# Recent content by crissyb1988

1. ### Help understanding Acceleration

Acceleration (m/s/s OR m/s^2) describes changes in velocity m/s. If acceleration is constant in this scenario then velocity will be CHANGING at a constant rate. So at 1 second the velocity will be 2 m/s NOT 2 m/s^2 (this would be acceleration) and at 2 seconds the velocity will be 4 m/s NOT 4...
2. ### Collapse of Wavefunction, Double-Slit Experiment

Now I'm trying to imagine the wavefuction before and after collapse when measured at either slit. Before the particle enters the slits I imagine the wavefunction more as a planar wave with no definite position (single wavenumber and a superposition of positions). If no measurement is made then...
3. ### Superconductors and the Meissner Effect

If the external magnetic field is not changing over time then the electrons won't react to it. Am I wrong to apply it here? \nabla\times E=\frac{-\partial B}{\partial t} I will look into this
4. ### Superconductors and the Meissner Effect

Yep that makes sense. My point is that the EXTERNAL magnetic field DOESN'T vary with time. If the external field isn't changing then how are currents being produced in the superconductor? These currents are responsible for expelling the external field, which hasn't changed. Look at...
5. ### Superconductors and the Meissner Effect

The Meissner effect is the main difference. Because according to Maxwell's equations a static field doesn't create a current and therefore no mag field is expelled from the bulk of the material. I wasn't sure about apparent breaking of energy conservation laws, and of course we don;t have a...
6. ### Superconductors and the Meissner Effect

So I'm a little confused about the Meissner Effect. If we have both a perfect conductor and a superconductor (both above Tc) and place them in a magnetic field and lower their temperatures so they exhibit their respective properties, the magnetic field inside the perfect conductor persists...
7. ### Why is a current induced in a conductor placed in a changing m.field ?

The induced current creates an opposing magnetic field in a conducting loop. Like I said in my first post there are some subtle consequences of all this that will only be appreciated through further study of maxwell's equations, namely invariance, conservation of energy etc. QFT would be the...
8. ### Why is a current induced in a conductor placed in a changing m.field ?

Yes the magnetic field interacts with electrons. Any charged (positive or negative) particle interacts with magnetic fields. If we look at this from a QFT perspective the magnetic field is made up of (not sure the correct wording here) virtual photons that mediate electromagnetic force...
9. ### Why is a current induced in a conductor placed in a changing m.field ?

I think the OP KNOWS what happens when you put a wire in a mag field, he/ she just wants a deeper descripton of what's happening on a smaller scale
10. ### Why is a current induced in a conductor placed in a changing m.field ?

In simple terms, the Lorentz force. Just like a free moving electron in a magnetic field feels a force, so does a conducting wire (made up of many electrons). Leading on from the Lorentz force, special relativity demands that electricity and magnetism are one in the same, just different...
11. ### Mains power plugs and plug packs

yea fair point. thanks anyway!
12. ### Mains power plugs and plug packs

Can anyone point me in the direction of a circuit diagram that shows mains power to breaker to house to appliances. I kinda get whats going on but I understand things better with a visual representation. BTW thanks for the input guys
13. ### Mains power plugs and plug packs

OK so impedance is more like the "resistance" the transformer imparts on its self due to the oscillations of currents and it has to fight against its own change. So the mains power "sees" the charger with a certain impedance and allows the appropriate current flow. Can the impedance of the...
14. ### Mains power plugs and plug packs

I get you now. So there is physically a limit to how many appliances you can have plugged into all your outlets depending on the current the impedance allows them to draw. 1/Rtotal = 1/R1 + 1/R2 and Itotal = I1 +I2. So current total must be less than 10 amps for the whole household?
15. ### Mains power plugs and plug packs

Im still not sure what your trying to say. When you say plug in a hundred phone chargers... do you mean to the same outlet (in series or para?) or the whole house (ie. plugged into many outlets around the house)? Also wouldn't more chargers mean a higher resistance and therefore lower the...