# Search results

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...
16. ### Mains power plugs and plug packs

Yep got it! Not sure I understand. Are you following on from my oversimplification or are you talking about reality. What if the only thing I plugged in was my phone charger? I don't think you understood that last question. So you have your mains supply at 240V, then you plug in a phone...
17. ### Mains power plugs and plug packs

OK so I've always wanted to learn about how the mains power works in conjunction with things that you plug in ie. phone chargers, computer PSU's, TV's etc. Now I know here in Australia that in the home we get 240V AC at 50Hz with the standard 3-pin outlets rated at 10Amps. What do the 3 pins...
18. ### A question about the double slit experiment

I think you are missing the point completely. the observer has NO effect on the single slit experiment. The particle will act like a wave and particle in BOTH cases (Observed or not). What is stopping us figuring out its definite position in the single slit experiment? You are correct about...
19. ### A question about the double slit experiment

The layman/classical definition of a particle can not be brought into a conversation, and i think (if i read your post correct) we both agree on that. In terms of the scientific definition of a particle I would say that in what ever state, local or non-local, superposition or definite it is...
20. ### What are wave and particle nature of light theories?

Electromagnetism Photoelectric effect Quantum mechanics Special Relativity Do you need explanations?
21. ### A question about the double slit experiment

Wrong. Even when the electron is observed it will still act like a wave. The only thing that changes is the wavefunction as it collapses into a definite state. This state is still a wavefunction and still acts like a wave. Only difference is that its not a superposition of waves. I any case...
22. ### Force on a fixed object- help settle a debate please!

Yes i had the same thoughts after thinking about it some more. I was thinking about how the climber would change arms and each time he would jerk the rope. But if he was smooth in his motion his centre of mass would be moving upwards at a constant velocity. If he had at least one hand on the...
23. ### Acceleration vs accelerator

To not confuse the OP I kept it to simple straight line motion. I didn't say it but I implied that the direction of travel is positive and hence negative/decreasing change in velocity was negative acceleration. I could make the velocity negative and the acceleration positive in this example it...
24. ### What are Virtual Particles

Virtual particles are short lived particles that borrow energy from the no-so-empty vacuum of space. They adhere to the Heisenberg Uncertainty Principle \Delta t \Delta E >= \frac{\hbar}{2} . So the more massive or energetic a particle the less time it will live. I think these are known as...
25. ### Force on a fixed object- help settle a debate please!

Im just trying to imagine if the climber moved upward at a constant velocity. Just thinking about it conceptually it seems the rope would have a higher tension when moving with const velocity then if the person was stationary. But thinking about it some more it seems logical that constant...
26. ### How can bosons made of fermions occupy the same quantum state?

I would say its to do with the He-4 atoms being in a bound state. The spin of this bound state is a whole integer value (boson) and it doesn't matter about the constituent parts (fermions). If you look at low temp superconductors their electrons pair up (cooper pairs) and this pairing acts...
27. ### Acceleration vs accelerator

By definition deceleration is negative acceleration ie. the velocity is changing in the opposite direction to the motion. (velocity is decreasing)... So your statement can't be right. Or am i missing something? Did you mean to say, "The car can still be moving forward even if the car is...
28. ### Quantum amplitudes versus probability

Like mbf said we square the amplitudes and then add them as the sum of probabilities for each component of the system. Not quite sure I get what your asking?
29. ### Quantum amplitudes versus probability

The amplitudes can be negative or even complex, when you square them they become a probability out of 1 if the system is normalized.
30. ### Space as not empty, non-locality, conceptual implications?

Its true that all science fields at different times in history started finding answers to things to only find out they were left with more questions. Thats science! There may be an infinite or finite amount of these unanswered questions , either way science will keep moving forward. You seem...