📚 Year 8 OCR Computing: Unit Test Mock Paper Walkthrough | 8年级OCR计算机：单元测试模拟卷解析
Welcome to this detailed walkthrough of a Year 8 OCR Computing unit test mock paper. The questions presented here reflect typical topics you will encounter: binary and denary conversion, storage units, flowchart symbols, Python basics, algorithms, hardware, networking fundamentals, and e‑safety. Each section contains a sample question, followed by a step‑by‑step explanation in both English and Chinese. Use this resource to check your understanding, identify gaps, and build confidence before your real test.
欢迎阅读这份8年级OCR计算机单元测试模拟卷的详细解析。这里呈现的题目反映了你会遇到的典型主题：二进制与十进制转换、存储单位、流程图符号、Python基础、算法、硬件、网络基础知识和网络安全。每个部分都包含一个示例题目，随后提供中英文逐步解析。利用这份资源来检查自己的理解、找出薄弱环节，并在真正考试前建立信心。
1. Binary to Denary Conversion | 二进制转十进制
Question: Convert the 8‑bit binary number 01101001₂ into its denary equivalent. Show your working.
题目：将8位二进制数01101001₂转换为十进制，写出计算过程。
To convert, write the place values for an 8‑ ×4 = 0, 0×2 = 0, 1×1 = 1. Add the results: 64 + 32 + 8 + 1 = 105. The denary value is 105.
转换时，写出8位二进制数的位值：128、64、32、16、8、4、2、1。将各位对齐：0×128=0，1×64=64，1×32=32，0×16=0，1×8=8，0×4=0，0×2=0，1×1=1。将结果相加：64+32+8+1=105。因此十进制值为105。
2. Denary to Binary Conversion | 十进制转二进制
Question: Represent the denary number 78 as an 8‑bit binary number. You must show the steps of successive division by 2.
题目：将十进制数78表示为8位二进制数，必须写出连续除以2的步骤。
Divide 78 by 2: quotient 39, remainder 0. Divide 39: quotient 19, remainder 1. Divide 19: quotient 9, remainder 1. Divide 9: quotient 4, remainder 1. Divide 4: quotient 2, remainder 0. Divide 2: quotient 1, remainder 0. Divide 1: quotient 0, remainder 1. Reading remainders from bottom to top gives 1001110₂. Pad to 8 bits by adding a leading zero: 01001110₂.
78除以2：商39，余0。39除以2：商19，余1。19除以2：商9，余1。9除以2：商4，余1。4除以2：商2，余0。2除以2：商1，余0。1除以2：商0，余1。从下往上读取余数得到1001110₂。补足8位，在前面加0：01001110₂。
3. Units of Digital Storage | 数字存储单位
Question: in megabytes (MB). Use the binary definitions where 1 KB = 1024 bytes and 1 MB = 1024 KB.
题目：一张照片的文件大小为3,145,728字节。用千字节（KB）和兆字节（MB）表示该值。采用二进制定义：1KB=1024字节，1MB=1024KB。
y 1024 to find MB: 3072 ÷ 1024 = 3 MB. Therefore the file size is 3072 KB or exactly 3 MB.
首先，将字节数除以1024得到KB：3,145,728÷1024=3072KB。然后，将KB除以1024得到MB：3072÷1024=3MB。因此文件大小为3072KB或正好3MB。
4. Flowchart Symbols and Sequence | 流程图符号与顺序
Question: Draw and label the flowchart symbols for Start/End, Process, and Decision. Then, arrange these steps into a simple flowchart for an alarm clock: (1) Check if current time equals alarm time; (2) If yes, sound alarm for 1 minute; (3) If no, keep waiting; (4) End.
题目：画出并标注开始/结束、处理和判断的流程图符号。然后，按照以下步骤为闹钟制作一个简单的流程图：（1）检查当前时间是否等于闹钟时间；（2）如果是，响铃1分钟；（3）如果否，继续等待；（4）结束。
e flowchart: Start (oval) → Process: Get current time (rectangle) → Decision: Time = alarm? (diamond). The 'Yes' branch goes to Process: Sound alarm for 1 min (rectangle) → End (oval). The 'No' branch goes back to the Process: Get current time, creating a loop. This shows sequence, selection, and iteration.
