IGCSE CIE Physics: High-Frequency Key Points Summary | IGCSE CIE 物理高频考点总结

📚 IGCSE CIE Physics: High-Frequency Key Points Summary | IGCSE CIE 物理高频考点总结

This article summarises the most frequently examined topics in IGCSE CIE Physics, providing essential concepts, key formulas, and common pitfalls. It is designed as a revision guide to boost confidence before the exam.

本文总结了 IGCSE CIE 物理考试中最高频的考点，提供核心概念、关键公式和常见错误，是一份助你考前冲刺的复习指南。

1. Motion, Speed and Acceleration | 运动、速度和加速度

Speed is the distance travelled per unit time: v = s / t. Velocity is speed in a given direction. Acceleration is the rate of change of velocity: a = (v – u) / t. The gradient of a distance–time graph gives speed; the area under a speed–time graph gives distance travelled, and its gradient gives acceleration.

速度是单位时间内通过的距离：v = s / t。速率是带有方向的速度。加速度是速度的变化率：a = (v – u) / t。距离–时间图的斜率表示速度；速度–时间图下的面积表示通过的距离，斜率表示加速度。

Free fall and terminal velocity are also key. When an object falls through a fluid, air resistance increases with speed until the resultant force becomes zero and terminal velocity is reached. The object then falls at constant speed.

自由落体和终端速度也是重点。物体在流体中下落时，空气阻力随速度增加而增大，直到合力为零，达到终端速度，此后物体以恒定速度下落。

2. Forces and Newton’s Laws | 力与牛顿运动定律

Newton’s First Law states that an object remains at rest or in uniform motion unless acted upon by a resultant force. Inertia is the tendency of an object to resist changes in motion. Newton’s Second Law gives the relationship F = m a, where F is the resultant force, m is mass, and a is acceleration. Newton’s Third Law states that every action has an equal and opposite reaction.

牛顿第一定律指出，物体在没有合力作用时，保持静止或匀速直线运动状态。惯性是物体抵抗运动状态变化的性质。牛顿第二定律表达为 F = m a，其中F为合力，m为质量，a为加速度。牛顿第三定律表明，每一个作用力都有一个等大、反向的反作用力。

Friction, air resistance, and the concept of balanced/unbalanced forces are frequently tested. Remember to consider all forces acting, especially weight and normal contact force. Free‑body diagrams help visualise force interactions.

摩擦力、空气阻力以及平衡/不平衡力的概念也常考。务必考虑所有作用力，尤其是重力和支持力。隔离体受力图有助于直观分析力的作用。

3. Work, Energy and Power | 功、能与功率

Work done is the product of force and distance moved in the direction of the force: W = F d. Energy is the capacity to do work. Kinetic energy is KE = ½ m v², and gravitational potential energy is GPE = m g h. The principle of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.

功等于力与沿力方向移动距离的乘积：W = F d。能量是做功的能力。动能为 KE = ½ m v²，重力势能为 GPE = m g h。能量守恒定律指出，能量不能被创造或消灭，只能被转移或转化。

Power is the rate of doing work or transferring energy: P = W / t or P = E / t. Efficiency is calculated as (useful energy output / total energy input) × 100%. Sankey diagrams are used to represent energy transfers and waste energy.

功率是做功或能量转移的速率：P = W / t 或 P = E / t。效率的计算公式为 (有用能量输出 / 总能量输入) × 100%。桑基图用于表示能量转移和浪费的能量。

4. Pressure and Density | 压强与密度

Pressure is defined as force per unit area: p = F / A. The unit is pascal (Pa), where 1 Pa = 1 N m⁻². Pressure in a liquid increases with depth and density, and acts equally in all directions: p = h ρ g, where h is depth, ρ is density, and g is gravitational field strength.

压强定义为力与受力面积之比：p = F / A。单位为帕斯卡 (Pa)，1 Pa = 1 N m⁻²。液体压强随深度和密度增加而增大，并且在各个方向均等作用：p = h ρ g，其中h为深度，ρ为密度，g为重力场强度。

Density is mass per unit volume: ρ = m / V. The manometer and barometer are common instruments to measure pressure. The hydraulic press is an application of Pascal’s principle, where a small force on a small area can produce a large force on a large area due to equal pressure transmission.

