Physics 2018 Senior External Examination: Assessment reportand Part B assessed Scientific processes. Part A consisted of 15 multiple choice questions and 10 short response questions

1901

24

Statistics Year Number of

candidates Level of achievement

VHA HA SA LA VLA

2018 20 4 8 4 3 1

2017 20 3 6 4 5 2

2016 17 2 4 6 5 0

2015 22 3 3 7 6 3

2014 14 0 5 4 4 1

General comments The 2018 Physics Senior External Examination was based on the Physics Senior External Syllabus 2000 (amended 2003).

Paper One Part A assessed Knowledge of subject matter and Part B assessed Scientific processes. Part A consisted of 15 multiple choice questions and 10 short response questions covering all syllabus topics. Marks allocated aligned with syllabus topic weightings. Part B contained six Scientific processes questions assessed against criteria specific to each question. Candidates were required to respond to all six questions.

Paper Two assessed Complex reasoning processes and contained six questions assessed against specific criteria. Candidates were required to respond to all six questions.

Paper One

Part A: Knowledge of subject matter Section 1 — Multiple choice questions

Question 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Correct response B C A C D C B B D B C D B D D

Physics 2018 Senior External Examination: Assessment report


Queensland Curriculum & Assessment Authority February 2019

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Question 1 Most candidates clearly understood the notion of significant figures and could apply it in the given situation. The practice of choosing the lowest number of figures in such situations seems well established.

Question 2 Candidates did not generally perform well on this question. Many candidates chose the highest point of the graph (representing velocity) as the point of highest force. Links between changes in velocity and force may need to be better made, at least in terms of visual representations of a velocity vs. time graph.

Question 3 While some candidates made basic errors in allocating signs to vectors, most candidates were able to deal with displacement vectors to calculate average velocity.

Question 4 This was a reasonably straightforward example of determining changes to one side of an equation based on changes made to the other side. This type of problem has been represented before on past papers. A number of candidates were still not able to apply their knowledge in this situation. More work on changing values in equations could be beneficial for these candidates.

Question 5 Some candidates were distracted by the information about the horizontal motion and did not correctly treat the question as a problem in one dimension. More examples of vertical motion under gravity in which information about horizontal motion can be shown to be unnecessary might be useful for these candidates.

Question 6 Most candidates were able to correctly combine the fundamental units of force and length and manipulate them algebraically, but a small number were not able to succeed at this. It may be helpful for candidates to concentrate on learning more about dimensional analysis in the future.

Question 7 Some candidates did not appear to read the answer options with sufficient care. This was an exercise in precision of terminology and, judging by their selection of option A, these candidates may not have understood the distinction between a longitudinal and transverse wave.

Question 8 Candidates were generally successful with this problem. Ohm’s law seems to have been well understood and recognised in graphical form.

Question 9 Candidates mostly did well on this question, showing that the definition of magnetic flux, which was required to complete the question, had been well learnt.



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Question 10 Candidates spread their responses over all options in this question, with only a few successful responses. This was slightly surprising since it is a straightforward application of formula and of understanding the relationship between work, energy and Ohm’s law (which was well responded to in Question 8). Exposure to more complex, though not difficult, practical problems of this sort might be beneficial to candidates.

Question 11 Candidates did well in this question, which required them to demonstrate understanding of the concept of electric fields.

Question 12 This question showed some variety in candidate responses, showing that the concept of how field lines are connected around a current carrying wire was not generally understood.

Question 13 This question also showed variety in candidate responses, indicating that some candidates either had difficulty in determining the nature of the circuit or understanding diodes or transistors in general.

Question 14 This question about atomic nomenclature was correctly answered by nearly all candidates.

Question 15 Candidates seemed to understand the concept of half-life and how to use it to calculate solutions to problems.

Section 2 — Short response questions This part of the examination required candidates to demonstrate their knowledge and ability by simple application of the syllabus topics.

