Physics Predictions/Thoughts (3 Viewers)

[Arrowshaft]

That question in the CSSA was pretty bad as well, I mentioned it had something to do with neutrinos when I was answering it, but had never heard of Pauli in my life lol. It had a similar really stupid question that was a 5 marker where you literally just had to mention Einstein's postulate about the speed od light being constant, and then the wntire sample answer was waffle about "Galilean Relativity". The catholic papers are really terrible.

DID YOU SEE THE CENTRIPETAL FORCE QUESTION THOUGH? How stupid was that?!! And of their projectile motion question was so wack and they provided the wrong answer, smh.

 

[Drdusk]

Furthermore, weirdly, the sample answers said that special relativity's consequences did not need physical experimental validation. Instead Einstein's thought experiments were enough. However, I thought that Einstein's thought experiments have no inherent basis in reality, and were simply used to develop the predictions and consequences of special relativity.

I can confirm this is a complete bullshit of an answer. Don't write this in your Hsc lads. The reason Einstein didn't get a Nobel prize for it aside from the fact that the people on the council hated him was because they didn't have a way to physically verify it.

 

[Arrowshaft]

I can confirm this is a complete bullshit of an answer. Don't write this in your Hsc lads. The reason Einstein didn't get a Nobel prize for it aside from the fact that the people on the council hated him was because they didn't have a way to physically verify it.

Exactly! Independent markers must’ve been high

 

[TheOnePheeph]

DID YOU SEE THE CENTRIPETAL FORCE QUESTION THOUGH? How stupid was that?!! And of their projectile motion question was so wack and they provided the wrong answer, smh.

Yes, the projectile answer was stupid, iirc they got their answer by using the initial velocity in a which was completely different lol. The explanation in the centripetal force one was also plain wrong and had no understanding of balancing forces.

 

[Arrowshaft]

Yes, the projectile answer was stupid, iirc they got their answer by using the initial velocity in a which was completely different lol. The explanation in the centripetal force one was also plain wrong and had no understanding of balancing forces.

Hahaah i legit lol’d when I see them using pythagoras hahaha

 

[Hscbuzman]

Who here reckons this answer (The first question) scroll down to the third page to see it all was marked poorly. 9/9 for sure.

 

[Arrowshaft]

Who here reckons this answer (The first question) scroll down to the third page to see it all was marked poorly. 9/9 for sure.

Nice response however, seeing it is a nine marker i also wouldve mentioned the magnetisation of the iron core due to the rapid change in magnetic flux causing energy to be lost - prevention: use new materials which are resistive to the de- and re-magnetisation of the core. Also, I noticed you did not EXPLAIN the effect of a soft iron core. I would have mentioned the use of ferrites which are good transmitters of magnetic flux and poor conductors of electricity (unless I missed something). i also agree that you should’ve tied in the law of conservation of energy, as you have to mention the production of heat is really a TRANSFORMATION of electrical energy into thermal energy through ohmic heating. Although, you may have been slightly less detailed in that sense, I still would have awarded 9 marks for that response, I’d say the use of conservation of energy is more of an added bonus.

 

[lplsz2000]

Nice response however, seeing it is a nine marker i also wouldve mentioned the magnetisation of the iron core due to the rapid change in magnetic flux causing energy to be lost - prevention: use new materials which are resistive to the de- and re-magnetisation of the core. Also, I noticed you did not EXPLAIN the effect of a soft iron core. I would have mentioned the use of ferrites which are good transmitters of magnetic flux and poor conductors of electricity (unless I missed something). i also agree that you should’ve tied in the law of conservation of energy, as you have to mention the production of heat is really a TRANSFORMATION of electrical energy into thermal energy through ohmic heating. Although, you may have been slightly less detailed in that sense, I still would have awarded 9 marks for that response, I’d say the use of conservation of energy is more of an added bonus.

Hi, thought you are really good at physics, do you reckon there's the need to understand Hertz's experiment? To what degree? Cause both the PEM paper and matrix education mentioned about it. But I couldn't find in on the syllabus. What's your thought? Thanks a lot. Also what are the other grey areas that you would suggest me to look at, e.g. Hubble's law?

 

[TheOnePheeph]

Hi, thought you are really good at physics, do you reckon there's the need to understand Hertz's experiment? To what degree? Cause both the PEM paper and matrix education mentioned about it. But I couldn't find in on the syllabus. What's your thought? Thanks a lot. Also what are the other grey areas that you would suggest me to look at, e.g. Hubble's law?

Not arrowshaft but for Hertz' experiment I never remember it being in the syllabus, unless I missed the lesson for our class covering it for some reason. I would still mention the fact that he did it as it supplies evidence for Maxwell's predictions of EM waves besides light, as well as oscillating charges causing E.M radiation. I don't think you need to know the experimental design, but someone please correct me if I'm wrong about this.

As for Hubble I would mention everything about how Cepheid Variables, which had period proportional to luminosity, were used with their apparent brightness and the Stefan Boltzmann law (The equation for this is not required)to measure distance, then say that spectral lines of stars were redshifted, due to the doppler effect, meaning stara were receding, and this redshift was measured to determine recession velocity. Then just describe his relationship i.e distance from earth is proportional to recession velocity which showed the expansion of the universe.

 

[akkjen]

Not arrowshaft but for Hertz' experiment I never remember it being in the syllabus, unless I missed the lesson for our class covering it for some reason. I would still mention the fact that he did it as it supplies evidence for Maxwell's predictions of EM waves besides light, as well as oscillating charges causing E.M radiation. I don't think you need to know the experimental design, but someone please correct me if I'm wrong about this.

