Recent content by bsimmo

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    Basic optics (GCSEs in 3 days, please help)

    In the diagram you give (first post) it is refracted, you just cannot see it clearly, because it's not by a lot.
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    What is the controversy- current and resistance

    If you really want to learn, go and do it... Get yourself some batteries (not mians power supplies), a couple of resistor and voltmeter and ammeter. Have a play and see what you get. That should answer your question...
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    Light problem

    Had a quick think and a look and this may shed more light on it. http://en.wikipedia.org/wiki/Retinal and related references.
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    Light problem

    frequency is cycles per second.... number of hits of that wavelength in a second 'rate it is hit at' Has this been thoroughly explored experimentally in different situations and different media? No idea, but I would have thought it may be hard to determine. The media in front of the...
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    Laser Combination

    808nm should not be visible, other than as a very dim glow at the target. If it is just a diode without a collimating lens then yes you will (depending on your area/neatness requirements, look at the divergence of 12/40 degrees* (vert/horiz probably). You may be able to focus with this as...
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    Light problem

    Shooting star, to be fair since the light has to travel through the 'eye bits' to get to the photoreceptors the wavelength will be shifting around as it goes through the different mediums (speed of light will change). Though from my understanding the photoreceptors responds to the length and...
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    What is the controversy- current and resistance

    It is just two cells (power supplies) in parallel to a resistor of value R The talk about little r confuses things, so just say in the ideal case. Since this is intro physics and a very basic circuit. Two cells in series (say 2x1.5V, 500mAh types) gives you what current and what voltage...
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    Angle of refraction

    I was going to add the link to the double but didn't know if I should do that.. https://www.physicsforums.com/showthread.php?t=205646 I guess it should be cross-post and not double post.
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    Angle of refraction

    double post...
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    Light problem

    It would change colour if it moved outside that colour range.... though 750nm should really be classed as infra-red. You should know you answer is in the right range when it fall in the red spectrum ;) If you get 400nm you're going wrong somewhere ;) I think the angles are suppose to be...
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    Inteference fringes

    Successive minima happen when you move the film+substrate along the perpendicular. iirc since a phase change occurs on the top surface, for destructive; Using 2ndcosΘ'=mλ n being the refractive index of the thin film d being the thinkness you are looking for Θ' being the angle wrt normal...
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    Top 10 unis in the Uk for physics?

    Really, it depends on the type of Physics you want to do... but then I would never choose a university on prestige alone. I would pick it on 'does it feel right and would I enjoy it there' ;)
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    Electricity - i need help

    Draw the circuit and put the values in ---\/\8/\-----\/\16\/\----- | | -------\/\12/\-------- Work out the current through the 8Ω first. You are given the voltage (48V) that this uses. So your answer to I=V/R is the current through this resistor alone. Then...
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    Help with Propanal formulas

    Propanal / Propanol ? They are not the same thing, which one is it ? One is C_{3}H_{8}O propanol (has 2 forms, propan-1-ol and propan-2-ol ) The other is C_{3}H_{6}O propanal Before you even start balancing you need to know which chemical you actualy mean. From contect of...
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    Projectile Motion With Drag [Aprox's are Welcome]

    Well both should be considered independent to start with, for a projectile. Vertical distance (y) is just the effect of gravity on the object. air drag (or resistive friction is just another force. In the vertical direction it will just counter gravity and you will need to know work out if it...
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