📚 Year 12 CCEA Science: Formula & Theorem Quick Reference Handbook | CCEA 12年级科学公式定理速查手册
This handbook collects the essential formulas, equations and key theorems you need for CCEA Year 12 Science. It covers physics, chemistry and biology calculations that regularly appear in GCSE Double Award and separate Science papers. Use it as a rapid revision aid to check symbols, units and relationships before your exams.
本手册汇集了CCEA 12年级科学考试必备的核心公式、方程与关键定理，涵盖物理、化学和生物中常见的计算题。你可以把它当作考前快速回顾的速查工具，随时核对符号、单位与公式关系。
1. Physics: Motion and Forces | 物理：运动与力
Average speed is the total distance travelled divided by the total time taken. The standard unit is metres per second (m/s).
平均速度等于总移动距离除以总时间，标准单位为米每秒 (m/s)。
v = d ÷ t
Acceleration is the rate of change of velocity. It is calculated as the change in velocity divided by the time taken for that change.
加速度是速度变化的快慢，等于速度变化量除以发生该变化所用的时间。
a = (v - u) ÷ t
For uniform acceleration you can also find the distance travelled using the average velocity. The equation works when acceleration is constant.
对于匀加速运动，你也可以用平均速度求出位移，该方程仅适用于加速度恒定的情况。
s = (u + v) ÷ 2 × t
Newton's second law states that the resultant force acting on an object is equal to its mass multiplied by its acceleration. Force is measured in newtons (N).
牛顿第二定律指出，作用在物体上的合力等于物体的质量乘以加速度。力的单位是牛顿 (N)。
F = m × a
Weight is the gravitational force on an object. It depends on mass and the gravitational field strength g, which is about 10 N/kg on Earth.
重量是作用在物体上的重力，大小取决于质量与引力场强度 g (地球上约为 10 N/kg)。
W = m × g
Momentum is the product of mass and velocity. It is a vector quantity and in a closed system the total momentum before and after a collision is conserved.
动量是质量与速度的乘积，是矢量。在封闭系统中，碰撞前后的总动量守恒。
p = m × v
For a lever or turning effect, moment of a force is the force multiplied by the perpendicular distance from the pivot. The unit is newton-metre (Nm).
杠杆或转动效应中，力矩等于力乘以到支点的垂直距离，单位为牛顿·米 (Nm)。
M = F × d
2. Physics: Energy and Power | 物理：能量与功率
Kinetic energy is the energy an object has due to its motion. It depends on mass and the square of its speed.
动能是物体由于运动而具有的能量，取决于质量和速度的平方。
Ek = ½ m v²
Gravitational potential energy is stored energy due to an object's position in a gravitational field. It increases with height, mass and g.
重力势能是物体在引力场中因位置而储存的能量，随高度、质量和 g 增大而增加。
Ep = m g h
Work done is energy transferred when a force moves an object. It is equal to the force multiplied by the distance moved in the direction of the force.
功是力使物体移动时转移的能量，等于力乘以物体在力的方向上移动的距离。
W = F d
Power is the rate at which work is done or energy is transferred. The unit is the watt (W), equivalent to one joule per second.
功率是做功或能量转换的速率，单位为瓦特 (W)，相当于每秒一焦耳。
P = E ÷ t
Efficiency compares useful output energy to total input energy. It can be expressed as a decimal or as a percentage.
效率对比有用输出能量与总输入能量，可以用小数或百分比表示。
Efficiency = (useful output energy ÷ total input energy) × 100%
3. Physics: Electricity | 物理：电学
Electric charge transferred in a circuit is the product of current and time. It is measured in coulombs (C).
电路中转移的电荷量等于电流与时间的乘积，单位为库仑 (C)。
Q = I t
Potential difference (voltage) is the energy transferred per unit charge. It is measured in volts (V).
电势差(电压)是单位电荷转移的能量，单位为伏特 (V)。
V = W ÷ Q
Resistance is the ratio of potential difference to current. Ohm's law states that for an ohmic conductor at constant temperature, V is proportional to I.
电阻是电势差与电流的比值。欧姆定律指出，在温度不变时，欧姆导体的 V 与 I 成正比。
R = V ÷ I
For resistors connected in series, the total resistance is the sum of the individual resistances.
电阻串联时，总电阻等于各电阻之和。
Rtotal = R1 + R2 + ...
For resistors in parallel, the reciprocal of the total resistance equals the sum of the reciprocals of individual resistances.
电阻并联时，总电阻的倒数等于各电阻倒数之和。
1 ÷ Rtotal = 1 ÷ R1 + 1 ÷ R2 ...
Electrical power can be calculated in several ways using current, voltage and resistance. The unit of power is the watt (W).
电功率可以通过电流、电压和电阻以多种方式计算，单位为瓦特 (W)。
P = I V = I² R = V² ÷ R
Energy transferred by an electric current depends on power and time. It is commonly measured in joules (J) or kilowatt-hours (kWh).
电流传递的能量取决于功率和时间，常用焦耳 (J) 或千瓦时 (kWh) 表示。
E = P t = I V t
4. Physics: Waves and Optics | 物理：波与光学
Wave speed is the product of frequency and wavelength. This relationship applies to all waves, including light, sound and water waves.
波速等于频率与波长的乘积，适用于包括光波、声波和水波在内的所有波。
v = f λ
The period of a wave is the time for one complete oscillation and is the reciprocal of frequency.
波的周期是完成一次完整振动所需的时间，是频率的倒数。
T = 1 ÷ f
When light passes from one medium to another, Snell's law relates the angles of incidence and refraction to the refractive index n of the material.
