📚 Year 10 OCR Physics: Core Knowledge Review | Year 10 OCR 物理：核心知识点梳理
This article brings together the fundamental ideas from the early units of OCR GCSE Physics, covering matter, forces, electricity and magnetism. It is designed as a clear, bilingual revision guide to help you check your understanding and practise using the key equations and concepts.
本文汇集了 OCR GCSE 物理前期单元的核心思想，涵盖物态、力、电学与磁学。文章以清晰的中英双语复习指南形式呈现，帮助你检查理解并练习关键公式与概念的应用。
1. Particle Model and Density | 粒子模型与密度
All substances are made of tiny particles. In solids the particles vibrate in fixed positions, in liquids they can slide past each other, and in gases they move rapidly in random directions. This model explains why solids keep their shape, liquids flow and gases spread out.
所有物质都由微小粒子组成。固体中的粒子在固定位置上振动，液体中的粒子可以彼此滑动，气体中的粒子朝各个方向快速随机运动。这一模型解释了为何固体能保持形状、液体会流动、气体会扩散。
Density is the mass per unit volume of a material. It is calculated using the formula shown below and measured in kilograms per cubic metre (kg m⁻³). Regular solids can be measured with a ruler and balance; irregular solids are often immersed in water using a displacement can.
密度是单位体积物质的质量，可用下面的公式计算，单位为千克每立方米 (kg m⁻³)。规则固体可用尺子和天平测量，不规则固体通常借助排水法得到体积。
ρ = m / V
The particle arrangement also affects density – most solids are denser than liquids, and gases have very low densities because the particles are far apart.
粒子排列方式同样影响密度——多数固体的密度大于液体，而气体因为粒子间距大，密度非常低。
2. Specific Heat Capacity and Latent Heat | 比热容与潜热
Internal energy is the total kinetic and potential energy stored in the particles of a system. Heating increases the internal energy, which can raise the temperature or cause a change of state. Temperature is a measure of the average kinetic energy of the particles.
内能是系统粒子储存的动能与势能总和。加热会增加内能，这可以提高温度或引起物态变化。温度是粒子平均动能的量度。
Specific heat capacity is the energy needed to raise the temperature of 1 kg of a substance by 1 °C. The equation is given below. Water has a high specific heat capacity, which makes it useful for thermal storage and cooling.
比热容是使 1 kg 物质的温度升高 1 °C 所需的能量，方程如下。水的比热容很大，因此在储热和冷却方面用途广泛。
ΔE = m c Δθ
) and vaporisation (boiling) are calculated using E = m L. Flat sections on a heating graph show where latent heat is being transferred.
潜热是物态变化过程中吸收或释放的能量，温度不发生变化。熔化比潜热和汽化比潜热用 E = m L 计算。加热曲线上的平台区域表示潜热正在传递。
3. Describing Motion | 描述运动
irection. Acceleration is the rate of change of velocity and can be calculated with a = (v – u) / t.
描述运动需要用到标量和矢量。距离和速率是标量，位移和速度是包含方向的矢量。加速度是速度变化的快慢，可用 a = (v – u) / t 计算。
Distance–time graphs show how far an object has travelled. A straight, sloping line indicates constant speed; the gradient gives the speed. Velocity–time graphs give acceleration from the gradient and displacement from the area under the graph.
距离-时间图显示物体运动的远近。一条倾斜直线代表匀速运动，斜率给出速率。速度-时间图中，斜率表示加速度，图线下的面积表示位移。
= ut + ½ at² and v² = u² + 2as. These equations only apply when acceleration is constant.
对于匀加速运动，使用三个运动方程：v = u + at，s = ut + ½ at² 和 v² = u² + 2as。这些方程仅适用于加速度恒定的情况。
4. Newton's Laws of Motion | 牛顿运动定律
alled inertia. Newton’s Second Law relates resultant force, mass and acceleration: F = ma.
