2020 HSC Physics Exam Review

by James Leatherbarrow, publised 28 November 2020

This year’s HSC Physics examination was the second iteration of the new syllabus, and it already appears that NESA seem to be following a trend regarding the style of their examinations for Physics. Note that this idea of a “trend” should be taken with a grain of salt, as the HSC is defined by its uncertainty. The main purpose of this article is to highlight key aspects of the examination for this year that were surprising, as well as comparing this to the 2019 examination.

This was quite a challenging paper overall, and students that better understood the meaning behind the physics and how the syllabus interrelates between modules would have seen more success.

Mark Allocation:

The approximate mark distribution of the Physics paper split into the 4 modules of the syllabus are as follows: (Totalling 100):

            Module 5 (Advanced Mechanics): 29.5 (Multiple Choice - 5.5)

            Module 6 (Electromagnetism): 22.5 (M.C. - 4.5)

            Module 7 (The Nature of Light): 23 (M.C. - 4)

            Module 8 (From the Universe to the Atom): 25 (M.C. - 6)

Something that is very notable in this paper is the focus on questions which test understanding of multiple modules simultaneously, which was not present as often in the 2019 exam. From the mark allocation, Advanced Mechanics was tested the most, and it was often asked in tandem with Module 6 concepts. This is mainly seen in the last three questions of the paper as well as one of the multiple choice questions. There was also one question containing both Module 7 and Module 8 topics.

Section I (Multiple Choice):

Regarding the 20 multiple choice questions, as always with Physics these are quite conceptual and often very difficult for the average student, and consequently can chew up a lot of time. The first 11 are relatively straightforward, mainly testing basic ideas. Questions 12-17 are more difficult and require a stronger understanding of how the physics actually works in the situations of each question. As with most HSC papers, the last 3 questions separate the cohort and often take the most time to really grasp how they work. These questions are typically accompanied by a large diagram and have lots of things going on at once and/or are quite conceptual. Tips as to how to best approach these questions include taking time to break it down and identify key ideas that will have to be applied, before looking at the different answers and considering which one will be the most viable. Something to understand is that it is not worth wasting excess time on these questions when there are 80 other marks in the paper to come. Another thing that was surprising in this section was that there was only really one mark allocated to a pure calculation, and even this was based off a graph. Other quantitative questions did not want a numerical answer, but rather asked students to compare different situations or choose the most appropriate representation of the scenario.

Section II (Longer Response):

Let’s now move on to section 2 of the paper and talk about the longer responses. There were 26 marks allocated for calculations and deriving expressions and 38 marks allocated for explanations and diagrams, with the remaining 16 marks present in questions which asked for both. The ideas behind these questions would have been easy to identify by students, however subtle changes to the wording made the questions slightly more specific and more application was required. Something to notice is that many questions that had several components to them had a mixture of calculation and theoretical questions. This is crucial as it tests a student’s understanding of why a calculation works. This becomes even more apparent in the 7 and 9 mark questions as students are asked to present both qualitative and quantitative information to support their answer. Such an idea was also present in the 2019 examination, and it is very likely that such questions will continue to appear in the future. To summarise this idea, students should ensure that they understand WHY calculations (as well as theory) work, and practice using mathematical models to support written responses in order to maximise marks gained from these larger questions as this is where the majority of the cohort will be separated. This is especially important for Module 5 as it is important to understand that this module is not just purely calculations, and that really difficult hybrid qualitative/quantitative questions can be made from this module, as seen from this paper.

Key Ideas/Final Points:

• Being able to relate every concept in Physics to the Law of Conservation of Energy.
• Being able to interpret information from diagrams and know what to do with it.
• Knowing what equations to use and what units each value has (you will lose a whole mark if your answer does not have the appropriate units (this includes direction if you are asked to provide a vector quantity)).
• Read the question: understand what the question is actually asking before diving into it. Break it apart and plan out what you will talk about, especially for longer responses.
• Know how to derive expressions/formulae.
• Know your experiments and their limitations.          
• Don’t freak out when you see a complex diagram or something that you think you cannot do- as with every other question just take time to break it down and really think it through.
• Know how all the modules can interconnect and practice questions where they do.
• Be able to write coherently and concisely and don’t provide meaningless/irrelevant information.
• Understand WHY things work- it appears that NESA is shifting away from asking questions where rote-learning is efficient and asking more questions that need you to apply your knowledge and understanding in strange situations.