当光从一种介质进入另一种介质时，斯涅尔定律将入射角和折射角与材料的折射率 n 联系起来。
n = sin i ÷ sin r
The critical angle c and refractive index n are linked. Total internal reflection occurs when the angle of incidence exceeds the critical angle.
临界角 c 与折射率 n 相关。当入射角大于临界角时发生全内反射。
sin c = 1 ÷ n
5. Chemistry: Quantitative Chemistry | 化学：定量化学
easured in moles (mol). One mole of any substance contains 6.02 × 10²³ particles (Avogadro's number).
物质的量以摩尔(mol)计量。1摩尔任何物质含有6.02 × 10²³个粒子(阿伏伽德罗常数)。
n = m ÷ M
Relative atomic mass Ar is the weighted average mass of an element's isotopes relative to 1/12 of the mass of carbon-12. It has no units.
相对原子质量 Ar 是元素同位素质量相对于碳-12质量的1/12的加权平均值，没有单位。
Relative formula mass Mr is the sum of the relative atomic masses of the atoms in a formula unit.
相对分子质量 Mr 是化学式中各原子相对原子质量的总和。
Concentration of a solution expressed in mol/dm³ can be found from the amount of solute and the volume of solution.
以 mol/dm³ 表示的溶液浓度可由溶质的物质的量和溶液体积求出。
c = n ÷ V
At room temperature and pressure (rtp), one mole of any gas occupies a volume of 24 dm³ or 24 000 cm³.
在室温和常压 (rtp) 下，1摩尔任何气体的体积为24 dm³ 或 24 000 cm³。
Vgas = n × 24
Percentage yield compares the mass of product actually obtained with the maximum theoretical mass. Atom economy measures efficiency of a reaction in terms of reactant atoms incorporated into the desired product.
产率比较实际获得的产品质量与理论最大质量。原子经济性衡量反应物中有多少原子进入了期望产物。
% Yield = (actual mass ÷ theoretical mass) × 100%
Atom economy = (Mr of desired product ÷ sum of Mr of all reactants) × 100%
6. Chemistry: Energy Changes, Rates & Equilibrium | 化学：能量变化、速率与平衡
solution, its specific heat capacity (c = 4.2 J/g°C for water) and the temperature change.
溶液反应中的热量变化可通过溶液质量、比热容 (水为 c = 4.2 J/g°C) 和温度变化计算。
q = m c ΔT
Molar enthalpy change ΔH relates the heat energy to the number of moles reacting. It is expressed in kJ/mol and the sign is negative for exothermic reactions.
摩尔焓变 ΔH 将热量与反应的摩尔数相联系，单位为 kJ/mol，放热反应为负值。
ΔH = -q ÷ n
The average rate of a reaction can be determined by measuring the quantity of reactant used or product formed over time.
反应的平均速率通过测量单位时间内反应物的消耗量或生成物的生成量来确定。
Average rate = quantity change ÷ time taken
Le Chatelier's principle states that if a system at equilibrium is subjected to a change in concentration, temperature or pressure, the equilibrium position shifts to oppose the change.
勒夏特列原理指出，如果改变一个处于平衡状态的系统的浓度、温度或压强，平衡将向减弱这种改变的方向移动。
7. Biology: Microscopy and Magnification | 生物学：显微镜与放大率
Total magnification of a light microscope is the product of the eyepiece lens magnification and the objective lens magnification.
光学显微镜的总放大倍率是目镜放大倍率与物镜放大倍率的乘积。
Total magnification = eyepiece magnification × objective magnification
The magnification equation links the size of an image or drawing to the actual size of the specimen. Remember to use the same units for both sizes.
放大率公式将图像或绘图的大小与标本的实际尺寸联系起来，需确保两者使用相同的单位。
Magnification = image size ÷ actual size
When converting between units, 1 cm = 10 mm, 1 mm = 1000 µm and 1 µm = 1000 nm. Always check the unit required in the question.
进行单位换算时，1 cm = 10 mm，1 mm = 1000 µm，1 µm = 1000 nm。一定要看清题目要求的单位。
8. Biology: Physiological and Ecological Calculations | 生物学：生理与生态计算
Cardiac output is the volume of blood pumped by the heart per minute. It is the product of heart rate and stroke volume.
心输出量是心脏每分钟泵出的血液量，等于心率与每搏输出量的乘积。
Cardiac output = heart rate × stroke volume
The respiratory quotient (RQ) indicates the type of substrate being respired. It is the ratio of carbon dioxide produced to oxygen consumed.
呼吸商 (RQ) 反映正在被呼吸的底物类型，它是生成的二氧化碳量与消耗的氧气量之比。
RQ = CO₂ produced ÷ O₂ used
The Lincoln index estimates population size using a capture-mark-recapture method. It assumes a closed population and thorough mixing.
林肯指数使用标记重捕法估算种群大小，假设种群封闭且个体充分混合。
N = (M × C) ÷ R
Efficiency of energy transfer between trophic levels compares the energy available to the next level with the energy consumed at the present level.
营养级之间的能量传递效率对比下一级可获得的能量与本级摄入的能量。
Efficiency = (energy available to next level ÷ energy ingested) × 100%
9. Biology: Genetic Ratios and Probability | 生物学：遗传比率与概率
o heterozygous individuals (Tt × Tt) gives a 3:1 phenotype ratio of dominant to recessive. Published by TutorHao | Year 12 Science Revision Series | aleveler.com
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