PART I · PAPER 1 STYLE第一部分 · 第一卷风格Short structured · calculator · 30 marks短结构题 · 可用计算器 · 30 分
Short Structured Items短结构题
Show all working in the space below each question. Marks are awarded for correct method as well as final answers. State definitions precisely; the examiner rewards "transfers energy, not matter" and a clear classification of wave type. Give numerical answers to an appropriate number of significant figures.在每题下方空白处写出全部解题过程。方法分（method marks）与最终答案同等重要。精确陈述定义；阅卷给"传递能量而非物质"以及对波类型的清晰分类以分。数值答案保留适当的有效数字。
A cork floats on a pond. A travelling water wave of amplitude $4.0\ \mathrm{cm}$ passes the cork, which bobs up and down many times as the wave goes by.一软木塞浮在池塘上。一列振幅 $4.0\ \mathrm{cm}$ 的行波经过软木塞，波经过时软木塞多次上下起伏。
(a)State the net horizontal displacement of the cork after many waves have passed, and state what physical quantity the wave transports across the pond.写出许多波经过后软木塞的净水平位移，并写出波横跨池塘所传输的物理量。[2]
(b)The wave is replaced by one of the same frequency but twice the amplitude. State, with reasoning, the factor by which the power transported by the wave changes.将该波换成频率相同但振幅为两倍的波。写出波所传输功率的变化倍数，并说明理由。[2]
Q2MEDIUMPaper 1transverse vs longitudinal, polarisation横波与纵波、偏振[6 marks]
A loudspeaker cone vibrates back and forth along the straight line that points toward a listener, producing a sound wave in air.扬声器纸盆沿指向听者的直线来回振动，在空气中产生一列声波。
(a)Classify the sound wave as transverse or longitudinal, justifying your choice by comparing the direction of particle oscillation with the direction of energy transfer.将该声波分类为横波或纵波，并通过比较质点振动方向与能量传递方向来论证你的选择。[2]
(b)Describe what happens to the air molecules at a compression and at a rarefaction.描述压缩处与稀疏处的空气分子各自发生了什么。[2]
(c)A second wave can be polarised. State whether this wave is transverse or longitudinal, and explain why this single observation is enough to decide.另一列波可以被偏振。写出该波是横波还是纵波，并解释为何仅凭这一观察即可判定。[2]
A sound wave in air has frequency $512\ \mathrm{Hz}$ and travels at $340\ \mathrm{m\,s^{-1}}$.空气中一列声波频率为 $512\ \mathrm{Hz}$，传播速度 $340\ \mathrm{m\,s^{-1}}$。
(a)Calculate the wavelength of the sound.计算该声波的波长。[2]
(b)Calculate the period of the sound.计算该声波的周期。[2]
(c)The same sound passes from the air into water, where it travels faster. State what happens to its frequency and to its wavelength, justifying each answer with the wave equation.同一声波由空气进入水中，速度变快。写出其频率与波长如何变化，并各用波动方程加以论证。[2]
Q4HARDPaper 1wavefronts and rays波前与射线[6 marks]
A ripple-tank diagram shows circular wavefronts spreading from a point source (a dipper) that vibrates at $8.0\ \mathrm{Hz}$. Two adjacent crest wavefronts are $2.5\ \mathrm{cm}$ apart.水波槽示意图显示由以 $8.0\ \mathrm{Hz}$ 振动的点波源（振子）扩散出的圆形波前。相邻两个波峰波前相距 $2.5\ \mathrm{cm}$。
(a)State the wavelength of the wave, explaining how the wavefront spacing gives it.写出该波的波长，并解释波前间距如何给出它。[1]
(b)Calculate the speed of the wave.计算该波的波速。[2]
(c)State the angle between a ray and the wavefront it crosses, and state what a ray represents.写出射线与其穿过的波前之间的夹角，并说明射线表示什么。[1]
(d)Describe how the shape of the wavefronts and the rays change far from the source compared with close to the source.描述远离波源处的波前形状与射线相对靠近波源处如何变化。[2]
