📚 Year 10 SQA Physics: Core Knowledge Revision | Year 10 SQA 物理核心知识点梳理
This guide covers the essential topics in Year 10 SQA Physics, helping you build a solid foundation in mechanics, electricity, waves, matter and radiation. Each section presents a key idea in English followed by a Chinese translation, ensuring you grasp both the language and the scientific concepts.
本指南涵盖 Year 10 SQA 物理的核心主题，帮助你打牢力学、电学、波动、物质和辐射的基础。每个小节先用英语阐述关键思想，再配以中文翻译，确保你同时掌握语言表述和科学概念。
1. Scalars and Vectors | 标量与矢量
A scalar quantity has only magnitude (size), whereas a vector quantity has both magnitude and direction. Distance, speed, mass and energy are scalars; displacement, velocity, force and acceleration are vectors.
标量只有大小，而矢量既有大小又有方向。距离、速率、质量和能量是标量；位移、速度、力和加速度是矢量。
When adding vectors, you must consider direction. Two parallel vectors add by simple arithmetic, but perpendicular vectors require the triangle method or Pythagoras' theorem. The resultant of a 3 N force east and a 4 N force north is 5 N at an angle of 53° north of east.
矢量相加时必须考虑方向。两个平行的矢量可直接加减，而相互垂直的矢量需要用三角形法则或勾股定理。3 N 向东的力和 4 N 向北的力的合力大小为 5 N，方向为东偏北 53°。
| Scalars / 标量 | Vectors / 矢量 |
|---|---|
| Distance (d) / 距离 | Displacement (s) / 位移 |
| Speed (v) / 速率 | Velocity (v) / 速度 |
| Mass (m) / 质量 | Weight (W) / 重量 |
| Energy (E) / 能量 | Force (F) / 力 |
2. Speed, Velocity and Acceleration | 速率、速度与加速度
ion. Acceleration is the rate of change of velocity: a = Δv ÷ t, where Δv = final velocity – initial velocity (v – u).
平均速率是总路程除以时间：v = d ÷ t。速度是单位时间内的位移并带有方向。加速度是速度的变化率：a = Δv ÷ t，其中 Δv = 末速度 – 初速度 (v – u)。
Motion can be represented on graphs. A distance–time graph shows a constant slope for steady speed; a steeper slope means higher speed. A velocity–time graph shows acceleration as the slope, and the area under the graph gives displacement.
运动可用图表表示。距离-时间图中，匀速运动表现为不变的斜率；斜率越陡，速率越大。速度-时间图中，斜率为加速度，曲线下的面积表示位移。
For constant acceleration, three useful equations link u, v, a, t and s (displacement):
对于匀加速运动，三个有用的方程联系起 u、v、a、t 和 s（位移）：
v = u + at
s = ut + ½at²
v² = u² + 2as
3. Newton's Laws of Motion | 牛顿运动定律
Newton's First Law: An object remains at rest or moves with constant velocity unless acted on by an unbalanced force. This explains why a passenger lurches forward when a car brakes suddenly – inertia resists the change in motion.
牛顿第一定律：除非受到非平衡力作用，物体将保持静止或匀速直线运动状态。这解释了为什么汽车急刹车时乘客会前倾——惯性抵制运动状态的变化。
Newton' y proportional to the unbalanced force and inversely proportional to its mass: F = ma. A 2 kg mass pushed with 6 N accelerates at 3 m s⁻².
牛顿第二定律：物体的加速度与所受非平衡力成正比，与其质量成反比：F = ma。一个 2 kg 的物体受到 6 N 的力，产生的加速度为 3 m s⁻²。
Newton's Third Law: For every action force there is an equal and opposite reaction force. These forces act on different bodies. A rocket engine pushes exhaust gases downward; the gases push the rocket upward with an equal force.
牛顿第三定律：每一个作用力都有一个大小相等、方向相反的反作用力，且作用在不同物体上。火箭发动机将废气向下推出，废气给火箭施加一个大小相等、向上的推力。
4. Energy, Work and Power | 能量、功与功率
d in the direction of the force). Energy is the ability to do work; both are measured in joules (J).
当一个力使物体移动时就做了功：W = Fd（其中 d 为沿力方向移动的距离）。能量是做功的能力；两者的单位都是焦耳 (J)。
= ½mv². In a closed system, energy is conserved; it can be transformed but not destroyed.
增加的重力势能为 Eₚ = mgh（质量 × 重力场强 × 高度）。动能为 Eₖ = ½mv²。在一个封闭系统中，能量守恒；它可以转换形式但不会消失。
tt is one joule per second. Efficiency = (useful output energy ÷ total input energy) × 100%, and it is always less than 100% due to energy dissipation as heat.
