AQA AS Physics Paper 1 January 2018 Markscheme Analysis | AQA AS 物理试卷1 2018年1月评分标准分析

📚 AQA AS Physics Paper 1 January 2018 Markscheme Analysis | AQA AS 物理试卷1 2018年1月评分标准分析

This article provides a topic-by-topic breakdown of the AQA AS Physics Paper 1 (7407/1) from the January 2018 series. Rather than simply reproducing mark-scheme lines, we analyse the reasoning behind each marking point, the command words used, and the most common student errors reported by AQA examiners. Use this guide to understand how marks are awarded and how to secure them in your own exam.

本文对 AQA AS 物理试卷1（7407/1）2018年1月考卷进行逐专题解析。我们不满足于照搬评分方案，而是深入分析每个得分点背后的逻辑、题目中的指令词以及考官报告中反复出现的学生典型错误。通过本文，你将理解分数是如何授予的，以及如何在考试中稳稳拿下这些分数。

1. Paper Structure and Key Data | 试卷结构与关键数据

AS Physics Paper 1 is a 1 hour 30 minutes written exam worth 70 marks, contributing 50% of the AS qualification. The paper covers five core topic areas: measurements and errors, particles and radiation, waves, mechanics and materials, and electricity. Approximately 15 marks are allocated to Section A (multiple choice) and 55 marks to Section B (structured and extended response questions).

AS 物理试卷1 为 1 小时 30 分钟的笔试，满分 70 分，占 AS 总成绩的 50%。试卷覆盖五大核心专题：测量与误差、粒子与辐射、波动、力学与材料、电学。其中 A 部分（选择题）约 15 分，B 部分（结构化与拓展作答）约 55 分。

Paper code: 7407/1 — this is closed-book, no equation sheet provided (data sheet given).
试卷代码：7407/1 —— 闭卷考试，不提供公式表（但提供常数与数据表）。
Calculator permitted; all answers must show full working for calculation marks.
允许使用计算器；所有计算题必须展示完整过程才能获得过程分。

Question order in the 2018 paper followed the specification sequence: particles first, then waves, mechanics, materials, and electricity. Each section is clearly labelled in the question booklet, so you should allocate time proportionally: roughly 1 minute per mark, leaving 10 minutes at the end for checking.

2018年试卷的题目顺序严格依照考纲序列：先粒子，后波动、力学、材料、电学。答题册中每部分都有明确标注，因此你应合理分配时间：大约每分钟做 1 分的题，最后留 10 分钟检查。

2. Assessment Objectives and Command Words | 评估目标与指令词

The mark scheme classifies every mark under an Assessment Objective (AO). AO1 tests knowledge and recall (approximately 25% of marks), AO2 tests application and analysis (approximately 45%), and AO3 tests experimental skills and evaluation (approximately 30%). Recognising the AO type helps you decide how much detail is required.

评分方案将每一个分数归属到特定评估目标（AO）之下。AO1 考查知识记忆与复述（约占 25%），AO2 考查应用与分析（约占 45%），AO3 考查实验技能与评价（约占 30%）。识别题目所属的 AO 类型，有助于你判断需要写到多详细。

The table below summarises the command words that appeared most frequently in the January 2018 mark scheme and how examiners expected students to respond.

下表总结了 2018 年1月评分方案中出现频率最高的指令词，以及考官期待学生如何作答。

Command Word 指令词	Required Response 要求
State / Give 陈述/给出	Single word, phrase, or value. No justification needed. 一个词、短语或数值，无需解释。
Show that 证明	Demonstrate a given result using a calculation; do not just write the result. 通过计算演示给定结论，不能直接写出结果。
Calculate 计算	Full working plus correct answer with units. 完整步骤、正确答案及单位。
Explain 解释	A prose answer linking cause and effect, using physics principles. 用物理原理将因果关系表述清楚。
Determine 确定	A value may be read from a graph or may require calculation. 数值可从图中读取，也可能需要计算。

3. Section A – Multiple Choice Strategies | 选择题策略

The 15 multiple-choice questions in Section A each carry one mark. The mark scheme confirms that wrong distractors are chosen by students who make one specific error: reading the graph scale incorrectly, mixing up SI prefixes, or using the wrong equation. In particular, prefix conversions (milli, micro, nano) and unit conversions (cm to m) appeared as the leading cause of incorrect answers.