The electromagnetic spectrum runs from radio waves to gamma rays.电磁波谱从无线电波延伸到伽马射线。
(a)List the seven principal bands of the electromagnetic spectrum in order of increasing frequency.按频率递增的顺序列出电磁波谱的七个主要波段。[2]
(b)Red light has wavelength $6.5\times10^{-7}\ \mathrm{m}$ in vacuum. Calculate its frequency.红光在真空中的波长为 $6.5\times10^{-7}\ \mathrm{m}$。计算其频率。[3]
(c)State how the vacuum speed of an X-ray compares with that of the red light, and state two further properties shared by all electromagnetic waves.写出真空中 X 射线的速度与红光的比较，并写出所有电磁波共有的另外两条性质。[3]
PART II · PAPER 1B / DATA ANALYSIS第二部分 · 第一卷 B / 数据分析Graphs · data · uncertainties · 22 marks图像 · 数据 · 不确定度 · 22 分
Graph and Data Questions图像与数据题
These items reward careful reading of the horizontal-axis label, the correct extraction of $\lambda$ and $T$, and proper handling of uncertainties. Quote uncertainties to one significant figure and round the value to match.这些题考查对横轴标签的细致辨认、对 $\lambda$ 与 $T$ 的正确读取，以及对不确定度的正确处理。不确定度保留 1 位有效数字，并使数值的末位与之对齐。
Q6HARDPaper 1Bdisplacement-distance vs displacement-time graphs位移-距离图与位移-时间图[12 marks]
A single travelling wave is studied with two graphs. Graph 1 is a displacement-distance graph (a snapshot of the whole wave at one instant); Graph 2 is a displacement-time graph for one particle of the medium. The repeat features read off the graphs are tabulated below; both graphs have a peak displacement of $3.0\ \mathrm{cm}$.用两种图研究同一列行波。图 1 是位移-距离图（某一瞬时整列波的快照）；图 2 是介质中某一质点的位移-时间图。从图中读出的重复特征列于下表；两图的峰值位移均为 $3.0\ \mathrm{cm}$。
Graph图
Horizontal axis横轴
One full repeat一个完整重复
1
distance $x\ /\ \mathrm{m}$距离 $x\ /\ \mathrm{m}$
$0.80$
2
time $t\ /\ \mathrm{s}$时间 $t\ /\ \mathrm{s}$
$0.025$
(a)State which graph the wavelength is read from and which graph the period is read from, in each case naming the axis quantity that tells you.写出波长从哪张图读取、周期从哪张图读取，每种情形指出据以判断的横轴量。[2]
(b)State the amplitude and the wavelength of the wave.写出该波的振幅与波长。[2]
(c)Determine the frequency of the wave.求该波的频率。[2]
(d)Calculate the speed of the wave.计算该波的波速。[2]
(e)The wave travels in the direction of increasing $x$. On Graph 1 a particle sits on the leading edge of a crest. State whether that particle is next moving up or down, with reasoning.该波沿 $x$ 增大方向传播。在图 1 中某质点位于一波峰的前缘。写出该质点下一刻是向上还是向下运动，并说明理由。[2]
(f)A student reads the value $0.80$ off Graph 1 and records it as the period. Explain the error and state the correct quantity that $0.80$ represents.一名学生从图 1 读出 $0.80$ 并将其记为周期。解释该错误，并写出 $0.80$ 实际代表的正确物理量。[2]
Q7HARDPaper 1Bripple-tank data + uncertainty水波槽数据与不确定度[10 marks]
In a ripple tank a student measures, with a ruler held across a still photograph, the distance spanned by $5$ complete wavelengths as $(12.0 \pm 0.2)\ \mathrm{cm}$. A timer records that the dipper completes $20$ full oscillations in $8.0\ \mathrm{s}$.在水波槽中，学生用尺在静止照片上量得 $5$ 个完整波长所跨的距离为 $(12.0 \pm 0.2)\ \mathrm{cm}$。计时器记录振子在 $8.0\ \mathrm{s}$ 内完成 $20$ 次完整振动。
(a)Calculate the wavelength of the ripples, explaining why dividing by $5$ improves the result.计算波纹的波长，并解释为何除以 $5$ 能改善结果。[3]