功率是做功或转移能量的速率：P = E ÷ t。1 瓦特表示每秒 1 焦耳。效率 = (有用输出能量 ÷ 总输入能量) × 100%，由于能量会以热的形式散失，效率总是小于 100%。
5. Gas Laws and the Kinetic Model | 气体定律与分子动理论
A, measured in pascals (Pa). A gas exerts pressure because its particles collide with the walls of the container, and those collisions produce force.
压强是单位面积所受的力：p = F ÷ A，单位是帕斯卡 (Pa)。气体产生压强是由于其粒子不断撞击容器壁，这些碰撞产生了力。
fixed mass of gas at constant temperature, pressure and volume are inversely proportional – Boyle' he volume is halved, the pressure doubles because particles hit the walls more frequently.
对于一定质量的气体，在温度不变时，压强与体积成反比——玻意耳定律：p₁V₁ = p₂V₂。若体积减半，压强便加倍，因为粒子撞击器壁的频率增大。
Charle's Law and the Pressure Law link volume–temperature and pressure– gives the general gas equation: pV ÷ T = constant, provided T is in kelvin (K = °C + 273).
查理定律和压强定律分别给出体积-温度、压强-温度的关系。综合两者得到通用气体方程：pV ÷ T = 常数，前提是温度 T 使用开尔文 (K = °C + 273)。
The kinetic model explains these laws: temperature is a measure of the average kinetic energy of particles. Heating a gas makes the particles move faster, increasing both pressure (if volume is fixed) and volume (if pressure is fixed).
分子动理论解释了这些定律：温度是粒子平均动能的量度。加热气体会使粒子运动加快，若体积不变则压强增大，若压强不变则体积增大。
6. Electric Circuits and Ohm's Law | 电路与欧姆定律
nce (voltage) is the energy transferred per unit charge: V = E ÷ Q, measured in volts (V).
电流是电荷的流动：I = Q ÷ t，单位是安培 (A)。电势差（电压）是单位电荷转移的能量：V = E ÷ Q，单位是伏特 (V)。
Resistance opposes the current flow. Ohm' The resistance of a component is the ratio of voltage across it to the current through it.
电阻阻碍电流的流动。欧姆定律指出：对于温度不变的金属导体，V 与 I 成正比：V = IR。一个元件的电阻等于其两端的电压与通过电流之比。
rywhere, and the total resistance is the sum of individual resistances: Rₜₒₜₐₓ = R₁ + R₂ + … ch, and the total resistance decreases as more branches are added; 1/Rₜₒₜₐₓ = 1/R₁ + 1/R₂.
在串联电路中，各处电流相等，总电阻为各电阻之和：Rₜₒₜₐₓ = R₁ + R₂ + … 在并联电路中，各支路电压相同，增加支路会使总电阻减小；1/Rₜₒₜₐₓ = 1/R₁ + 1/R₂。
7. Electrical Power and Energy | 电功率与电能
Electrical power is the rate at which electrical energy is transferred: P = IV. Using Ohm's law, we can also write P = I²R and P = V² ÷ R. A 12 V lamp drawing 0.5 A has a power of 6 W.
电功率是电能转移的速率：P = IV。结合欧姆定律，还可以写成 P = I²R 和 P = V² ÷ R。一个 12 V 的灯泡通过 0.5 A 的电流，其功率为 6 W。
Energy transferred is power × time: E = Pt. Electricity meters record energy in kilowatt‑hours (kWh). For example, a 2 kW heater used for 3 hours consumes 6 kWh of energy.
转移的电能为功率 × 时间：E = Pt。电能表以千瓦时 (kWh) 记录能量。例如，一个 2 kW 的取暖器使用 3 小时消耗 6 kWh 的能量。
Fuses and circuit breakers protect circuits by melting or tripping when current exceeds a safe value. The fuse rating should be slightly above the normal operating current of the appliance.
保险丝和断路器在电流超过安全值时熔断或跳闸，以保护电路。保险丝的额定电流应略高于电器的正常工作电流。
8. Wave Properties | 波的特性
Waves transfer energy without transferring matter. Transverse waves (e.g. light, water waves) have oscillations perpendicular to the direction of energy travel; longitudinal waves (e.g. sound) have oscillations parallel to the direction.
波传递能量而不传递物质。横波（例如光波、水波）的振动方向与能量传播方向垂直；纵波（例如声波）的振动方向与传播方向平行。
e number of waves per second, measured in hertz (Hz); period (T) = 1/f. The wave speed is given by v = fλ.
关键术语：波长 (λ) 是相邻波峰间的距离；振幅是离开平衡位置的最大位移；频率 (f) 是每秒的波数，单位是赫兹 (Hz)；周期 (T) = 1/f。波速公式为 v = fλ。
All waves can undergo reflection, refraction and diffraction. Refraction occurs when a wave enters a new medium and changes speed, causing bending. Diffraction is the spreading of waves when they pass through a gap or around an obstacle, and is most pronounced when the gap size is comparable to the wavelength.