A 部分的 15 道选择题每题 1 分。评分方案显示，选错干扰项的学生通常犯了某一类特定错误：读图时看错刻度、混淆 SI 词头、或用错公式。尤其值得注意，词头换算（毫、微、纳）和单位转换（厘米到米）是选错答案的首要原因。

Always write down the relevant equation before looking at the options. 先写下相关公式，再查看选项。
For calculation-based MCQs, work out the answer to 2 significant figures first and then match; do not estimate in your head. 对基于计算的单选题，先算到两位有效数字再匹配选项，不要心算估算。
If an option is a negative value for a quantity that cannot be negative (e.g. kinetic energy), eliminate it immediately. 若某选项为负值，而该物理量不可能为负（如动能），立即排除。

In the January 2018 paper, the multiple-choice section ended with a question on the direction of the resultant force on a mass moving in a vertical circle. The mark scheme notes that more than 60% of candidates successfully identified that the resultant force is not directed towards the centre at all points because the speed is changing. This is a recurring conceptual trap: circular motion only has constant speed when the resultant force is purely centripetal.

2018年1月试卷的单选题部分以一道“竖直圆周运动物体所受合力方向”的题目收尾。评分方案指出，超过 60% 的考生能够正确判断：由于速度大小在变化，合力并非在所有位置都指向圆心。这是一个反复出现的概念陷阱：只有当速率恒定时，合力才纯粹提供向心力。

4. Particles and Radiation – Marking Points | 粒子与辐射——评分点

The first structured question in the January 2018 paper asked candidates to state the quark composition of a proton and a neutron, then to write the equation for beta-minus decay. The mark scheme required exact quark notation: a proton is uud, a neutron is udd. For the β⁻ decay, the equation must show a neutron changing into a proton plus an electron and an antineutrino:

2018年1月试卷的第一道结构化问题要求考生写出质子与中子的夸克组成，然后写出 β⁻ 衰变方程。评分方案要求精确的夸克记号：质子为 uud，中子为 udd。对于 β⁻ 衰变，方程必须显示一个中子转变为一个质子加一个电子和一个反中微子：

n → p + e⁻ + ν̄ₑ

Three marking points were available: correct quark change (uud from udd), correct lepton number conservation, and correct symbols. A common error reported in the examiner’s comments was writing the antineutrino as ν rather than ν̄, which loses the lepton-number mark because the bar symbol is what distinguishes a particle from its antiparticle.

该题共有 3 个得分点：夸克变化正确（从 udd 变为 uud）、轻子数守恒正确、符号书写正确。考官报告中提到的一个常见错误是将反中微子写成 ν 而不是 ν̄——横杠符号是区分粒子与反粒子的关键，漏写横杠会失去轻子数守恒的分数。

A follow-up part required calculation of the maximum kinetic energy of the emitted electron. The mark scheme accepted:

后续一问要求计算发射出电子的最大动能。评分方案接受以下做法：

KE_max = Δmc² = (m_n − m_p − m_e)c²

Note that AQA’s mark scheme allows candidates to work entirely in mass units and convert to energy using E = mc², or to use the Q-value approach. The significant-figure mark (to at least 2 s.f.) was essential: answers such as 0.71 MeV or 0.710 MeV were accepted only if the unit was stated.

