Computer Knowledge — MCQ Practice Questions & Answers

Question 1

What is a deadlock in database management?

Accepted Answer

Correct answer: A. A situation where transactions block indefinitely waiting for each other — A deadlock occurs when two or more transactions wait for resources held by each other, creating a circular wait condition that prevents progress.

Answer

B. Loss of database connection

Answer

C. Unauthorized access to database

Answer

D. Corruption of data files

Question 2

Which of the following best describes eventual consistency in distributed databases?

Accepted Answer

Correct answer: B. Data will be consistent across all nodes eventually, not immediately — Eventual consistency is a model in NoSQL and distributed systems where updates propagate asynchronously, achieving consistency over time rather than immediately.

Answer

A. All nodes have identical data at all times

Answer

C. Data consistency is never achieved

Answer

D. Only primary nodes maintain consistency

Question 3

In network protocols, which layer does TCP/IP operate at?

Accepted Answer

Correct answer: C. Transport and Network Layers — TCP operates at Layer 4 (Transport) and IP at Layer 3 (Network) in the OSI model. Together they form the TCP/IP protocol suite.

Answer

A. Physical Layer

Answer

B. Data Link Layer

Answer

D. Application Layer only

Question 4

What is the primary vulnerability addressed by SQL injection prevention techniques like parameterized queries?

Accepted Answer

Correct answer: B. Injection of malicious SQL code into database queries — Parameterized queries prevent SQL injection by separating query structure from data, ensuring user input cannot be interpreted as executable code.

Answer

A. Buffer overflow attacks

Answer

C. Man-in-the-middle attacks

Answer

D. DDoS attacks on database server

Question 5

In the context of graph databases, what is the primary advantage over relational databases for relationship-heavy queries?

Accepted Answer

Correct answer: B. Faster execution of complex relationship traversals — Graph databases excel at querying relationships with O(1) traversal time, whereas relational databases require expensive JOIN operations for similar queries.

Answer

A. Lower storage requirements

Answer

C. Better support for unstructured data

Answer

D. Superior ACID compliance

Question 6

What does CAP theorem state in distributed systems?

Accepted Answer

Correct answer: A. A system can guarantee at most 2 of 3: Consistency, Availability, Partition tolerance — CAP theorem (Brewer's theorem) states distributed systems must choose 2 of 3 properties: strong consistency (C), continuous availability (A), or tolerance to network partitions (P).

Answer

B. All distributed systems must be Consistent, Available, and Partition-tolerant

Answer

C. Consistency requires Availability and Partitions

Answer

D. Availability is always achieved in partitioned systems

Question 7

In cybersecurity, what is a zero-day vulnerability?

Accepted Answer

Correct answer: A. A security flaw unknown to vendors with no patch available — Zero-day vulnerabilities are previously unknown exploits with no patch. They're extremely dangerous because users have no defense until vendors develop and release fixes.

Answer

B. A vulnerability found on the first day of software release

Answer

C. A virus that activates at midnight

Answer

D. A type of brute-force attack

Question 8

What does BASE model in NoSQL stand for?

Accepted Answer

Correct answer: A. Basically Available, Soft state, Eventually consistent — BASE is an alternative to ACID, prioritizing availability and partition tolerance. It accepts temporary inconsistencies that resolve eventually (eventual consistency).

Answer

B. Batch Available, System Events, Eventual consistency

Answer

C. Buffer Availability, Strong consistency, Event-driven

Answer

D. Backup Availability, Security-first, Efficient

Computer Knowledge - MCQ Practice Questions