Help with Quanta to Quarks! (1 Viewer)

[x.Exhaust.x]

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I:

1. How are UV rays detected through the Lyman series? Is it by charge coupled devices? How do these work? And is this even necessary for the HSC syllabus?

2. If electrons behave as classical particles, then its energy is not quantised. This is how electrons were said to behave in Rutherford's model of the atom. Explain why atoms in such a model would emit a continuous spectrum and not just certain wavelengths as we observe with the hydrogen spectrum. How is this problem overcomed in Bohr's model?

Can someone guide me through this?

3. To calculate the momentum of a photon, is it p = h / lambda?

4. a) Explain why most of the alpha particles are not deflected in the Geiger Marsden experiment experiment (the Gold foil experiment critical in Rutherford developing his model).

b) How did the Gold Foil experiment disprove the Thompson model of the atom?

5. Identify and disucss a previous EXAMPLE of the wave particle duality.

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II:

6. The Fermi neutronic reactor (CP - I) was the first example of a controlled nuclear reaction. Discuss the structure of this reactor.

7. What is the difference in the detection of alpha and beta particles by using a Wilson Cloud Chamber to detect radiation?

8. Discuss the multiple features of any nuclear reactor used for electricity generation.

9. Are there any awesome diagrams on how the de Broglie's hypothesis was proven to be correct by the Davisson - Germer experiment?

Thanks

 

[Pwnage101]

ill answer ur bolded part:

well basically, just think about it - when electrons fall from one energy level to anoyther they emit EMR - the frequency is related to the size of the energy gap. Now suppose, according to calssical physics, energy is not quantised an electrons can exist at any point around an atom, and as it falls from that point to any other energy level below it, it would emit EMR , with frequency related to the size of the gap.

If energy levels could exist at any point in space aroudn the nucleus, then, naturally, any frequency of EMR could be and would be released.

However, clearly when we observe thsi occuring, we notice line spectra - only certain frequencies of EMR are released from specific atoms, and teh reason is energyis quantised - so electrons exist only in certain, defined orbits (bohr's model proposed this). Then only certain 'falls' would be permitted, and so only certainf requencies of EMR owuld be emitted.

then just talk about bohr's atom and the other propoerties that he proposed ( if forget them)...

 

[ajay098]

if u have the jacaranda text book, it has the dotpoints at the front and tells u the page number it's under.

 

[Tully B.]

My class hasn't even started this topic. Pretty poor effort, completing just three quarters of the course...
Is it easy to understand just from reading Jacaranda?

 

[Petyo]

@Pwnage101: I'm just a little bit confused. Do you think that word "energy level" can be used when talking about classical physics? Because, as you stated, according to classical physics- energy is not quantised- So since "energy is not quantised", how come the concept of "energy levels" could possibly exists?

 

[Aerath]

My class hasn't even started this topic. Pretty poor effort, completing just three quarters of the course...
Is it easy to understand just from reading Jacaranda?

Um, I think it'd be better to get a briefer grasp of it from one of the notes on BoS resources section. Then once you get the general gist, then start referring to Jacaranda. Well, that's how I like to work - I don't wanna dive in the deep end and start garnering the 'advanced concepts' when I have no idea how the basics work.

 

[darkchild69]

1. Lyman series is not in the new syllabus, dont bother.

2. Particles orbiting a central point (i.e., nucleus) would continuously emit EMR due to change in velocity (hence acceleration) around the nucleus occuring all the time. Acceleration requires a force, a force can be equated to work done and hence energy. The energy required to make the electron accelerate would need to be applied to the electron from its internal energy and hence be "lost". This "lost" energy would be emitted in the form of EMR. As they get closer to the nucleus, this would result in greater velocity (due to conservation of angular momentum) hence greater acceleration, which coresponds to different wavelengths of EMR being emitted. Bohrs model overcame this by saying that there are certain energy levels ("stationary states") which electrons can occupy and not lose any energy.

3. Yes. lambda = h/mv (h/p)

4. Alpha particles are a Helium Nucleus (positively charged) so they will interact with other charged particles. The reason why only something like 1:8000 alpha particles deflected by any significant angle is because the positively charged nucleus is extremely small & dense and ocupies only a very small portion of the entire atom (atom is approx 10^-10m diameter, nucleus approx 10^-14). The positively charged alpha particles generally did not get close enough to the positively charged nucleus in order to experience any significant repulsion, so they were able to pass through the gold foil basically unimpeded.

b) Thomsons model (aka Plum Pudding model) was that there were mini corpuscles of negative charge inside a positive sphere. I.e., Raisins in raisin bread (raisins are the electrons and the bread is the positive charges) If this were the case and the electrons were the minority of the atom, then it would be expected that more of the positively charged alpha particles would be deflected by a significant angle, due to electrostatic interaction. The gold foil experimental results showed that this was not the case and that all of the positive charge was confined to a very small percentage of the volume of the entire atom.

5. Light - Einsteins explanation of light to explain the PE effect


Thats about all i have covered with my class and having not done this topic in 8 years, it is all i remember