📚 Year 7 WJEC Physics Unit Test Mock Paper: Detailed Solutions | WJEC 七年级物理单元测试模拟卷解析
This article provides a complete walkthrough of a mock unit test for Year 7 WJEC Physics, covering fundamental topics such as forces, energy, electricity, matter, waves and space. Each question is followed by a detailed solution and tips to help you understand common pitfalls and improve your exam technique.
本文提供了一份针对WJEC七年级物理单元测试模拟卷的全面解析，涵盖力、能量、电、物质、波和太空等基础主题。每个题目附有详细解答和技巧提示，帮助你理解常见错误并提升应试能力。
1. Question 1: Forces and Their Effects | 第1题：力及其效应
Question: Name three contact forces and give one real-life example for each. (3 marks)
题目：列举三种接触力，并各举一个生活中的例子。（3分）
A contact force acts only when two objects physically touch. Three common examples are friction, tension and normal reaction.
接触力仅在两个物体实际接触时产生作用。三种常见的例子是摩擦力、张力和支持力。
Friction occurs when surfaces rub against each other, such as the grip of car tyres on the road. Tension is the pulling force transmitted through a string, cable or rope – for instance, the force in a leash when walking a dog. Normal reaction is the upwards push from a surface that supports an object, like a book resting on a table.
摩擦力在表面相互摩擦时产生，例如汽车轮胎在路面上的抓地力。张力是通过线、缆或绳传递的拉力——比如遛狗时牵绳上的力。支持力是支撑物体的表面对它向上的推力，像放在桌上的书。
In an exam, always state the type of force and link it directly to a specific situation. Avoid vague descriptions such as ‘push’ or ‘pull’ without naming the force.
考试时，一定要说明力的类型并直接联系具体情境。避免模糊的描述如“推”或“拉”而不指出力名称。
2. Question 2: Speed Calculation | 第2题：速度计算
Question: A cyclist travels 150 metres in 30 seconds. Calculate the average speed of the cyclist. Include the formula and unit. (2 marks)
题目：一名自行车手在30秒内行驶了150米。计算其平均速度。写出公式和单位。（2分）
The relationship linking speed, distance and time is:
速度、距离和时间的关系为：
speed = distance ÷ time
速度 = 距离 ÷ 时间
Substitute the given values: distance = 150 m, time = 30 s.
代入已知数值：距离 = 150 m，时间 = 30 s。
speed = 150 m ÷ 30 s = 5 m/s
速度 = 150 m ÷ 30 s = 5 m/s
Always write the unit m/s (metres per second). Many students lose marks by forgetting to include a unit or using incorrect units like m s⁻².
始终要写明单位 m/s（米每秒）。许多学生因遗漏单位或误用 m s⁻² 等单位而失分。
3. Question 3: Series Circuits and Current | 第3题：串联电路与电流
Question: A series circuit contains a 6 V battery and two identical lamps. State the voltage across each lamp. Explain what happens if one lamp is removed. (4 marks)
题目：一个串联电路包含一节6 V电池和两个相同灯泡。说明每个灯泡两端的电压。若其中一个灯泡被取下，解释会有什么现象。（4分）
lamps are identical, each lamp receives half of the total voltage: 6 V ÷ 2 = 3 V per lamp.
串联电路中，电源电压被各元件分担。由于灯泡相同，每个灯泡分得总电压的一半：6 V ÷ 2 = 3 V。
If one lamp is removed, the circuit is broken. Electric current cannot flow through an incomplete loop, so both lamps go out. This is because a series circuit provides only one path for current.
如果取下一个灯泡，电路就会断开。闭合回路不完整，电流无法通过，因此两个灯泡都会熄灭。这是因为串联电路只为电流提供一条路径。
For full marks, use the term ‘open circuit’ and mention that current stops everywhere in the loop at the same instant.
获得满分的要点是使用术语“断路”，并指出回路中各处电流同时停止。
4. Question 4: Energy Stores and Transfers | 第4题：能量储存与转移
Question: Describe the energy changes that take place when a ball is thrown vertically upwards until it reaches its highest point. (3 marks)
题目：描述一个球被竖直向上抛出直到最高点过程中发生的能量变化。（3分）
At the moment the ball leaves the hand, it has kinetic energy due to its motion. As it rises, kinetic energy is transferred to gravitational potential energy because the ball gains height.
球离开手的瞬间，因运动而具有动能。在上升过程中，动能转变为重力势能，因为球的高度增加。
At the highest point, the ball momentarily stops, so kinetic energy is zero, and all the initial kinetic energy has become gravitational potential energy (assuming no air resistance). Some energy is also transferred to the thermal energy store of the surroundings due to air resistance.
在最高点，球瞬间静止，动能为零，所有初始动能都转化为重力势能（忽略空气阻力）。由于空气阻力，一部分能量也会转移到周围环境的热能储存。
ways name the start and end energy stores clearly, e.g. kinetic → gravitational potential.