请注意，AQA 评分方案允许考生直接使用质量差，通过 E = mc² 换算能量，也允许使用 Q 值方法。有效数字分（至少两位有效数字）至关重要：答案如 0.71 MeV 或 0.710 MeV 只有在写明单位时才被接受。

5. Waves and Optics – Marking Points | 波动与光学——评分点

The waves section of the January 2018 paper centred on a diffraction grating experiment. Candidates were given the grating spacing d and asked to calculate the angle of the second-order maximum for light of wavelength 590 nm. The relevant equation from the data sheet is:

2018年1月试卷的波动部分围绕衍射光栅实验展开。题目给出光栅间距 d，要求计算波长为 590 nm 的光产生二级极大时的角度。数据表中相关公式为：

nλ = d sin θ

The mark scheme explicitly required the substitution step: sin θ = (2 × 590 × 10⁻⁹) / (1.67 × 10⁻⁶). One mark was for the substitution, one for the rearrangement, and one for the final answer. Students who lost marks did so by failing to convert nanometres to metres or by using n = 1 instead of n = 2.

评分方案明确要求写出代入步骤：sin θ = (2 × 590 × 10⁻⁹) / (1.67 × 10⁻⁶)。代入 1 分、变形 1 分、最终答案 1 分。失分学生多因未将纳米换算为米，或误用 n = 1 而实际应为 n = 2。

The written explanation part asked why a certain order of maximum was not visible. The required answer linked the condition sin θ > 1 with the meaning that the maximum does not exist at any real angle. A strong answer also mentioned that the maximum angular position is limited to 90° from the normal, so any solution with sin θ exceeding 1 is physically impossible.

后面的文字解释题问为何某一级极大无法被观察到。标准答案需要将 sin θ > 1 这一条件与“该级极大在任何真实角度都不存在”联系起来。高分答案还会提到，最大角位置受限于法线方向 90°，因此凡使 sin θ 超过 1 的解在物理上都不可能。

Finally, a stationary wave question asked candidates to define a node. The mark scheme accepted: ‘a point along the wave where the amplitude is zero at all times’. Two marks were given for a definition that included both zero amplitude and permanence in time; one mark for simply ‘a point of zero displacement’ failed because displacement is zero only momentarily for points that are not nodes.

最后，驻波问题要求定义波节。评分方案接受：“波上振幅始终为零的点”。能够同时包含“振幅为零”和“时间上恒定”两个要素的定义可得 2 分；只写“位移为零的点”只得 1 分，因为非波节的点其位移只是瞬间为零。

6. Mechanics – Marking Points | 力学——评分点

The mechanics question on the January 2018 paper used a projectile launched horizontally from a cliff. The mark scheme awarded marks in a strict chain: resolving the initial vertical velocity (zero for horizontal launch), applying s = ut + ½at², and then combining horizontal motion with v = s/t.

2018年1月试卷的力学题涉及从悬崖水平抛出的抛体运动。评分方案按严格链条给分：先分解出竖直初速度（水平抛出时为零），再应用 s = ut + ½at²，最后结合水平方向运动使用 v = s/t。

s_y = ½gt² → t = √(2h/g)

Marks were given for selecting the correct SUVAT equation and for substituting g = 9.81 m s⁻² (or 9.8 m s⁻² — both were accepted). The final mark in part (a) was for the horizontal distance, which required an explicit statement that horizontal velocity remains constant because there is no horizontal acceleration (air resistance neglected).

选择正确的 SUVAT 方程并代入 g = 9.81 m s⁻²（9.8 m s⁻² 也可）即可得分。第 (a) 问的最后一分属于水平距离，这一步需要明确表述：由于忽略空气阻力，水平方向无加速度，水平速度保持不变。

A subsequent part of the same question asked candidates to determine the velocity of the projectile just before impact. The mark scheme required a vector answer: both magnitude and direction. Magnitude was found from v = √(v_x² + v_y²) and direction from tan θ = v_y / v_x. Many candidates lost the angle mark because they quoted the angle relative to the horizontal without stating it clearly, or wrote the angle below the horizontal but not the reference line.