密度是质量与体积之比：ρ = m / V。常用测量压强的仪器有U形管压力计和气压计。液压机是帕斯卡原理的应用，由于压强等量传递，小活塞上的小力可在大活塞上产生大的力。

5. Thermal Physics and Heat Transfer | 热学与热传递

The three methods of heat transfer are conduction, convection and radiation. Conduction occurs mainly in solids through particle vibration and free electrons. Convection occurs in fluids (liquids and gases) due to density changes causing circulation currents. Thermal radiation is infrared electromagnetic waves that can travel through a vacuum.

热传递的三种方式是传导、对流和辐射。传导主要发生在固体中，通过粒子振动和自由电子传递。对流发生在流体（液体和气体）中，由于密度变化引起环流。热辐射是以红外电磁波形式传播，能在真空中进行。

Specific heat capacity is the energy required to raise the temperature of 1 kg of a substance by 1 °C: Q = m c Δθ. Specific latent heat of fusion/vaporisation is the energy needed to change 1 kg of a substance between solid/liquid or liquid/gas without temperature change: Q = m L. Pay attention to experimental methods using a heater and joulemeter.

比热容是使1 kg物质温度升高1 °C所需的能量：Q = m c Δθ。比潜热（熔化潜热/汽化潜热）是使1 kg物质在固液或液气间相变而不改变温度所需的能量：Q = m L。需注意使用电加热器和焦耳计的实验方法。

6. Waves: Properties and Behaviour | 波的特性与行为

Waves transfer energy without transferring matter. Transverse waves have oscillations perpendicular to the direction of energy transfer (e.g. light, water waves). Longitudinal waves have oscillations parallel to the direction of energy transfer (e.g. sound). Key wave quantities: wavelength λ, frequency f, amplitude and period T. The wave equation is v = f λ.

波传递能量而不传递物质。横波的振动方向与能量传递方向垂直（如光波、水波）。纵波的振动方向与能量传递方向平行（如声波）。关键波的量：波长λ、频率f、振幅和周期T。波速公式为 v = f λ。

Reflection, refraction and diffraction are wave behaviours. Refraction is the change in speed and direction when a wave enters a new medium. Diffraction is the spreading of waves around obstacles or through gaps, most noticeable when the gap size is comparable to the wavelength. The ripple tank is the standard demonstration apparatus.

反射、折射和衍射是波的行为。折射是波进入新介质时速度和方向的改变。衍射是波绕过障碍物或穿过狭缝时扩散的现象，当狭缝大小与波长相近时最明显。纹波槽是标准的演示装置。

7. Optics: Reflection and Refraction | 光学：反射与折射

The law of reflection states that the angle of incidence equals the angle of reflection, and both lie in the same plane as the normal. Plane mirror images are virtual, upright, laterally inverted and the same size as the object. For refraction, Snell’s law links the angles and refractive index: n = sin i / sin r. Total internal reflection occurs when light travels from a denser to a less dense medium at an angle of incidence greater than the critical angle.

反射定律：入射角等于反射角，且入射光线、反射光线与法线在同一平面内。平面镜成像为虚像、正立、横向倒置且与物体等大。折射遵循折射定律，折射率 n = sin i / sin r。当光从光密介质射向光疏介质，且入射角大于临界角时，发生全内反射。

Total internal reflection is used in optical fibres and prisms in periscopes. The critical angle c is given by n = 1 / sin c. Lenses: converging (convex) lenses produce real, inverted images when the object is beyond the focal point, and virtual, upright images when the object is inside the focal length. Ray diagrams are essential for image formation.

