📚 AQA A-Level Physics June 2018 Paper 1 Mark Scheme Explained | AQA A-level 物理 2018年6月试卷1 评分标准详解
The June 2018 AQA A-level Physics Paper 1 (7408/1) mark scheme is an essential revision resource because it shows exactly how marks are awarded for equations, substitutions, diagrams, and explanations. This article unpacks the structure of that mark scheme, highlights the most common mistakes students make, and explains how to use the wording of the mark scheme to maximise your score.
2018年6月AQA A-level物理试卷1（7408/1）的评分标准是复习时必不可少的资源，因为它精确展示了方程、代入、图像和解释分别如何给分。本文将解析该评分标准的结构，指出学生最常见的失误，并讲解如何利用评分标准的措辞来最大化得分。
1. Understanding the Structure of Paper 1 | 理解试卷1的结构
Paper 1 covers AQA Topics 1–5: measurements and their errors, particles and radiation, waves, mechanics and materials, and electricity. The paper lasts 2 hours and is worth 100 marks in total. Section A contains 30 multiple-choice questions, while Section B contains structured questions worth 70 marks, including extended-response items.
试卷1考查AQA主题1至5：测量与误差、粒子与辐射、波、力学与材料、电学。考试时长2小时，满分100分。A部分包含30道选择题，B部分为70分的结构化简答题，其中包括扩展论述题。
The mark scheme uses the codes AO1, AO2, and AO3. AO1 questions test recall of knowledge, AO2 asks you to apply knowledge to familiar or novel contexts, and AO3 tests experimental skills, including data analysis and evaluation. Knowing which skill is being tested helps you decide how much detail to give.
评分标准使用AO1、AO2、AO3三种代码。AO1考查知识记忆，AO2要求将知识应用于熟悉或新颖情境，AO3考查实验技能，包括数据分析和评估。清楚知道考查哪种技能，有助于你判断答案需要多详细。
2. Multiple-Choice Questions: How the Mark Scheme Thinks | 选择题：评分标准的逻辑
Multiple-choice questions in the June 2018 paper often reward a correct equation chosen before any calculation. If you do not write the equation, you can still earn the mark for the final letter, but writing the equation helps you avoid sign and unit errors.
2018年6月试卷中的选择题通常先考你是否选对了方程，然后才考计算。即使不写方程，选对字母也能得分，但写出方程能帮助你避免符号和单位错误。
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Use units to eliminate options. For example, a gradient might be in N m⁻¹ rather than N.
利用单位排除选项。例如，斜率的单位可能是N m⁻¹，而不是N。
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Check powers of ten carefully. A value of 0.025 m could be written as 2.5 × 10⁻² m.
仔细检查十的幂次。0.025 m可以写成2.5 × 10⁻² m。
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If a question asks for ‘magnitude’, ignore the sign of your answer.
如果题目要求“大小”，就不要管答案的符号。
3. Mechanics: Equations First, Substitution Second | 力学：先写方程，再代入数值
In mechanics questions, the mark scheme typically awards one mark for the correct equation, one for correct substitution, and one for the final answer with the correct unit. For example, for projectile motion, writing v² = u² + 2as can earn the equation mark even if you later substitute wrong numbers.
在力学题中，评分标准通常给“正确方程”一分、“正确代入”一分、“正确结果和单位”一分。例如，对于抛体运动，写出v² = u² + 2as就算方程分到手，之后即使代入错误，也能保住这一分。
v² = u² + 2as
When a question involves two dimensions, split the motion into horizontal and vertical components. The mark scheme often has a separate mark for recognising that the horizontal velocity is constant, and another for using acceleration due to gravity in the vertical direction.
当问题涉及二维运动时，要把运动分解为水平方向和竖直方向。评分标准往往单独给“水平速度恒定”一分，再给“竖直方向使用重力加速度”一分。
4. Materials and the Young Modulus | 材料性质与杨氏模量
A common question in the June 2018 paper involved calculating the Young modulus from a stress-strain graph. The mark scheme expects you to use the gradient of the straight-line region, not the stress and strain of a single data point.
2018年6月试卷中常见的一类题是利用应力-应变图的斜率计算杨氏模量。评分标准要求你使用直线区域的斜率，而不是某单个数据点的应力和应变。
Young modulus = gradient of stress-strain graph = σ / ε
Stress is defined as force per unit area, and strain is the fractional increase in length. You must convert all lengths to metres and all areas to m² before substituting. The mark scheme often has a dedicated mark for the conversion of mm² to m².
应力定义为单位面积上的力，应变是长度的相对变化。代入前必须把所有长度换算为米，面积换算为m²。评分标准通常为mm²到m²的换算单独设一分。
| Area unit | Conversion to m² | Common mistake |
|---|---|---|
| 1 cm² | 1 × 10⁻⁴ m² | Writing 1 × 10⁻² m² |
| 1 mm² | 1 × 10⁻⁶ m² | Writing 1 × 10⁻³ m² |
5. Electricity: EMF, Internal Resistance, and Graphs | 电学：电动势、内阻与图像
For circuits involving cells and internal resistance, the mark scheme uses the equation E = I(R + r), where E is the e.m.f., I is the current, R is the external resistance, and r is the internal resistance. Many students lose marks by writing only E = IR, which ignores the internal resistance entirely.