同一题的后半部分要求确定抛体落地前瞬间的速度。评分方案要求矢量回答：必须包含大小和方向。大小由 v = √(v_x² + v_y²) 得出，方向由 tan θ = v_y / v_x 得出。许多考生因未明确表述角度是相对水平面的夹角，或只写了“水平下方”却未写明参考线而失去方向分。

7. Materials and Young Modulus | 材料与杨氏模量

The materials question examined the Young modulus experiment. Candidates were expected to identify the correct equipment (micrometer or vernier calliper) and to explain why a long wire is used: it produces a larger extension for a given strain, reducing percentage uncertainty. The mark scheme gave credit for ‘larger extension, so smaller percentage error in measurement’.

材料题考查杨氏模量实验。考生需要指出正确的测量工具（千分尺或游标卡尺），并解释为何使用长金属丝：在给定应变下能产生更大伸长量，从而减小百分比不确定度。评分方案认可“伸长量更大，因此测量误差百分比更小”的表述。

The calculation part gave a force-extension graph and required the Young modulus. The mark scheme required: convert extension to strain using e/l, convert force to stress using F/A, then compute stress/strain. The key marking point was the use of the gradient of the graph, because E = (F/A) ÷ (e/l) = (F/e) × (l/A), where F/e is the gradient.

计算部分给出一张力-伸长量图，要求计算杨氏模量。评分方案要求：用 e/l 将伸长量转化为应变，用 F/A 将力转化为应力，然后计算应力/应变。关键得分点在于使用图的斜率，因为 E = (F/A) ÷ (e/l) = (F/e) × (l/A)，其中 F/e 即为斜率。

The final part of this question asked for one improvement to the experiment. The mark scheme accepted several alternatives: using a thinner wire, using a travelling microscope instead of a metre ruler to measure the extension, ensuring the wire is taut with no kinks, or applying small loads first to remove any permanent stretch. Crucially, the answer had to be specific to the measurement being made — a vague answer such as ‘be more accurate’ earned no marks.

该题最后一部分要求提出一项实验改进。评分方案接受多种答案：使用更细的金属丝、用移测显微镜代替米尺测量伸长量、确保金属丝绷直无弯曲、或先施加小载荷消除永久拉伸。关键在于，答案必须针对具体测量环节——“提高精度”这类笼统表述不得分。

8. Electricity – Circuits and Resistivity | 电学——电路与电阻率

The electricity section of the paper tested resistivity and internal resistance in two separate questions. The resistivity question required the equation R = ρL/A and the substitution of measured values. A common trap in the mark scheme: when the wire diameter was given in millimetres, candidates had to halve it to obtain the radius and then convert to metres before using πr². Each of these steps carried a separate mark.

试卷电学部分通过两道独立的题目分别考查电阻率和内电阻。电阻率题要求使用公式 R = ρL/A 并代入测量值。评分方案中的一个常见陷阱是：题目给出的金属丝直径为毫米，考生必须先取半得到半径，再换算为米后用 πr² 求截面积。每一步骤各占一分的分值。

ρ = RA / L = Rπr² / L

The internal resistance question used a simple circuit with a cell, a variable resistor, and a voltmeter across the terminals. Candidates were asked to sketch a graph of terminal potential difference against current and use it to determine E and r. The mark scheme’s graph requirements were strict: terminal p.d. V on the y-axis, current I on the x-axis, a straight line with negative gradient, and an intercept on the V-axis equal to EMF E.

内电阻题使用了一个简单电路：一个电池、一个可变电阻和一个连接在电池两端的电压表。考生被要求绘制端电压关于电流的图线，并用它确定 E 和 r。评分方案对作图要求极为严格：纵轴为端电压 V、横轴为电流 I、直线斜率为负、与 V 轴的交点等于电动势 E。

The calculation that followed used V = E − Ir. To earn full marks, candidates had to state the equation first, then substitute the intercept value for E and the gradient value for r. The mark scheme noted that candidates who rearranged incorrectly — writing V = E + Ir — gave a positive gradient and lost all three calculation marks.