描述能量转移时，始终清晰说出起始和最终能量储存，例如动能 → 重力势能。
5. Question 5: Particle Model of Matter | 第5题：物质的粒子模型
Question: Draw particle diagrams for a solid and a gas. Use your diagrams to explain why solids have a fixed shape but gases expand to fill their container. (6 marks)
题目：画出固体和气体的粒子示意图。利用图示解释为什么固体有固定形状，而气体会膨胀充满容器。（6分）
In a solid, particles are arranged in a regular, closely packed pattern. They vibrate about fixed positions but cannot move past each other. Strong forces hold them together.
在固体中，粒子排列成规则、紧密堆积的模式。它们在固定位置附近振动，但不能自由移动越过彼此。强大的作用力将它们束缚在一起。
In a gas, particles are far apart and move randomly at high speeds in all directions. The forces between particles are negligible. This allows a gas to spread out and fill any available space.
在气体中，粒子相距很远，且以高速向各个方向随机运动。粒子间的作用力可忽略不计。这使得气体能够扩散并充满任何可用空间。
Consequently, a solid keeps its own shape because particles are locked in place, whereas a gas takes the shape and volume of its container because particles are free to move and separate.
因此，固体能保持自身形状是因为粒子被锁定在固定位置；而气体则随容器形状和体积变化，因为粒子可以自由移动和分离。
6. Question 6: Light and Reflection | 第6题：光与反射
Question: A ray of light strikes a plane mirror. Draw and label a ray diagram showing the incident ray, reflected ray, normal, angle of incidence and angle of reflection. State the law of reflection. (4 marks)
题目：一束光线照射到平面镜上。画出并标注光路图，标出入射光线、反射光线、法线、入射角和反射角。写出反射定律。（4分）
The law of reflection states that the angle of incidence equals the angle of reflection, and both angles are measured from the normal.
反射定律指出，入射角等于反射角，且两个角都是从法线开始测量。
In a correct diagram, the normal is a dashed line drawn perpendicular to the mirror surface at the point of incidence. The incident ray and reflected ray are drawn with arrows indicating direction. The angle of incidence (i) and angle of reflection (r) are clearly labelled and shown to be equal.
在正确的图示中，法线用虚线表示，画在入射点处与镜面垂直。入射光线和反射光线均用带箭头的线段表示方向。入射角（i）和反射角（r）要清晰标出并显示相等。
Common errors include drawing the normal at a slant or measuring angles from the mirror surface instead of the normal. Always measure from the normal to the ray.
常见错误包括将法线画偏斜，或从镜面而非从法线测量角度。务必从法线到光线进行测量。
7. Question 7: Sound and Hearing | 第7题：声音与听觉
Question: Explain why astronauts cannot hear each other directly in space, but can communicate using radio equipment. (2 marks)
题目：解释为什么宇航员在太空中不能直接听到对方说话，但能用无线电设备交流。（2分）
Sound is a mechanical wave that requires a medium (solid, liquid or gas) to travel. Space is a vacuum with almost no particles, so sound waves cannot propagate.
声音是一种机械波，需要介质（固体、液体或气体）才能传播。太空几乎是真空，粒子极少，因此声波无法传播。
Radio waves are electromagnetic waves and can travel through a vacuum. They do not need a medium, so astronauts can use radio devices to convert speech into radio signals and back to sound inside their suits.
无线电波是电磁波，能在真空中传播。它们不需要介质，因此宇航员可以用无线电设备将语音转换为无线电信号，并在宇航服内重新转换为声音。
To score full marks, distinguish clearly between mechanical waves (need medium) and electromagnetic waves (can travel in vacuum).
想获得满分，需清晰区分机械波（需要介质）和电磁波（可在真空中传播）。
8. Question 8: The Solar System | 第8题：太阳系
Question: List the planets in order from the Sun. State two reasons why Earth is able to support life. (3 marks)
题目：按距离太阳由近及远的顺序列出各大行星。说明地球能够维持生命的两个原因。（3分）
The order of the planets from the Sun is: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
各大行星距太阳由近到远的顺序是：水星、金星、地球、火星、木星、土星、天王星、海王星。
Earth can support life because it has liquid water on its surface and is at the right distance from the Sun to maintain a suitable temperature range. It also has an atmosphere that provides oxygen and protects from harmful radiation.
地球能维持生命是因为其表面存在液态水，并且与太阳的距离适中，能维持合适的温度范围。此外，它还有大气层，能提供氧气并阻挡有害辐射。
Acceptable answers also include the presence of a magnetic field or a protective ozone layer. Always give specific scientific reasons, not just 'it has air'.
可接受的答案还包括存在磁场或臭氧层保护。始终给出具体的科学原因，而不只是“有空气”。
9. Question 9: Practical Investigation – Hooke’s Law | 第9题：实验探究——胡克定律
Question: A student adds masses to a spring and measures its extension. They plot a graph of extension (cm) against force (N). Describe the expected shape of the graph. State the relationship between force and extension within the elastic limit. (5 marks)
题目：某学生向弹簧添加砝码并测量其伸长量，然后绘制伸长量（cm）与拉力（N）的关系图。描述预期的图线形状。说明在弹性限度内，拉力与伸长量的关系。（5分）
The graph is expected to show a straight line passing through the origin until the elastic limit is reached. This indicates that extension is directly proportional to the applied force.