Question 1 Candidates clearly understood the notion of significant figures and could apply it in the situation given. The practice of choosing the lowest number of figures in such situations seems well established.

Question 2 Candidates generally converted percentage errors into absolute errors with few problems.

Question 3 Candidates were generally successful in equating change in momentum with the product of force and time.

Question 4 This question required a reasonably straightforward application of theory and most candidates succeeded in transferring gravitational potential energy (GPE) to kinetic energy (KE) to correctly answer the question.



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Question 5 The diagram was clearly familiar to candidates, though some had difficulty expressing changes in volume with confidence and/or precision.

Question 6 As happened last year in this type of problem, most candidates were able to use the appropriate formula but some did not pay attention to the units used.

Question 7 The simple application of formula was generally done well, with the use of kilovolts (kV) in a few cases causing confusion.

Question 8 Candidates were generally successful with this problem, having no difficulty locating the relevant information. This is not surprising as it is a standard type of diagram and each year some interpretation of the diagram is required.

Question 9 Candidates generally had success in identifying and using the formula correctly.

Question 10 Candidates did well in this question, showing a good understanding of how to identify particular types of decay.

Part B: Scientific processes Question 1 This was an information-dense graphic and many candidates identified most of the necessary information to support their decisions. The question required candidates to indicate whether or not a statement was supported.

Question 2 Most candidates understood the nature of the situation and correctly responded to the question.

Question 3 As usual for this type of problem, and has been the case in previous years, the success of candidates solving it varied. It may be useful for candidates to focus on learning about key interaction points of the graph from which they could interpolate the others.

Question 4 Candidates typically plotted the points on the graph well, with a mostly sensible choice of axes. While the answer to the question of when to drink the coffee was clear from the data in the table, candidates mostly gave the correct answer, showing the data could be interpreted regardless of how it was presented.



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Question 5 Candidate use of experimental design was generally minimal, even though there were quite a few variables to be identified and controlled for in this question. Not all candidates considered working multiple trials across a range of distances and the details of measuring how wet a person could get could have been improved. Collaborative experiences in which candidates collectively brainstorm experimental designs of this type might be beneficial.

Question 6 Candidates generally seemed to have some idea of what the question was asking; however, few candidates addressed all aspects of the question. For example, the phase of the response graph might be correct but not the amplitude. Not all candidates recognised that this was a simple application of Ohm’s law.

Paper Two

Complex reasoning processes Question 1 Candidates were able to engage with the question on a variety of levels. Most could work out the values of some resistance components (simple or complex) and use these to shape their answer, even if they did not solve the final answer.

Question 2 Candidates generally understood the nature of the problem and could work meaningfully towards a solution. Some candidates did not synthesise all the available information or formulae.

Question 3 Candidates who recognised the question as one of determining a spring constant were generally successful in this question. Candidates might have found examples from previous years helpful in identifying the type of question and a useful approach.

Question 4 Candidates generally recognised this question as one involving the relationships between power, work, force and time and that a trigonometry component in the solution was necessary. The extent to which they worked through this successfully varied but many did well.

Question 5 This question was commonly approached as a simple conservation of momentum problem but sometimes candidates did not consider that the acceleration of the rocket was increasing linearly. This insight, from an application of Newton’s second law of thermodynamics, was a necessary condition to successfully solve the problem.

Question 6 This was a complex question but candidates who worked through the trigonometry and Snell’s law equations achieved a measure of success even if they did not succeed through to the



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final answer. Candidates generally had the technical knowledge to complete the question but some did not appropriately negotiate the complexities.

Marker responses The sample solutions on the following pages show possible ways of successfully responding to the questions. Other approaches and problem-solving strategies may be equally valid.



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Paper One



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Paper 2 Question 1



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Question 2



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Question 3



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Question 4



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Question 5



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Question 6



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Documents

Physics 2018 Senior External Examination: Assessment reportand Part B assessed Scientific processes. Part A consisted of 15 multiple choice questions and 10 short response questions