like it is .9somethingc?

Hello guys:-), I have one more question. I'm not really sure that the answer to this question is current pathway anyway all the resitors are 100 ohms. Why is that when the witch is closed the voltage of resistor 1 is 15. Is it because when the switch is closed the current takes the path with least resistance. I checked about this least resistance thing in the internet and they say that it is not always the case. Any help would be appreciated. Thanks:-)