牛顿第一定律指出，除非受到合外力作用，物体将保持静止或匀速直线运动状态，这一性质称为惯性。牛顿第二定律将合外力、质量和加速度联系起来：F = ma。
Newton’s Third Law describes force pairs: when one object exerts a force on another, the second exerts an equal and opposite force on the first. These forces act on different objects and are of the same type.
牛顿第三定律描述了力对：当一个物体对另一物体施加力时，后者同时对前者施加大小相等、方向相反的力。这两个力作用在不同物体上，且属于同种类型。
he gravitational field strength (9.8 N/kg on Earth). Mass is a measure of the amount of matter and does not change with location.
重量是物体受到的重力，计算公式为 W = mg，其中 g 是引力场强度（地球表面约为 9.8 N/kg）。质量是物质多少的量度，不随地点变化。
5. Momentum | 动量
Momentum is a vector quantity defined as the product of mass and velocity. It is measured in kg m s⁻¹. In a closed system, total momentum is conserved before and after a collision or explosion, allowing us to predict final velocities.
动量是矢量，定义为质量与速度的乘积，单位为 kg m s⁻¹。在孤立系统中，碰撞或爆炸前后的总动量守恒，据此可以预测末速度。
p = m v
d change in momentum, increasing the time of impact reduces the force. Car safety features like airbags, seatbelts and crumple zones use this principle to protect passengers.
力可以表示为动量的变化率：F = Δp / t。在动量变化量一定的情况下，延长碰撞时间可以减小作用力。安全气囊、安全带和溃缩区等汽车安全装置正是利用这一原理来保护乘客。
6. Electrical Charge and Current | 电荷与电流
and is given by I = Q / t, where Q is the charge in coulombs and t is the time in seconds.
电流是电荷的流动。在金属电路中，移动的电荷是电子。电流以安培 (A) 为单位，公式为 I = Q / t，其中 Q 是电荷量（库仑），t 是时间（秒）。
Conventional current flows from positive to negative, opposite to the direction of electron flow. For a current to flow, a circuit must be complete and contain a source of potential difference (voltage).
传统电流方向是从正极流向负极，与电子流动方向相反。电流流动需要完整的回路和电势差（电压）源。
In a series circuit the current is the same everywhere. In a parallel circuit the current from the source splits among the branches and recombines, so the sum of branch currents equals the total current.
在串联电路中，各处电流相等。在并联电路中，干路电流分成若干个支路电流，之后重新汇合，支路电流之和等于总电流。
7. Resistance and Ohm's Law | 电阻与欧姆定律
nt temperature, the current is directly proportional to the potential difference: V = I R.
电阻阻碍电流的流动，单位为欧姆 (Ω)。欧姆定律指出，对于恒定温度下的欧姆导体，电流与电势差成正比：V = I R。
R = V / I
The resistance of a metal wire increases with length, decreases with cross-sectional area, and depends on the material. In a filament lamp the resistance increases as the temperature rises; for a diode current only flows in one direction.
金属导线的电阻随长度增加而增大，随横截面积增大而减小，还与材料有关。灯丝灯泡的电阻随温度升高而增大；二极管只允许电流单向通过。
Resistors can be fixed or variable. A light-dependent resistor (LDR) decreases in resistance as light intensity increases, while a thermistor decreases in resistance as temperature rises – ideal for sensing circuits.
电阻器有固定电阻器与可变电阻器。光敏电阻 (LDR) 的阻值随光照增强而降低，热敏电阻的阻值随温度升高而降低，非常适合用作传感电路元件。
8. Power and Energy in Circuits | 电路中的功率与能量
I² R or P = V² / R for components that obey Ohm’s law. The unit of power is the watt (W).
功率是能量转移的速率。电路中的功率用 P = I V 计算，对于遵守欧姆定律的元件，还可表示为 P = I² R 或 P = V² / R。功率的单位是瓦特 (W)。
ehold electricity bills charge for energy used in kilowatt-hours (kWh). Choosing appliances with a lower power rating reduces energy consumption.