As for Hubble I would mention everything about how Cepheid Variables, which had period proportional to luminosity, were used with their apparent brightness and the Stefan Boltzmann law (The equation for this is not required)to measure distance, then say that spectral lines of stars were redshifted, due to the doppler effect, meaning stara were receding, and this redshift was measured to determine recession velocity. Then just describe his relationship i.e distance from earth is proportional to recession velocity which showed the expansion of the universe.

Are Cepheid Variables and Stefan Boltzmann law something you learnt in class? Never heard of them, guess I need to learn them if its apart of the syllabus

 

[Arrowshaft]

Yep pretty much what TheOnePheeph said. Don’t worry too much about the experimental design but explain how he validated Maxwell’s Theory. Also, for Hubble’s Law I wouldn’t worry too much about the Cepheid Variable. Basically, what that means if you didn’t know is that this female scientist Henrietta Leavitt measured the luminosity of similar distance stars from the large and small megallanic cloud and found a relationship between luminosity and period. Usong this, Hubble was able to identify Cepheid Variables to determine positions of the clusters and stars. However, I do think it is a bit extra (unless you get like a 6+ marker on it which I highly doubt). I think it would suffice to just mention red shifting and the trend he noticed how the further a cluster was, the faster it moved (greater red shifting).

 

[Arrowshaft]

Are Cepheid Variables and Stefan Boltzmann law something you learnt in class? Never heard of them, guess I need to learn them if its apart of the syllabus

Stefan Boltzmann law is pretty much a mathematical description of how luminosity, surface area and temperature are related, so no, you do not need to know it at all - however, if you want to impress the markers then go for it, its also a nice way to tie all the relationships together

 

[TheOnePheeph]

Are Cepheid Variables and Stefan Boltzmann law something you learnt in class? Never heard of them, guess I need to learn them if its apart of the syllabus

I don't even know if they are actually part of the syllabus, but yeah we went over them in class, and they are mentioned in excel's sample answers for stuff relating to Hubble's law. So silly how much there is that we don't know if they could assess or not.

 

[ABBAS38]

Yep pretty much what TheOnePheeph said. Don’t worry too much about the experimental design but explain how he validated Maxwell’s Theory. Also, for Hubble’s Law I wouldn’t worry too much about the Cepheid Variable. Basically, what that means if you didn’t know is that this female scientist Henrietta Leavitt measured the luminosity of similar distance stars from the large and small megallanic cloud and found a relationship between luminosity and period. Usong this, Hubble was able to identify Cepheid Variables to determine positions of the clusters and stars. However, I do think it is a bit extra (unless you get like a 6+ marker on it which I highly doubt). I think it would suffice to just mention red shifting and the trend he noticed how the further a cluster was, the faster it moved (greater red shifting).

Question. If it asked to outline a method to measure the speed of light, besides astronomical and time of flight methods like the cogwheel could we go with resonance and interferometry methods and basically explain Hertz experiment in evaluating the value of the speed of light? Thanks in advance.

 

[Arrowshaft]

Question. If it asked to outline a method to measure the speed of light, besides astronomical and time of flight methods like the cogwheel could we go with resonance and interferometry methods and basically explain Hertz experiment in evaluating the value of the speed of light? Thanks in advance.

I’d say that is reasonable as a modern measurement, in fact I was also thinking of using interferometry as a modern technique

 

[TeheeCat]

Good luck on the exam tomorrow, everyone! Remember we will be free after this.

A question: What exactly are we supposed to know for Schrodinger's contribution? All I know is his equation but nothing else...

 

[akkjen]

Good luck on the exam tomorrow, everyone! Remember we will be free after this.

A question: What exactly are we supposed to know for Schrodinger's contribution? All I know is his equation but nothing else...

isnt his equation complex as maths that most of us cant understand yet lol,
id thought u just need to know that it is probablility of electrons being somewhere

 

[TeheeCat]

isnt his equation complex as maths that most of us cant understand yet lol,
id thought u just need to know that it is probablility of electrons being somewhere

It is, though I don't think they will expect us to derive his equation. I can't even find a textbook that goes into depth of this. And yeah, that's all I know too but I'm just wondering if there's something else I missed

 

[Arrowshaft]

Good luck on the exam tomorrow, everyone! Remember we will be free after this.

A question: What exactly are we supposed to know for Schrodinger's contribution? All I know is his equation but nothing else...

Woah, you memorised his equation?? for schrodinger just know how he introduced quantum ideas and the shift from a deterministic view on subatomic interactions to a probabilistic view, it uncovered the probabilistic nature of quantum particles. Also, explain how his model was also an improvement of de Broglie’s, where he defined the electron waves as a probability density of finding a particular electron within a specific orbitals. I’d also mention the different s p d f orbitals if you do chemistry and explain their shapes. Also talk about his wavefunction and the significance of the collapse of a wavefunction in the probability of finding an electron within an orbital. If you can, also mention the work of Dirac in using Schrodinger‘s ideas coupled with special relativity to discover the existence of anti-particles, and the work of Heissenberg and his uncertainty principle, and how it further supported the probabilistic nature of quantum physics

 

[Arrowshaft]

It is, though I don't think they will expect us to derive his equation. I can't even find a textbook that goes into depth of this. And yeah, that's all I know too but I'm just wondering if there's something else I missed

If you find a textbook that can describe his equations, that’d be a quantum electrodynamics textbook at uni haha