预期图线将是一条经过原点的直线，直到达到弹性极限。这表明伸长量与所施加的拉力成正比。
Within the elastic limit, the relationship is:
在弹性限度内，关系式为：
force ∝ extension or F = k × x, where k is the spring constant.
拉力 ∝ 伸长量 或 F = k × x，其中 k 是弹簧常数。
Beyond the elastic limit, the spring deforms plastically and does not return to its original length; the graph curves. In the exam, label axes correctly and include units – extension (cm), force (N).
超过弹性极限后，弹簧发生塑性形变，无法恢复原长；图线发生弯曲。考试中，要正确标示坐标轴并注明单位——伸长量（cm），拉力（N）。
10. Question 10: Energy Resources | 第10题：能源
Question: Name two renewable and two non-renewable energy resources. Give one advantage of using renewable resources to generate electricity. (4 marks)
题目：列举两种可再生能源和两种不可再生能源。给出使用可再生能源发电的一个优点。（4分）
Renewable resources: solar power, wind power, tidal power, hydroelectric power (accept any two). Non-renewable resources: coal, oil, natural gas, nuclear fuel (accept any two).
可再生能源：太阳能、风能、潮汐能、水力发电（任选两种）。不可再生能源：煤、石油、天然气、核燃料（任选两种）。
A key advantage of renewable resources is that they will not run out, whereas fossil fuels are finite. Also, they generally produce no carbon dioxide during operation, which helps reduce climate change.
可再生能源的一个关键优点是它们不会枯竭，而化石燃料是有限的。此外，它们在运行中通常不产生二氧化碳，有助于减缓气候变化。
Ensure the advantage is clearly linked to the resource. For full marks, do not just say ‘they are better’ – give a scientific reason such as ‘no greenhouse gas emissions during generation’.
确保优点与资源明确关联。为获满分，不能只说“它们更好”——要给出科学理由，如“发电过程中不排放温室气体”。
11. Common Mistakes and How to Avoid Them | 第11节：常见错误及避免方法
ng numbers. Always show the equation first, e.g. speed = distance ÷ time, then substitute.
许多学生因未先写公式就直接代入数字而失分。务必先写出公式，如速度 = 距离 ÷ 时间，然后再代入。
Another typical error is confusing mass and weight. Weight is a force measured in newtons (N) and depends on gravity; mass is measured in kilograms (kg) and stays the same everywhere. Use weight = mass × gravitational field strength (W = m × g) where needed.
另一个典型错误是混淆质量和重量。重量是一种力，单位是牛顿（N），取决于重力；质量以千克（kg）为单位，在任何地方都保持不变。在需要时使用重量 = 质量 × 重力场强度（W = m × g）。
In circuit questions, do not assume that current is ‘used up’. Current is conserved in a series circuit; it is the same at all points. Energy is transferred, not current.
在电路题中，不要假设电流被“用掉”了。在串联电路中电流是守恒的；各点的电流大小相同。被转移的是能量，而不是电流。
When drawing diagrams, use a ruler and sharp pencil. Label all parts neatly. In particle diagrams, remember to leave space between particles for a gas and show random motion arrows.
画图时，使用直尺和削尖的铅笔。把各部分标示整洁。在粒子示意图中，记住气体粒子之间要留出空隙，并用箭头表示随机运动。
12. Mock Test Summary and Further Revision | 第12节：模拟测试总结与后续复习
This mock paper covered core Year 7 physics concepts: forces, motion, electricity, energy, matter, waves and space. Review any mistakes carefully and redo the questions without notes to test your understanding.
这份模拟卷涵盖了七年级物理的核心概念：力、运动、电、能量、物质、波和太空。仔细回顾任何错误，并在不借助笔记的情况下重做题目以检验理解。
Create flashcards for key definitions such as ‘contact force’, ‘kinetic energy’, ‘potential difference’ and ‘Hooke’s Law’. Practise drawing ray diagrams and circuit symbols until you can reproduce them accurately and quickly.
为关键定义制作记忆卡片，如“接触力”、“动能”、“电位差”和“胡克定律”。反复练习绘制光路图和电路符号，直到能够准确且快速地再现。
Finally, use past-paper questions from the WJEC website to familiarise yourself with the command words: ‘state’, ‘describe’, ‘explain’ and ‘calculate’. Each requires a slightly different level of detail.
最后，利用WJEC官网上的往年试题来熟悉指令词：“state”（陈述）、“describe”（描述）、“explain”（解释）和“calculate”（计算）。每种指令词要求的详细程度略有不同。
Regular revision in short bursts is more effective than cramming. Aim for 20–30 minutes of physics revision several times a week rather than a single long session.
短时间、多次数的定期复习比突击更有效。每周进行数次20–30分钟的物理复习，而非一次性长时间复习。
Published by TutorHao | Physics Revision Series | aleveler.com
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