📚 Edexcel / OCR A Level Physics June 2023 Paper 1 | Edexcel / OCR A Level 物理 2023年6月卷1 复习指南
Paper 1 in Edexcel and OCR A Level Physics is the first written paper covering core principles: mechanics, materials, electricity, waves and quantum physics. This revision guide reviews the key ideas and question styles that appeared in the June 2023 series, so you can focus on high-yield skills.
Edexcel 与 OCR A Level 物理的 Paper 1 通常是首份笔试，覆盖力学、材料、电学、波与量子物理等核心内容。本文回顾 2023 年 6 月考试系列中反复出现的关键概念与题型，帮助你集中训练高分技能。
1. Mechanics: Motion and SUVAT | 力学：运动与 SUVAT 方程
The SUVAT equations only apply to constant acceleration in a straight line. Identify the known quantities before selecting an equation. The standard forms are:
SUVAT 方程只适用于直线匀加速运动。先标出已知量，再选择方程。标准形式为：
v = u + at; s = ut + ½at²; v² = u² + 2as
In June 2023 Paper 1, many questions combined SUVAT with projectile motion, where horizontal and vertical components are treated independently.
2023 年 6 月卷 1 中不少题目把 SUVAT 与抛体运动结合，水平和竖直分量必须独立处理。
Remember to use g = 9.81 m s⁻² and decide a sign convention for upward or downward motion.
记住取 g = 9.81 m s⁻²，并先规定向上或向下为正方向。
2. Forces, Energy and Momentum | 力、能量与动量
Newton' s that resultant force F = ma, while momentum is p = mv. The impulse-momentum relation is:
牛顿第二定律指出合力 F = ma，动量定义为 p = mv。冲量-动量关系为：
FΔt = Δp = mv - mu
Conservation of momentum applies when no external resultant force acts. In collisions, kinetic energy is only conserved in perfectly elastic collisions.
当系统所受外力的合力为零时动量守恒。碰撞中只有完全弹性碰撞才同时守恒动能。
Work done is W = Fs cosθ. Power is the rate of doing work:
功的计算为 W = Fs cosθ。功率是做功的快慢：
P = W/t = Fv
Typical Paper 1 questions ask you to compare kinetic energy before and after an inelastic collision or to calculate recoil velocity.
卷 1 典型题目常要求比较非弹性碰撞前后的动能，或计算反冲速度。
3. Materials: Stress, Strain and Young Modulus | 材料：应力、应变与杨氏模量
σ = F/A, measured in Pa. Strain is extension per original length: ε = ΔL/L, with no units.
应力定义为单位面积的力：σ = F/A，单位是 Pa。应变定义为伸长量与原长之比：ε = ΔL/L，无量纲。
E = σ/ε = FL/(AΔL)
Young modulus measures stiffness and is constant only within the linear elastic region. A stress-strain graph shows the limit of proportionality, elastic limit, yield point and ultimate tensile strength for ductile materials.
杨氏模量反映材料的刚度，只在弹性线性区内为常数。应力-应变曲线可显示比例极限、弹性极限、屈服点和抗拉强度（韧性材料）。
Be careful with units: area should be in m², not cm² or mm². This is a common source of error.
注意单位换算：面积必须用 m²，而非 cm² 或 mm²，这是常见失分点。
4. Electric Current and Circuits | 电流与电路
e rate of flow of charge: I = ΔQ/Δt. Conventional current flows from positive to negative.
电流是电荷流动的速率：I = ΔQ/Δt。约定电流方向为正电荷流向负电荷。
Charge conservation gives Kirchhoff's first law: the sum of currents entering a junction equals the sum leaving it.
电荷守恒对应基尔霍夫第一定律：流入节点的电流之和等于流出节点之和。
Energy conservation gives Kirchhoff's second law: around any closed loop, the sum of e.m.f.s equals the sum of potential differences.
能量守恒对应基尔霍夫第二定律：沿任意闭合回路，电动势之和等于电势差之和。
Series and parallel resistance equations are:
电阻串联与并联公式为：
Rtotal = R₁ + R₂ + ... ; 1/Rtotal = 1/R₁ + 1/R₂ + ...
questions combine these rules with internal resistance r, where terminal p.d. V = E - Ir.
许多电路题会结合内阻 r 考查，端电压 V = E - Ir。
5. Resistance and I-V Characteristics | 电阻与 I-V 特性曲线
Ohm' ic conductor at constant temperature. The I-V graph is a straight line through the origin.
欧姆定律说明对恒温欧姆导体有 V = IR。其 I-V 图是一条过原点的直线。
A filament lamp curves because resistance increases with temperature. A diode has very high resistance in reverse and conducts in forward bias above about 0.6 V.
白炽灯的 I-V 曲线弯曲，因为温度升高电阻增大。二极管反向电阻很大，正向偏压约 0.6 V 以上导通。
Resistivity links resistance to geometry:
电阻率把电阻与几何尺寸联系起来：
R = ρL/A
Potential divider questions often ask for output voltage:
分压器题目常考输出电压：
Vout = Vin × R₂/(R₁ + R₂)
In sensor circuits, one resistor may be an LDR or thermistor. Check how its resistance changes with light intensity or temperature.
在传感器电路中，一个电阻可能是光敏电阻或热敏电阻，需注意其阻值随光强或温度的变化。
6. Wave Properties and Superposition | 波的性质与叠加
A progressive wave transfers energy without transferring matter. The wave speed equation is:
行波传播能量但不传播物质。波速公式为：
v = fλ
Transverse waves oscillate perpendicular to energy transfer; longitudinal waves oscillate parallel. Sound is longitudinal, light is transverse.
横波的振动方向与能量传播方向垂直；纵波平行。声波是纵波，光是横波。
When two waves meet, superposition applies. Constructive interference occurs when path difference is nλ; destructive when path difference is (n + ½)λ.
两列波相遇时发生叠加。当波程差为 nλ 时产生相长干涉；为 (n + ½)λ 时产生相消干涉。
Phase difference is measured in radians or degrees. A path difference of λ corresponds to a phase difference of 2π rad or 360°.
相位差以弧度或度表示。波程差为 λ 对应相位差 2π rad 或 360°。
7. Standing Waves and Harmonics | 驻波与谐波
Standing waves form when two identical waves travel in opposite directions. Nodes have zero displacement, antinodes have maximum amplitude.
两列相同的波相向传播时形成驻波。波节处位移为零，波腹处振幅最大。
For a string fixed at both ends, the nth harmonic frequency is:
两端固定的弦，第 n 次谐波频率为：
