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J277 1 Paper 1 diagnostic and misconception clinic
Part 5 of 5 · J277 Paper 1 · Exam transition
Six clinics on the Paper 1 misunderstandings that most often stop partial knowledge becoming marks.
Students will:
- diagnose the mistaken idea behind a tempting wrong answer
- restate the idea in precise specification language
- apply the corrected idea in a new context
- separate the pairs of terms that are most often confused
- record which clinics need revisiting
Inside: 8 explanation cells, 4 multiple-choice questions, 1 fill-in-the-blanks cell and 7 written answers. 26 marks, about 60 minutes.
Series: J277 Paper 1 · Exam transition, part 5 of 5.
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- 20 cells
- About 60 minutes
- CC BY-SA 4.0
- Shared 17 Aug 2026
- Updated 9 Sept 2026
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Paper 1 exam transition 5: diagnostic and misconception clinic
This worksheet targets misunderstandings that repeatedly prevent students from turning partial knowledge into marks. Each clinic follows the same cycle:
- diagnose the mistaken idea
- repair it using precise language
- apply the corrected idea in a new context
Record which clinics you need to revisit. The goal is not to catch you out; it is to make a tempting wrong answer less tempting next time.
Clinic 1: networks
Misconception: “A WAN has more computers than a LAN.”
Repair: LAN and WAN are distinguished mainly by geographical coverage and infrastructure, not by a fixed number of devices. A LAN covers a small site or local area and is usually owned/managed by one organisation. A WAN covers a large geographical area, connects networks and may use third-party infrastructure.
Misconception: “Wi-Fi is the Internet.”
Repair: Wi-Fi is a wireless way for a device to join a local network. The Internet is a worldwide collection of interconnected networks. A Wi-Fi network can exist without Internet access.
A school network covers one site and contains 900 devices. Which description is most accurate?
- AIt must be a WAN because it has more than 100 devices
- BIt can still be a LAN because it covers a local area
- CIt is the Internet because it uses Wi-Fi
- DIt cannot use switches
A tablet shows that it is connected to Wi-Fi, but websites do not load. Explain why these two facts can both be true. (2 marks)
Separate the local wireless connection from access to external networks.
Students type their answer here.
Clinic 2: addresses and hardware
Repair the pair: a switch connects devices and forwards data within a LAN; a router forwards data between networks. An IPv4 address contains four denary numbers from 0 to 255 separated by dots. A MAC address is assigned to a network interface and is commonly written as six pairs of hexadecimal digits.
DNS does not “send the website”. It finds the IP address associated with a domain name and returns that address so the client can contact the relevant server.
Which is a valid IPv4 address?
- A192.168.4.300
- BGG:21:44:9A:10:EF
- C192.168.4.27
- Dschool.example
Describe how DNS helps a browser reach museum.example after the user enters the domain name. (3 marks)
Give the request, lookup and returned result in order.
Students type their answer here.
Clinic 3: memory and storage
Misconception: “ROM is just another name for secondary storage.”
Repair: ROM is primary, non-volatile memory that stores instructions which should remain when power is removed, such as start-up firmware or fixed instructions in an embedded system. Secondary storage provides long-term storage for files, applications and user data. Both are non-volatile, but their role is different.
Misconception: “Virtual memory makes a computer faster.”
Repair: virtual memory allows work to continue when RAM is insufficient, but it uses slower secondary storage and can reduce performance.
A games console keeps start-up checks and fixed system instructions when unplugged. Explain why ROM is suitable. (3 marks)
Link non-volatility and fixed instructions to start-up.
Students type their answer here.
Why can frequent use of virtual memory slow a system?
- AROM loses its contents when power is removed
- BCache becomes a network
- CThe CPU stops using instructions
- DSecondary storage is slower to access than RAM
Clinic 4: CPU registers and operating systems
The MAR holds an address. The MDR holds data or an instruction being transferred. The PC holds the address of the next instruction. The ACC stores intermediate arithmetic or logic results. The ALU and control unit are CPU components, not registers.
For operating systems, distinguish:
- memory management: allocating memory and moving data as needed
- multitasking: scheduling processor time and resources among processes
- peripheral management: coordinating communication with devices
- drivers: software that lets the OS communicate with a particular device.
- ALU
- PC
- MDR
- control unit
- ACC
- MAR
A printer from a new manufacturer is connected to a laptop. Explain the role of its device driver. (2 marks)
Do not describe the driver as a cable.
Students type their answer here.
Clinic 5: data representation
- A pixel is one picture element and stores one colour value, not “many colours at once”.
- Higher image resolution means more pixels; higher colour depth means more bits per pixel.
- Higher sound sample rate means more samples each second; higher bit depth means more possible amplitude values for each sample.
- Binary addition working is shown with carries. A denary conversion may check the result but does not show binary working.
- A three-place left shift multiplies a value by 8 when no significant bit is lost, because each place doubles the value.
What does increasing the bit depth of a sampled sound recording directly change?
- AThe number of possible amplitude values for each sample
- BThe number of samples taken each second
- CThe number of pixels in each image
- DThe speed of the network switch
A student says, ‘A three-place left shift multiplies the value by 3.’ Correct the student and explain why. (2 marks)
Use powers of two or repeated doubling.
Students type their answer here.
Clinic 6: security and legal precision
Encryption can make intercepted data not understandable without the key, but it does not make interception impossible. A firewall filters network traffic; it does not repair every vulnerability. The Data Protection Act 2018 concerns the lawful, fair and secure processing of personal data. The Computer Misuse Act 1990 concerns unauthorised access and related unauthorised acts.
Choose the law or control that matches the action in the scenario rather than naming every law you remember.
An employee deliberately uses another person's password to enter an account without permission. Name the most relevant law and explain why it applies. (2 marks)
Name one law and connect it to the action.
Students type their answer here.
Challenge: Choose one misconception from this worksheet that you previously found convincing. Write a correct explanation and create a new scenario that would test the distinction. (4 marks)
Make the reflection scenario test the concept rather than repeat the wording above.
Students type their answer here.
Finish: use the diagnosis
Choose no more than three weak areas. Return to the relevant teaching worksheet, complete a short retrieval task without notes, then explain the corrected idea aloud or in writing. Focused repair is more useful than rereading every topic equally.