所有波都能发生反射、折射和衍射。折射发生在波进入新介质并改变速度时，引起偏折。衍射是波穿过狭缝或绕过障碍物时的扩展现象，当狭缝尺寸与波长相近时效果最明显。
9. Electromagnetic Spectrum and Refraction | 电磁波谱与折射
of decreasing wavelength: radio waves, microwaves, infrared, visible light, ultraviolet, X‑rays and gamma rays. All travel at 3 × 10⁸ m s⁻¹ in a vacuum.
电磁波谱按波长递减的顺序包括：无线电波、微波、红外线、可见光、紫外线、X 射线和伽马射线。它们在真空中的传播速度均为 3 × 10⁸ m s⁻¹。
Each type of radiation has different uses and hazards. Radio waves are used for communication; microwaves for cooking and radar; infrared for thermal imaging; ultraviolet for sterilisation but can cause skin cancer; X‑rays for medical imaging; gamma rays for cancer treatment and sterilisation but are highly ionising.
不同类型的电磁波有不同的用途和危害。无线电波用于通讯；微波用于烹饪和雷达；红外线用于热成像；紫外线用于消毒但可能导致皮肤癌；X 射线用于医学成像；伽马射线用于癌症治疗和灭菌，但具有强电离性。
When light passes from one medium to another, it changes speed and bends – e of incidence and r is the angle of refraction. If light enters a denser medium it bends towards the normal.
当光从一种介质进入另一种介质时，速度改变并发生弯曲——这就是折射。折射率 n = sin i / sin r，其中 i 为入射角，r 为折射角。若光进入光密介质，它会向法线靠拢。
Total internal reflection occurs when the angle of incidence inside a dense medium exceeds the critical angle, and all light is reflected. This principle is used in optical fibres for high‑speed data transmission.
当光密介质内的入射角大于临界角时，会发生全内反射，所有光都被反射。这一原理用于光纤实现高速数据传输。
10. Nuclear Radiation and Half-Life | 核辐射与半衰期
An atom consists of protons and neutrons in the nucleus, with electrons orbiting. Isotopes of an element have the same number of protons but different numbers of neutrons. Some isotopes are unstable and emit radiation to become more stable.
原子由原子核中的质子和中子及绕核运动的电子组成。同位素质子数相同但中子数不同。某些同位素不稳定，会通过辐射变得更加稳定。
There are three main types of nuclear radiation: alpha (α) particles – 42He nuclei, strongly ionising, stopped by paper; beta (β) particles – fast electrons 0−1e, moderately ionising, stopped by aluminium; gamma (γ) rays – electromagnetic waves, weakly ionising but highly penetrating, stopped by thick lead or concrete.
核辐射主要有三种：α 粒子——42He 核，电离能力强，能被纸挡住；β 粒子——高速电子 0−1e，电离能力中等，可被铝片阻挡；γ 射线——电磁波，电离能力弱但穿透力极强，需要厚铅板或混凝土阻挡。
Radioactive decay is random, but the half‑life is the time for half the nuclei in a sample to decay. After one half‑life the activity halves. The activity A is measured in becquerels (Bq); 1 Bq = 1 decay per second.
放射性衰变是随机的，但半衰期是样本中半数原子核发生衰变所需的时间。每经过一个半衰期，活度减半。活度 A 的单位是贝可勒尔 (Bq)；1 Bq = 每秒 1 次衰变。
N = N₀ (½)t / T½
Nuclear radiation has both uses and dangers. Alpha sources are used in smoke detectors; beta sources in thickness gauging; gamma sources in radiotherapy. However, ionising radiation can damage cells and DNA, so safe handling with shielding, distance and limited exposure time is essential.
核辐射既有用途也有危害。α 源用于烟雾探测器；β 源用于厚度测量；γ 源用于放射治疗。然而，电离辐射会损伤细胞和 DNA，因此必须通过屏蔽、保持距离和限制暴露时间来安全操作。
11. Space Physics: Gravity, Projectiles and Satellites | 空间物理：重力、抛体与卫星
itational force acting on a mass: W = mg, where g is the gravitational field strength (9.8 N on Earth). Mass is a scalar; weight is a vector directed towards the centre of the planet.
重量是作用在物体上的重力：W = mg，其中 g 是重力场强（地球表面约为 9.8 N kg⁻¹）。质量是标量；重量是指向地心的矢量。
izontal velocity remains constant, while the vertical motion is governed by the equations of uniform acceleration with a = −g.
抛体是只受重力和空气阻力（常被忽略）作用的物体。其水平运动和竖直运动相互独立。水平速度保持不变，竖直运动服从匀加速运动方程，加速度 a = −g。
le launched horizontally from a height, the time of flight depends only on the height: t = √2h ÷ g. The horizontal range is horizontal velocity × time of flight.
对于从某一高度水平抛出的物体，飞行时间仅取决于高度：t = √2h ÷ g。水平射程等于水平速度乘以飞行时间。 Published by TutorHao | Year 10 Physics Revision Series | aleveler.com
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