(b)Determine the period and hence the frequency of the dipper.求振子的周期，并由此求其频率。[2]
(c)Calculate the speed of the ripples.计算波纹的波速。[2]
(d)The measured span has an absolute uncertainty of $\pm 0.2\ \mathrm{cm}$. Calculate the percentage uncertainty in the measured span (and hence in the wavelength).所测跨距的绝对不确定度为 $\pm 0.2\ \mathrm{cm}$。计算所测跨距（从而波长）的百分比不确定度。[3]
PART III · PAPER 2 STYLE第三部分 · 第二卷风格Extended structured · calculator · 28 marks长结构题 · 可用计算器 · 28 分
Extended Structured Problems长结构问题
Set up each problem with clear definitions and a diagram where useful. Method marks dominate the longer items; carry intermediate values to extra figures and round only the final answer.每题先写清定义，必要时画示意图。长题中方法分占比最大；中间值多保留几位，仅在最终答案处取舍有效数字。
Sound in air is a mechanical longitudinal wave that travels at approximately $340\ \mathrm{m\,s^{-1}}$. Light travels at $c = 3.00\times10^{8}\ \mathrm{m\,s^{-1}}$.空气中的声音是一种机械纵波，传播速度约为 $340\ \mathrm{m\,s^{-1}}$。光以 $c = 3.00\times10^{8}\ \mathrm{m\,s^{-1}}$ 传播。
(a)State two properties of a sound wave in air that follow from it being a mechanical longitudinal wave.写出空气中声波因其为机械纵波而具有的两条性质。[2]
(b)A tuning fork emits a note of frequency $256\ \mathrm{Hz}$. Calculate the wavelength of this sound in air.一支音叉发出频率 $256\ \mathrm{Hz}$ 的音。计算该声波在空气中的波长。[3]
(c)During a storm an observer sees a lightning flash and hears the thunder $6.0\ \mathrm{s}$ later. Estimate the distance to the strike, stating clearly the assumption you make about the travel time of the light.暴风雨中观察者看到闪电，$6.0\ \mathrm{s}$ 后听到雷声。估算到雷击处的距离，并清楚写出你对光传播时间所作的假设。[3]
(d)A person claps once facing a cliff and hears a single echo $1.5\ \mathrm{s}$ later. Calculate the distance from the person to the cliff.一人面向峭壁拍一次手，$1.5\ \mathrm{s}$ 后听到一次回声。计算此人到峭壁的距离。[3]
(e)Explain, in terms of wave type and the need for a medium, why the lightning is seen almost instantly while the thunder is heard much later.从波的类型与是否需要介质的角度，解释为何闪电几乎瞬间被看到而雷声晚得多才被听到。[3]
All electromagnetic waves travel at $c = 3.00\times10^{8}\ \mathrm{m\,s^{-1}}$ in vacuum and obey $c = f\lambda$.所有电磁波在真空中以 $c = 3.00\times10^{8}\ \mathrm{m\,s^{-1}}$ 传播，并遵循 $c = f\lambda$。
(a)A microwave used in a radar has a wavelength of $0.12\ \mathrm{m}$ in vacuum. Calculate its frequency.雷达所用微波在真空中的波长为 $0.12\ \mathrm{m}$。计算其频率。[3]
(b)This microwave then enters a dielectric block in which its speed falls to $2.00\times10^{8}\ \mathrm{m\,s^{-1}}$. Determine its wavelength in the block, justifying which quantity stays fixed.该微波随后进入一介质块，其速度降为 $2.00\times10^{8}\ \mathrm{m\,s^{-1}}$。求其在介质块中的波长，并论证哪个量保持不变。[3]
(c)An FM radio station broadcasts at $98\ \mathrm{MHz}$. Calculate the wavelength of the radio wave in vacuum, and state which band of the spectrum it belongs to.一座 FM 电台以 $98\ \mathrm{MHz}$ 广播。计算该无线电波在真空中的波长，并写出它属于波谱的哪个波段。[3]
(d)State whether the radar microwave and the FM radio wave have the same speed in vacuum, and give two further properties they share as electromagnetic waves.写出雷达微波与 FM 无线电波在真空中速度是否相同，并给出它们作为电磁波共有的另外两条性质。[3]
(e)Explain why sound is not part of the electromagnetic spectrum.解释为何声音不属于电磁波谱。[2]