后续计算使用 V = E − Ir。要获得满分，考生必须先写出方程，然后用截距值替代 E、用斜率值替代 r。评分方案特别指出，那些错误变形为 V = E + Ir 的考生画出了正斜率，从而丢掉了全部 3 个计算分。

9. Practical Skills and Uncertainties | 实验技能与不确定度

Although Paper 1 has no dedicated practical exam, the mark scheme includes at least one question on measurement and uncertainty. In January 2018, this question asked candidates to determine the percentage uncertainty in the diameter of a wire measured with a micrometer reading 0.27 mm with an instrument resolution of 0.01 mm.

尽管试卷1没有单独的实验技能考试，但评分方案通常包含至少一道测量与不确定度的题目。2018年1月，这类题要求考生计算用千分尺测得的金属丝直径的百分比不确定度，读数为 0.27 mm，仪器分辨率为 0.01 mm。

Percentage uncertainty = (0.01 / 0.27) × 100% = 3.7%

The mark scheme accepted answers from 3.7% to 4%. One mark for the absolute uncertainty (0.01 mm), one for correct calculation. The examiner’s comment highlighted that many candidates correctly quoted the formula but divided by the wrong value — using the diameter rather than the radius, or using the measured value after conversion to metres without adjusting the uncertainty accordingly.

评分方案接受 3.7% 到 4% 之间的答案。绝对不确定度（0.01 mm）占 1 分，计算正确占 1 分。考官点评强调，许多考生正确写出了公式，却除错了数值——要么用半径代替直径，要么在换算为米后没有相应调整不确定度。

A second practical-skills question asked why repeating measurements and calculating a mean reduces uncertainty. The mark scheme required the idea that random errors are reduced, not systematic errors. A complete answer also stated that the mean is closer to the true value, because random errors average out over many trials.

另一道实验技能题询问为什么重复测量并计算平均值可以减少不确定度。评分方案要求答出“随机误差被减少，而非系统误差”。完整答案还需说明平均值更接近真实值，因为多次试验后随机误差相互抵消。

10. Common Errors and Examiner Comments | 常见错误与考官评语

The AQA examiner’s report for January 2018 identified five recurring errors. First, failing to use the correct number of significant figures — the mark scheme expressly awards a sig. fig. mark only when the final answer is consistent with the data given, usually 2 s.f. unless stated otherwise. Second, mixing up units when using equations with derived quantities, especially stress and strain.

AQA 2018年1月考官报告指出了五个反复出现的错误。第一，未使用正确的有效数字——评分方案明确规定，只有当最终答案与所给数据一致时（通常为两位有效数字，除非另有说明）才授予有效数字分。第二，使用含导出量的方程时混淆单位，尤其是应力和应变。

Third, writing equations without the intermediate substitution step. AQA posts mark schemes with a ‘show that’ or ‘substitution’ line — simply writing the final answer with no working is not enough for the marks. Fourth, confusing ‘distance’ and ‘displacement’ in mechanics calculations. Fifth, using i = v/r or reusing a symbol from the question with a different meaning without defining it.

第三，只写方程而不写中间的代入步骤。AQA 评分方案中设有“代入”或“证明”步骤——只写最终答案而没有过程的答题无法获得相应分数。第四，在力学计算中混淆“路程”和“位移”。第五，使用 i = v/r 等符号时未定义含义，或重新使用题目中的符号却赋予不同意义。

The examiner’s report also praised candidates who used the additional space for working even when their final answer was wrong — because method marks were awarded for correct equations and substitutions. Always show your method, even if you are unsure of the final numerical answer.

考官报告同时表扬了那些即使最终答案错误但仍在附加答题区写出过程的考生——因为正确的方程和代入步骤可以获得方法分。即使你对最终数值答案没有把握，也一定要展示你的解题过程。

11. Mark Scheme Conventions You Must Know | 你必须了解的评分方案惯例

AQA mark schemes use specific annotation symbols that are not explained to you in the exam but are crucial for understanding how your paper is marked. The notation ‘ecf’ means ‘error carried forward’: if you make an arithmetic error early in a question but use the correct method afterwards, you still receive the method marks. ‘BOD’ stands for ‘benefit of the doubt’ and is applied to poorly written but not wrong answers. ‘Correct answer only’ appears on multiple-choice and some short-answer questions where no working is needed.

