Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Correct Answer: D. A data type constrains the values and operations valid for a variable
Explanation:
Types define representation and permitted operations, helping programs detect invalid use.
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Correct Answer: C. Testing seeks evidence about defects and behaviour but cannot prove the complete absence of defects
Explanation:
Testing samples behaviour against expectations; exhaustive proof is usually infeasible.
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Correct Answer: C. Encapsulation groups data with methods and controls access to internal state
Explanation:
Encapsulation supports modular design by hiding implementation details behind a defined interface.
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Correct Answer: C. A primary key uniquely identifies each row in a table
Explanation:
Primary-key values are unique and support reliable row identification and relationships.
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Correct Answer: A. Big-O notation describes how resource use grows with input size
Explanation:
Asymptotic notation characterises growth rates rather than exact machine-specific time.
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Correct Answer: A. A useful debugging process reproduces the fault, isolates causes and verifies the fix with tests
Explanation:
Reproduction, isolation and regression testing make a fix explainable and less likely to create new faults.
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Correct Answer: D. An operating system manages hardware resources and provides services to applications
Explanation:
Operating systems coordinate processes, memory, storage, devices and user/application interfaces.
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Correct Answer: B. A binary digit can represent one of two states, 0 or 1
Explanation:
Binary uses base two, so each bit has two possible values and positional weights are powers of two.
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Correct Answer: B. A useful debugging process reproduces the fault, isolates causes and verifies the fix with tests
Explanation:
Reproduction, isolation and regression testing make a fix explainable and less likely to create new faults.
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Correct Answer: D. A data type constrains the values and operations valid for a variable
Explanation:
Types define representation and permitted operations, helping programs detect invalid use.
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Correct Answer: D. Users and processes should receive only the permissions necessary for their tasks
Explanation:
Limiting permissions reduces the impact of mistakes and compromised accounts.
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Correct Answer: D. Testing seeks evidence about defects and behaviour but cannot prove the complete absence of defects
Explanation:
Testing samples behaviour against expectations; exhaustive proof is usually infeasible.