开始/结束是椭圆形，处理是矩形，判断是菱形。流程图：开始（椭圆）→ 处理：获取当前时间（矩形）→ 判断：时间=闹钟？（菱形）。“是”分支走向处理：响铃1分钟（矩形）→ 结束（椭圆）。“否”分支返回到处理：获取当前时间，形成循环。这展示了顺序、选择和迭代。
5. Variables and Data Types in Python | Python中的变量与数据类型
Question: A program uses the following code: name = "Ayesha" ; age = 13 ; height = 1.58 ; likes_pizza = True . Identify the data type of each variable. What would type(name) return?
题目：某程序使用了如下代码：name = "Ayesha"；age = 13；height = 1.58；likes_pizza = True。指出每个变量的数据类型。type(name)会返回什么？
The data types are: name is a string (str), age is an integer (int), height is a float, and likes_pizza is a boolean (bool). In Python, type(name) evaluates to
数据类型分别为：name是字符串（str），age是整数（int），height是浮点数（float），likes_pizza是布尔值（bool）。在Python中，type(name)会返回
6. Simple Python Arithmetic and Output | 简单Python算术与输出
Question: What output is produced by the following Python code? x = 7 ; y = 3 ; print(x + y * 2) ; print((x + y) * 2) . Explain the difference due to operator precedence.
题目：以下Python代码会输出什么？x = 7；y = 3；print(x + y * 2)；print((x + y) * 2)。解释由于运算符优先级造成的差异。
Multiplication has higher precedence than addition. So x + y * 2 10×2 = 20. The second print outputs 20. Thus the outputs are 13 and 20 on separate lines.
乘法的优先级高于加法。因此x + y * 2按7+(3×2)=7+6=13计算，第一条print输出13。第二行中，括号强制先做加法：(7+3)=10，再10×2=20，第二条print输出20。所以输出结果为两行：13和20。
7. Input, Process, Output (IPO) Model | 输入-处理-输出模型
Question: A friend is designing a currency converter app. The user enters an amount in pounds (£) and the program displays the equivalent in euros. Identify the input, the process, and the output. Then write a simple algorithm in pseudocode.
题目：一位朋友正在设计一个货币转换器应用。用户输入英镑金额，程序显示等值的欧元。指出输入、处理和输出，并用伪代码写出一个简单算法。
Input: the amount in pounds (a real number). Process: multiply the pounds amount by the exchange rate (e.g., 1.15). Output: the amount in euros. Pseudocode:
BEGIN
INPUT pounds
SET rate = 1.15
SET euros = pounds × rate
OUTPUT euros
END
输入：英镑金额（一个实数）。处理：将英镑金额乘以汇率（例如1.15）。输出：欧元金额。伪代码：
开始
输入 pounds
设置 rate = 1.15
设置 euros = pounds × rate
输出 euros
结束
8. Identifying Input and Output Devices | 识别输入与输出设备
Question: Classify each item as an input device, output device, or storage device: barcode scanner, projector, SSD, touchscreen, headphones, microphone.
题目：将下列设备分类为输入设备、输出设备或存储设备：条码扫描器、投影仪、固态硬盘（SSD）、触摸屏、耳机、麦克风。
A barcode scanner is an input device (reads data). A projector is an output device (displays visuals). An SSD is a storage device (holds data permanently). A touchscreen is both an input and output device — it displays output and accepts touch input. Headphones are output devices (produce sound). A microphone is an input device (captures sound).
条码扫描器是输入设备（读取数据）。投影仪是输出设备（显示图像）。固态硬盘是存储设备（永久保存数据）。触摸屏既是输入也是输出设备——它显示输出并接受触摸输入。耳机是输出设备（发出声音）。麦克风是输入设备（捕捉声音）。
9. Understanding Computer Networks | 理解计算机网络
Question: A school has 50 computers connected in a LAN. Explain the difference between a switch and a router. Why does the school need a router to access BBC Bitesize?
