Oxbridge Physics Mock Interview at Latymer

The idea of the mock interview is for us to have an Oxbridge-style interview with someone we’ve never met before. These took place at Latymer Upper School (on King’s Street), and my interviewer was from St Paul’s Girls’ School.

I went into the interview room and the first thing I was asked was why I wanted to apply to Oxford for Physics, at which point I explained that actually I was applying to Cambridge for Phys Nat Sci but due to an error I was down for Physics at Oxford. He said it was fine and didn’t actually let me explain why I wanted to apply for my course, and straight away asked me to differentiate a pretty standard quadratic. I did it and predicted the next question would be to do it from first principles (which it was). I got as far as the second line (writing Lim(Dx→0){the entire mess before it simplifies}) before he cut me off and asked me whether I knew about radioactive decay. I cautiously said yes, at which point he asked me to write down the equation, then derive it from first principles. I wrote down the ODE, separated variables and proved the formula. He then asked me what I knew about how calculus was conceived. I hadn’t gone to the Newton/Leibnitz Maths Soc lecture but I knew enough about the history (thank you Simon Singh!) to say that they had independently invented calculus at the same time. He asked me what Newton was researching at the time and I said gravity, and was about to go into detail at which point he asked me what I knew about Leibnitz. I confessed that I didn’t know much about him, and he said it’s fine – ‘he’s a mathematician – nobody really cares what they were researching’ (in case readers haven’t already worked it out, he was playing bad cop). He asked me why it’s impossible to say who was the first to invent calculus (which I at first misinterpreted and talked about the different notation which I was going to relate back to something but I now forget) to which I talked about research taking time and that they probably each took lots of time to formulate calculus, and it can’t just be proven who was first by who was the first to submit the paper. He implied it was really about fast communication and he asked whether I knew how research is now distributed. I talked about papers being published online (the arXiv logo jumped to mind though I didn’t mention it) at which point he asked me what scientific papers / magazines I read. I said New Scientist and Scientific American (I could have mentioned Physics/Chemistry Review etc. but I didn’t for some reason), and he asked me to talk about an interesting article I read recently. I started enthusing about this awesome article I’d read in Sci Am about semiclassical gravity – formulating QFT on the hyperbolic geometry of general relativity and possibly proving singularities cannot be formed. Before I could get to the crux of the issue (black stars, repulsive forces etc.) he asked me what I knew about black holes. I started talking about singularities and he asked what terminology I know concerning black holes. I said a list including accretion disks, Hawking radiation, event horizons. He asked me to define all of those. I defined the event horizon, then started talking about an effect which had nothing to do with Hawking radiation (axial plumes coming from the black hole, with an accompanying utterance about conservation of angular momentum and fast spinning) but saved myself just in time and said something about virtual particles being created and destroyed. I mentioned proving virtual particles with the Casimir Effect just before I got to the crux of Hawking Radiation, at which point he interrupted me again to explain the Casimir Effect. I said what I knew – something to do with an attraction between two metal sheets.

At approximately that point he said ‘that’s it’ and that I did fine. He explained he’d been playing [not his words] ‘bad cop’ (by then I’d worked out that either that was the case or he was just in a really bad mood because everything was behind schedule (!)) and that I reacted well under that. There’s a reason I’ve written all that in one paragraph – the interview felt exactly like one continuous rush of me going through almost every bit of classical (and some non-classical) physics I’ve ever come across in half an hour (it felt a lot shorter than that)! It felt a bit like some of the ‘Achilles and Tortoise’ recursion stories out of GEB by Hofstadter in that he kept cutting me off before I could finish one thing, but as it turned out that was the whole point.

At some point he also asked me about the difference between resistance and resistivity (object vs intrinsic material property) and I asked whether I should write the equation connecting them at which point he said ‘yes that might be nice’. He must really get a kick out of playing bad cop! He then asked what causes resistance and what happens to resistivity when you heat something – I drew the approximate structure of a metal and talked about electrons hitting metal cations, and that when temperature rises the cations vibrate more. He asked me to be clearer about ‘more’ – I said greater amplitude and hesitated on saying greater frequency trying to remember the SHM equation for energy (I thought I might have been being ‘browbeaten’ into assuming frequency would increase and in my panicked state I couldn’t remember properly!). I must have said something about SHM and he asked me what that was – I wrote the ODE and said what it meant in words (forgot to write it in x=(x0)sin(wt+phi) form), to which he said nothing and moved on. I can’t remember how that episode fitted in, so I left it out of the mega-paragraph.

Anyways overall, I almost hope my Cambridge interview ends up going like that. I feel I’m now more resistant to intimidating interviewers and have read relatively widely so an interview basically inviting me to talk about what I know about physics until I run out of breath and pass out on the floor (Calvin & Hobbes reference) would be pretty much perfect. He didn’t actually ask me to solve any physics problems, which was not what I was expecting, but hey.


3 Responses to Oxbridge Physics Mock Interview at Latymer

  1. Tom T says:

    TBH it sounds as though he was a bit intimidated by the fact you were cleverer than him. It seems a bit weird that he’d keep moving from topic to topic. (quite hypnotic)

  2. Meh.. says:

    He was evidently searching for something you couldn’t cover properly. Had he found it, he would have kept pushing with that topic. I guess that’s what interviewers try and do – find something you know little about and then try and make you work it out. (Un?)fortunately for you – his attempts were akin to firing a laser to a perpendicularly positioned mirror. :(

  3. Meh.. says:

    “at a perpendicularly..”… damn.

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