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I want to score high on my physics final, but how?

  1. Nov 18, 2008 #1
    Perhaps I am not reading the chapters enough, but this is just intro to physics where there aren't even any math equations to compute. It is simply the concepts and nature of things like light, heat, phase change, etc.

    The final exam which is in a few weeks covers everything from day 1, it's cumulative. I've been reading the chapters again however it is a thick book. I have been reading thoroughly so should I Just keep reading or am I just too slow to understand physics? I have a keen interest in it and want to understand

    For example, I attended the lecture on magnetism and electromagnetic induction, and to sum it up I could say that magnetism is emitted by charges in motion, which is electrical current. When there is a change in the magnetic field, electromagnetic induction occurs, and an electrical current is produced. The two are bound together.

    Right now I am reading about light, and I can say that the reason why light travels at the speed it does is because of the conservation of energy. If it traveled any slower the wave would die out.
  2. jcsd
  3. Nov 19, 2008 #2
    Magnetism is more of a property. A magnetic field is what's produced by electric current.

    The equation (Maxwell-Faraday equation) is formulated in terms of an electric potential resulting from a change in magnetic field that passes through a closed loop. It can be interpreted as the current flows in such a way as to try to re-establish the magnetic field of previous instances in time. If an external magnetic field increases with time through a loop, current will try to flow so that the magnetic field that results from the current summed with this external field comes close to what the external field was before.

    I don't know if this information helps, but with an intro class like you describe it must be really hard to really understand physics.

    I'm not sure I agree with your assessment. It is theoretically possible to slow down the speed of light but keep the transmission of the light lossless. Why light travels at the speed of light is a trickier question though, but I don't think why the speed of light must be the speed of light was really understood until Einstein. The core of the problem is, depending on your frame of reference, a moving charge will appear to produce different electric/magnetic fields. However, the energy of these fields must be constant in all frames of reference.
    Last edited: Nov 19, 2008
  4. Nov 19, 2008 #3
    Well, you could also note that both fields are the same and only appear different because of different reference frames. So the electric field and the magnetic field are the same.
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