题目：某学校有50台计算机连接成一个局域网（LAN）。解释交换机和路由器的区别。为什么学校需要路由器才能访问BBC Bitesize？
A switch connects devices within the same LAN, forwarding data only to the intended recipient using MAC addresses. A router connects different networks together, such as the school LAN to the internet. To access BBC Bitesize, which is hosted on servers outside the school network, traffic must be sent through the router, which routes packets to the wider internet.
交换机连接同一局域网内的设备，使用MAC地址仅将数据转发给目标接收者。路由器连接不同的网络，例如学校局域网和互联网。要访问BBC Bitesize（其服务器位于学校网络之外），流量必须通过路由器发送，路由器将数据包路由到更广的互联网。
10. E‑safety and Strong Passwords | 网络安全与强密码
Question: Explain three characteristics of a strong password. Your friend uses 'password123' for their email account. Give two risks and suggest a better password.
题目：解释强密码的三个特征。你的朋友用'password123'作为邮箱密码。给出两种风险并建议一个更好的密码。
A strong password should: be at least 8–12 characters long, include a mix of upper‑case and lower‑case letters, numbers, and symbols (e.g., @, !, #), and avoid dictionary words or personal information. The password 'password123' is extremely weak: it uses a common dictionary word and a predictable number sequence. Risks include brute‑force attacks and credential stuffing. A better password could be 'Tr33@pple#19', which is long, not a real word, and mixes character types.
强密码应该：至少8–12个字符长，包含大小写字母、数字和符号（如@、!、#）的混合，并避免使用字典单词或个人信息。密码'password123'非常弱：它使用常见字典单词和可预测的数字序列。风险包括暴力破解和撞库攻击。一个更好的密码可以是'Tr33@pple#19'，它较长，不是真实单词，且混合了多种字符类型。
11. Debugging a Simple Python Program | 调试一个简单的Python程序
Question: The code below is meant to ask for a number and print its double, but it contains errors. Identify and fix them.
num = input("Enter a number:")
dubble = Num * 2
print("Double is" + dubble)
题目：以下代码本应要求输入一个数字并输出其两倍，但包含错误。找出并修正它们。
num = input("Enter a number:")
dubble = Num * 2
print("Double is" + dubble)
Error 1: input() returns a string; we must convert it to an integer or float: num = int(input(...)) . Error 2: variable names are case‑sensitive — it uses Num instead of num. Error 3: variable name dubble is misspelt but that's not a syntax error; still correct it if desired. Error 4: cannot directly concatenate a number with a string in print; use a comma or convert the number: print("Double is", dubble) or print("Double is " + str(dubble)). Corrected code:
num = int(input("Enter a number: "))
double = num * 2
print("Double is", double)
错误1：input()返回字符串；必须将其转换为整数或浮点数：num = int(input(...))。错误2：变量名区分大小写——它使用了Num而不是num。错误3：变量名dubble拼写错误，但这并非语法错误；如果需要可以修正。错误4：在print中不能直接将数字与字符串用+连接；应使用逗号或将数字转换为字符串：print("Double is", dubble)或print("Double is " + str(dubble))。修正后的代码：
num = int(input("Enter a number: "))
double = num * 2
print("Double is", double)
12. Computational Thinking: Decomposition | 计算思维：分解
Question: You are asked to plan a Year 8 school trip for 120 students. Explain how decomposition helps you break down the problem. Give three sub‑problems you would identify.
题目：你被要求为120名学生策划一次8年级学校旅行。解释分解如何帮助你拆解问题。列出你会划分出的三个子问题。
Decomposition means breaking a large, complex problem into smaller, more manageable parts. For the school trip, sub‑problems could include: (1) Transport: booking coaches and calculating cost per student; (2) Venue and activities: selecting a suitable location and scheduling activities; (3) Permissions and safety: collecting consent forms and planning first‑aid cover. Each sub‑problem can be tackled independently, making the overall task easier.
分解是指将一个庞大而复杂的问题拆分成更小、更易管理的部分。对于学校旅行，子问题可以包括：（1）交通：预订大巴并计算每名学生费用；（2）场地与活动：选择合适地点并安排活动；（3）许可与安全：收集家长同意书并规划急救措施。每个子问题可以独立处理，使整体任务变得更容易。
Published by TutorHao | Computing Revision Series | aleveler.com
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