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Pretty sure it's B...

Thanks dude, your explanation was really helpful. But with the bit I bolded, wouldn't it be more correct to say that holes move in the opposite direction to electrons in the valence band, given that most electrons which are moving are not located in the conduction band, but are moving within the...

re: HSC Physics Marathon Archive I talked about this in an exam once for Physics and my teacher said that it was mainly unnecessary, especially when the question is only worth 3 marks. However, you do raise a good point, and personally I reckon it'd be useful to mention the 2dsintheta stuff...

Yeah ok. Holes is what I would have talked about anyway, given that I wasn't even familiar with the term 'acceptor level' until today. But was my explanation correct?

Thanks guys. Just clarifying: the 'acceptor level' is the amount of energy needed for an electron in silicon (or germanium) to be 'accepted' by the group III element e.g. boron. This amount of energy is much less energy than is required for the same electron to enter the conduction band of...

re: HSC Physics Marathon Archive The Braggs shone a beam of X-rays at a crystal surface, which produced a diffraction pattern on a detector. When the angle of incidence was altered, the changes in the diffraction pattern allowed the Braggs to mathematically determine the spacing between...

Found this in 2009 HSC. Can someone please explain to me what the terms 'donor level' and 'acceptor level' refer to? I've never heard them before. Thanks

+1 It's helpful to say n1 = kn2 where k is the ratio of moles of reactants

re: HSC Chemistry Marathon Archive 1. Polyvinyl chloride and polystyrene are both addition polymers formed from the polymerisation of vinyl chloride (chloroethene) and styrene (ethenylbenzene) respectively. Both processes involve using an organic peroxide radical to initiate the process of...

Yes you're right. There are actually 2 dot points involved here, one concerns a physical MODEL of equilibrium, while the other one concerns an investigation to qualitatively analyse an equilibrium reaction. sy37 seems to have mixed them up :) A good model to use is 2 buckets of water with water...

Tbh I'm hoping for a typical harder 3 unit algebra style question for q16, like last year's 16b or something like that. I doubt there'll be a super hard circle geom qn seeing as they did that in 16a last year. I wouldn't be surprised if they did a super hard combinatorics question

re: HSC Chemistry Marathon Archive I need some help with this question y'all. The marking guidelines state that we should list several problems with current use of petrochemicals, and several environmental effects. For the former, I thought of: 1. Petroleum is a non-renewable source: our...

Re: HSC 2015 4U Marathon

Re: HSC 2015 4U Marathon Ah yes I see it now. Both methods are quite efficient, in my opinion

Re: HSC 2015 4U Marathon Finally a question from Paradoxica which I could actually do :p

Re: HSC 2015 4U Marathon Ah I think I have the answer, let me write up a solution

Re: HSC 2015 4U Marathon Here's a classic mechanics question: \textup{A car travelling at speed v metres per second along a banked} \textup{curve of radius r metres experiences no lateral frictional force.} \textup{Another car of mass m travels along the same curve at speed V}...

Also, I think the whole idea of finding an 'equation' for I (where I is the integral) is a mainly 4U concept

Thank goodness

inb4 69%