消耗的能量等于功率乘以时间：E = P t = I V t。家庭电费按千瓦时 (kWh) 计费。选择额定功率较低的电器可以降低能耗。
For series circuits, total resistance is the sum of individual resistances: Rtotal = R₁ + R₂ + … estic wiring uses parallel connections so that each appliance receives full mains voltage.
串联电路的总电阻等于各电阻之和：Rtotal = R₁ + R₂ + … 。并联电路中，总电阻的倒数等于各电阻倒数之和。家庭电路采用并联连接，使每个电器都能获得完整的电网电压。
9. Magnetism and Electromagnets | 磁性与电磁铁
Magnets have north and south poles. Like poles repel, unlike poles attract. A magnetic field is the region around a magnet where magnetic forces act; field lines go from north to south. Iron, nickel and cobalt are magnetic materials.
磁体有北极和南极，同极相斥、异极相吸。磁场是磁体周围磁性力作用的区域，磁感线由北极指向南极。铁、镍和钴是磁性材料。
An electromagnet is created by passing a current through a coil of wire, often wrapped around a soft iron core. The magnetic field strength increases with more turns and a larger current. Electromagnets are used in scrapyard cranes, relays and electric bells.
电磁铁由通电线圈制造，通常缠绕在软铁芯上。增加匝数或增大电流可以增强磁场。电磁铁广泛应用于废料场吊车、继电器和电铃。
The direction of the magnetic field around a straight wire can be found using the right-hand grip rule: thumb points in current direction, fingers curl in field direction. For a solenoid, the field is similar to that of a bar magnet.
通电直导线周围的磁场方向可用右手螺旋定则判断：拇指指向电流方向，弯曲的四指指向磁场方向。螺线管的磁场与条形磁铁相似。
10. The Motor Effect | 电动机效应
When a current-carrying conductor is placed in a magnetic field, it experiences a force – this is the motor effect. The force is largest when the current is perpendicular to the field. Fleming’s left-hand rule gives the force direction: thumb (thrust), first finger (field), second finger (current).
通电导体放在磁场中会受到力的作用，这就是电动机效应。当电流方向与磁场方向垂直时，力最大。弗莱明左手定则判断力方向：拇指（推力）、食指（磁场）、中指（电流）。
A DC motor uses a coil in a magnetic field. A split-ring commutator reverses the current every half-turn, ensuring the coil continues to rotate in the same direction. The speed can be increased by using a stronger magnet, more current or more coil turns.
直流电动机利用磁场中的线圈工作。开口环换向器每半圈改变电流方向，使线圈保持同一方向转动。增大磁场强度、电流或线圈匝数都能提高转速。
11. Electromagnetic Induction | 电磁感应
Electromagnetic induction occurs when a conductor cuts magnetic field lines, generating a potential difference. This is the principle behind generators and dynamos. The induced voltage can be increased by using a stronger magnet, moving the conductor faster, or adding more coil turns.
当导体切割磁感线时，会产生电磁感应现象，从而产生电势差。这是发电机和发电机的原理。增强磁场、加快导体运动速度或增加线圈匝数都能提高感应电压。
Fleming’s right-hand rule is used for generators: thumb (motion), first finger (field), second finger (induced current). An alternator uses slip rings to produce alternating current (AC); a dynamo uses a split-ring commutator to produce direct current (DC).
发电机使用弗莱明右手定则：拇指（运动方向）、食指（磁场）、中指（感应电流）。交流发电机利用滑环产生交流电，直流发电机则用开口环换向器输出直流电。
Microphones and loudspeakers also rely on electromagnetic principles. A moving-coil microphone converts sound waves into an electrical signal via induction; a loudspeaker uses the motor effect to turn electrical signals into sound.
话筒和扬声器同样依赖电磁原理。动圈式话筒通过电磁感应将声波转换为电信号；扬声器则利用电动机效应把电信号转换为声音。
Published by TutorHao | Physics Revision Series | aleveler.com
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