AS Level Free Diagnostic

Data Representation

1Which statement best describes Binary prefixes and magnitudes?

AOne’s complement inverts every bit; two’s complement inverts then adds one and provides a single zero representation.BBCD stores each denary digit in four bits; hexadecimal groups binary into nibbles and is useful for addresses, colours and diagnostics.CBitmap images encode pixels, vector graphics encode drawing objects, and digital sound encodes sampled amplitude measurements.DKibi, mebi, gibi and tebi use powers of 1024, while kilo, mega, giga and tera use powers of 1000.

Communication

2Which statement best describes Topologies and media?

APhysical and logical arrangements affect resilience, performance and cost; wired and wireless media have different bandwidth and interference characteristics.BMAC addresses identify interfaces locally, IP addresses support routed communication and DNS maps domain names to IP addresses.CProtocols such as TCP, IP, HTTP, HTTPS, FTP and email protocols define formats, sequencing, addressing and error handling.DPackets pass through routers between networks; services use ports and application protocols above the underlying network transport.

Hardware

3Which statement best describes Storage technologies?

AScanners, sensors, touch systems and direct-entry devices convert real-world data into signals a computer can process.BMagnetic, optical and solid-state devices use different physical mechanisms and trade speed, capacity, longevity and cost.CAn embedded system is built into a larger product for a limited, dedicated function, often under strict cost, power and reliability constraints.DLogic gates combine binary conditions to control hardware, and truth tables verify the output for every input combination.

Computer Architecture

4Which statement best describes Assembly language?

AThe ALU, control unit, registers, buses and memory interface work together in a stored-program architecture.BPC, MAR, MDR, CIR, accumulator and index register have distinct roles during fetch and execution.CMnemonic instructions, labels and symbolic operands represent machine operations in a readable low-level form.DBitwise AND, OR and XOR combine masks with data; shifts multiply, divide or isolate bit fields when overflow is controlled.

System Software

5Which statement best describes Interpreter and assembler?

AThe OS manages processes, memory, files, devices, security and user interaction while providing services to application programs.BThe OS allocates and protects memory, tracks free space and may use virtual memory when physical RAM is insufficient.CDrivers translate general OS requests into commands for a particular hardware device; interrupts report events requiring attention.DAn interpreter translates and executes incrementally; an assembler converts mnemonics and symbolic labels to machine code.

Security

6Which statement best describes Threats and vulnerabilities?

APasswords, biometrics, tokens and multi-factor authentication establish identity; permissions restrict what an authenticated user may do.BEncryption transforms plaintext using a key so intercepted ciphertext is not useful without the appropriate decryption key.CValidation, verification, checksums, hashing, audit logs and database constraints help detect or prevent unintended change.DMalware, social engineering, weak credentials, unpatched software and insecure networks create different routes to compromise.

Computer Ethics

7Which statement best describes Intellectual property?

ACopyright, licences and attribution define how software and digital works may be used, shared or modified.BDevelopers should test honestly, disclose risks, protect users and avoid designing systems that foreseeably cause harm.CCost, location, disability, language and skills can prevent equal access; inclusive design reduces avoidable barriers.DAlgorithms may scale bias or obscure accountability, so meaningful oversight, explainability and routes to challenge are important.

Database

8Which statement best describes Normalisation?

ATables model entities, rows represent occurrences and columns represent attributes with defined domains and data types.BNormalisation separates repeating groups and dependencies so each fact is stored in an appropriate place with less duplication.CA DBMS provides controlled access, query processing, security, backup, recovery, concurrency and a data dictionary.DDDL creates or changes database structures; DML retrieves and modifies stored data through commands such as SELECT, INSERT, UPDATE and DELETE.

Sequence

9Which statement best describes Input, processing and output?

AVariables name storage whose value may change; constants name values that should remain fixed during execution.BInteger, real, Boolean, character and string types determine valid values, operations and storage behaviour.CA clear algorithm validates input assumptions, performs ordered calculations and formats output with meaningful labels.DA trace records each variable change and reveals wrong order, incorrect initialisation and unintended overwriting.

Built-in Functions

10Which statement best describes Type conversion?

ALength returns a character count; substring operations extract a defined section using a starting position and length or end position.BUppercase and lowercase conversion support case-insensitive comparison while preserving the original value when needed.CCharacter-to-code and code-to-character functions connect textual data with the numeric encoding used internally.DExplicit conversion changes a value between compatible representations and should occur only after input has been checked.