AQA 评分方案使用特定的批注符号——这些符号在试卷上不会向你解释，但对你了解评分方式至关重要。“ecf”意为“错误向前延续”：如果你在题目前期出现计算错误但后续方法正确，你仍可获得方法分。“BOD”意为“疑点利益归考生”，适用于书写潦草但不算错误的答案。“仅正确答案”出现在选择题和部分不需要过程的小题中。

The mark scheme also distinguishes between ‘allow’ and ‘accept’. An answer listed as ‘allow’ is one that the examiner may accept if the candidate’s wording is equivalent but different from the standard mark-scheme line. ‘Accept’ is more restricted: the exact listed answer is required. This is why two students in the same exam often receive different scores despite producing superficially similar answers.

评分方案还区分“allow”和“accept”。标为“allow”的答案表示若考生措辞与标准答案不同但含义等价，考官可接受。而“accept”则更为严格：必须给出列出的确切答案。这就是为什么在同一场考试中，两个表面答案相似的学生可能会得到不同的分数。

Finally, be aware of the ‘consequential marking’ chain: in physics calculations, the total marks for a multi-part question are the sum of independent method marks, so a single error does not cascade into losing every mark. The mark scheme is designed to reward every correct step, not just the final answer.

最后，请注意“连带给分”链：在物理计算中，多部分题目的总分是各独立方法分之和，因此单一错误并不会导致所有分数尽失。评分方案的设计初衷是奖励每一个正确的步骤，而不仅是最終答案。

12. Targeted Revision Strategy | 针对性复习策略

Based on the January 2018 mark scheme pattern, your revision should prioritise numerical fluency and the ability to write definitions precisely. The most heavily weighted skills across the paper were: unit conversion (especially nm to m, mm to m, g to kg), substitution into given equations, and graph interpretation (gradients and intercepts).

基于 2018年1月评分方案的出题规律，你的复习应当优先强化数值运算熟练度和精确定义的能力。全卷中权重最高的技能是：单位换算（尤其是纳米到米、毫米到米、克到千克）、代入给定方程，以及图线解读（斜率和截距）。

Memorise the exact wording of key definitions: node, antinode, Young modulus, resistivity, internal resistance, and EMF. 熟记关键定义的准确措辞：波节、波腹、杨氏模量、电阻率、内电阻和电动势。
For equations with multiple steps, practise writing the equation, substituting, then simplifying. 对于多步骤方程，练习先写方程、再代入、然后化简的顺序。
Use past paper mark schemes to build a personal checklist of command words and the marks attached to each step. 用往年评分方案建立你自己的指令词清单，并标注每个步骤的分值。
Practise drawing the four standard graphs: V–I for a cell, force–extension, stress–strain, and I–V characteristics for a filament lamp. 练习绘制四类标准图线：电池的 V–I 图、力-伸长量图、应力-应变图，以及白炽灯的 I–V 特性曲线。

The January 2018 paper is representative of the AS specification’s emphasis on clear method and precise language. By studying the mark scheme as a set of instructions for how to communicate physics, rather than as a list of right answers, you will convert your existing knowledge into higher examination scores.

2018年1月试卷很好地代表了 AS 考纲对清晰方法和精准语言的重视。将评分方案视为一套“如何表述物理”的指令，而不是一排标准答案，你就能把已有的知识转化为更高的考试分数。

For further practice, work through the May–June series papers from the same specification year and compare your written answers against the mark scheme lines, focusing on where marks were actually awarded rather than where you think they should be awarded.

如需进一步练习，请同步完成同年 5–6 月考季的试卷，并将你的书面答案与评分方案逐行对照，重点关注分数实际授予的位置，而不是你认为应该授予的位置。

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AQA AS Physics Paper 1 January 2018 Markscheme Analysis | AQA AS 物理试卷1 2018年1月评分标准分析