对于包含电池内阻的电路，评分标准使用方程E = I(R + r)，其中E是电动势，I是电流，R是外电阻，r是内阻。许多学生只写E = IR，完全忽略了内阻，因此丢分。
E = I(R + r) or V = E − Ir
If the question gives a graph of terminal potential difference V against current I, the y-intercept equals the e.m.f. E, and the gradient equals −r. In the mark scheme, you must state these relationships clearly to obtain the graph-interpretation marks.
如果题目给出端电压V随电流I变化的图像，纵截距等于电动势E，斜率等于−r。在评分标准中，你必须清楚写出这些关系，才能获得图像解读分。
6. Particle Physics: Quarks, Leptons, and Beta Decay | 粒子物理：夸克、轻子与β衰变
Particle physics questions in the June 2018 paper tested conservation laws. In β⁻ decay, a neutron changes into a proton, an electron, and an anti-neutrino. The quark-level equation is d → u + e⁻ + anti-ν.
2018年6月试卷中的粒子物理题考查守恒定律。在β⁻衰变中，中子变成质子、电子和反中微子。夸克层面的方程为d → u + e⁻ + 反中微子。
n → p + e⁻ + anti-ν (d → u + e⁻ + anti-ν)
The mark scheme awards separate marks for charge conservation, baryon number conservation, and lepton number conservation. For β⁻ decay, charge is conserved because the total charge before and after the interaction is zero. Baryon number is conserved because n and p are both baryons, while d and u are both quarks.
评分标准分别给电荷守恒、重子数守恒和轻子数守恒赋分。对于β⁻衰变，前后总电荷为零，因此电荷守恒。中子和质子都是重子，所以重子数守恒；d夸克和u夸克也都是夸克，因此夸克层也满足重子数守恒。
7. Waves and Stationary Waves | 波与驻波
Stationary wave questions often ask about nodes, antinodes, and harmonic frequencies. For a string fixed at both ends, the frequency of the nth harmonic is fₙ = nv/(2L), where v is the wave speed and L is the length of the string.
驻波题常考查节点、腹点和谐波频率。对于两端固定的弦，第n次谐波的频率为fₙ = nv/(2L)，其中v是波速，L是弦长。
fₙ = nv/(2L)
In your answer, define a node as a point of zero amplitude and an antinode as a point of maximum amplitude. Explain that a stationary wave is formed by the superposition of two waves of the same frequency and amplitude travelling in opposite directions.
在回答中，要把节点定义为振幅为零的点，把腹点定义为振幅最大的点。要解释驻波是由两列频率相同、振幅相同、沿相反方向传播的波叠加形成的。
8. Photoelectric Effect and Quantisation of Energy | 光电效应与能量量子化
The photoelectric effect is one of the most frequently tested A-level topics. The mark scheme requires Einstein’s photoelectric equation, hf = Φ + K_max, where hf is the photon energy, Φ is the work function, and K_max is the maximum kinetic energy of an emitted electron.
光电效应是A-level最常考的考点之一。评分标准要求写出爱因斯坦光电方程：hf = Φ + K_max，其中hf是光子能量，Φ是逸出功，K_max是逸出电子的最大动能。
hf = Φ + K_max
A good written answer will include two key ideas: one photon interacts with one electron, and a photon with frequency below the threshold frequency has insufficient energy to release an electron. If a graph of K_max against frequency is drawn, the gradient is Planck’s constant h and the x-intercept is the threshold frequency f₀.
好的书面答案需要包含两个关键概念：一个光子只与一个电子相互作用；低于阈频率的光子没有足够能量释放电子。如果绘制K_max随频率变化的图像，斜率为普朗克常数h，横截距为阈频率f₀。
9. Uncertainties, Errors, and Practical Skills | 不确定度、误差与实验技能
Practical-based questions in June 2018 Paper 1 tested percentage uncertainty, absolute uncertainty, and the combination of uncertainties. The mark scheme gives one mark for stating the equation: percentage uncertainty = (absolute uncertainty / measured value) × 100%.
2018年6月Paper 1中的实验题考查百分比不确定度、绝对不确定度以及不确定度的合成。评分标准对写出“百分比不确定度 = (绝对不确定度 / 测量值) × 100%”给一分。
percentage uncertainty = (absolute uncertainty / measured value) × 100%
When quantities are added or subtracted, add the absolute uncertainties. When quantities are multiplied or divided, add the percentage uncertainties. If a quantity is raised to the power n, multiply its percentage uncertainty by n.
当物理量相加或相减时，绝对不确定度相加。当物理量相乘或相除时，百分比不确定度相加。如果某个量具有幂指数n，其百分比不确定度变为原来的n倍。
10. Command Words: What the Mark Scheme Expects | 命令词：评分标准到底要什么
AQA mark schemes are sensitive to the command words used in each question. ‘State’ requires a short answer, often one word or one sentence. ‘Calculate’ requires working, and the final answer must include a unit. ‘Determine’ often means you need to obtain a value from a graph or a set of data.
AQA评分标准非常看重题目中的命令词。“State”要求简短回答，通常是一个单词或一句话。“Calculate”必须写出过程，最终答案必须带单位。“Determine”通常表示需要从图像或数据中求出数值。
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‘Show that’ — write down the calculation and conclude with ‘this is close to the stated value’.
“Show that”——写出计算过程，并以“这个数值接近题目给定值”作为结论。
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‘Explain’ — provide two or three distinct physics ideas in logical order.
“Explain”——按逻辑顺序给出两到三个不同的物理要点。Published by TutorHao | Physics Revision Series | aleveler.com
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