全内反射用于光纤和潜望镜中的棱镜。临界角c满足 n = 1 / sin c。透镜：会聚（凸）透镜在物体位于焦距以外时成倒立实像，在物体位于焦距以内时成正立虚像。光线图对于确定像的位置至关重要。

8. Electric Circuits | 电路

Current is the rate of flow of charge: I = Q / t. It is measured by an ammeter connected in series. Potential difference (voltage) is the energy transferred per unit charge: V = W / Q or V = E / Q. Resistance is the opposition to current: R = V / I, and is measured in ohms (Ω). Ohm’s law applies at constant temperature for a conductor with constant resistance.

电流是电荷流动的速率：I = Q / t，通过串联的电流表测量。电势差（电压）是每单位电荷转移的能量：V = W / Q 或 V = E / Q。电阻是对电流的阻碍：R = V / I，单位为欧姆 (Ω)。欧姆定律适用于恒定温度下电阻不变的导体。

Series circuits: current is the same throughout, resistances add up: R_total = R₁ + R₂ + …, and the supply voltage is divided. Parallel circuits: the current is split, the voltage across each branch is the same, and the combined resistance is given by 1/R_total = 1/R₁ + 1/R₂ + …. Electrical power: P = I V = I² R = V² / R.

串联电路：各处电流相同，总电阻为各电阻之和：R_total = R₁ + R₂ + …，电源电压被分配。并联电路：电流分流，各支路电压相等，总电阻计算为 1/R_total = 1/R₁ + 1/R₂ + …。电功率：P = I V = I² R = V² / R。

9. Electromagnetic Effects | 电磁效应

A magnetic field exists around a permanent magnet and around a current‑carrying conductor. The right‑hand grip rule determines the direction of the magnetic field around a straight wire and a solenoid. An electromagnet is a solenoid with a soft iron core, producing a stronger, adjustable magnetic field. Common applications include relays, electric bells, and circuit breakers.

永磁体周围和载流导体周围都存在磁场。右手螺旋定则用于判断直导线和螺线管周围的磁场方向。电磁铁是带有软铁芯的螺线管，能产生更强且可调节的磁场。常见应用包括继电器、电铃和断路器。

The motor effect: a current‑carrying conductor in a magnetic field experiences a force, given by F = B I L (where B is the magnetic flux density). Fleming’s left‑hand rule gives the force direction. This is the principle behind the DC motor. Electromagnetic induction: a changing magnetic field near a conductor induces an e.m.f., as used in generators and transformers. The transformer equation is V_p / V_s = N_p / N_s, working only with AC.

电动机效应：磁场中的载流导体会受到力，其大小为 F = B I L (B为磁通密度)。弗莱明左手定则给出受力方向。这是直流电动机的原理。电磁感应：导体附近的磁场变化会感应出电动势，用于发电机和变压器。变压器公式为 V_p / V_s = N_p / N_s，仅在交流电下工作。

10. Radioactivity and Atomic Physics | 放射性与原子物理

An atom consists of a nucleus containing protons and neutrons, surrounded by electrons. The proton number (atomic number) defines the element; the nucleon number (mass number) is the sum of protons and neutrons. Isotopes have the same proton number but different nucleon numbers.

原子由包含质子和中子的原子核及周围的电子组成。质子数（原子序数）决定元素种类；核子数（质量数）是质子数与中子数之和。同位素质子数相同，但核子数不同。

Radioactive decay is the spontaneous emission of α‑particles (helium nuclei), β‑particles (fast electrons) or γ‑rays (electromagnetic waves). Their relative ionising and penetrating powers differ. The half‑life is the time for half the radioactive nuclei in a sample to decay. Background radiation comes from natural and artificial sources. The equation for nuclear decay must balance mass and atomic numbers on both sides.

放射性衰变是原子核自发地发射α粒子（氦核）、β粒子（高速电子）或γ射线（电磁波）。它们的电离能力和穿透本领各不相同。半衰期是样品中一半放射性原子核发生衰变所需的时间。本底辐射来自自然和人工源。核衰变方程两边必须质量数和原子序数守恒。

Published by TutorHao | Physics Revision Series | aleveler.com

更多咨询请联系16621398022（同微信）