Which cryptographic algorithm is currently recommended by NIST for symmetric encryption?
A DES (Data Encryption Standard) B AES (Advanced Encryption Standard) C MD5 D SHA-1
AES is the current NIST standard for symmetric encryption with key sizes of 128, 192, or 256 bits. DES is deprecated due to weak key size.
Which SQL JOIN returns only matching records from both tables?
A INNER JOIN B LEFT JOIN C RIGHT JOIN D FULL OUTER JOIN
INNER JOIN returns only the records that have matching values in both tables, filtering out non-matching rows.
In database indexing, which structure provides O(log n) search complexity?
A Linear search B B-Tree C Hash table with collision D Linked list
B-Tree maintains balanced structure ensuring O(log n) search, insert, and delete operations, commonly used in databases.
Which data structure is best for implementing a priority queue in heapsort algorithm?
A Stack B Queue C Heap D Array
A heap (min-heap or max-heap) efficiently supports priority queue operations with O(log n) insertion and deletion.
What is the main advantage of cloud computing's elasticity?
A Lower initial hardware cost B Automatic resource scaling based on demand C Guaranteed 100% uptime D Elimination of all security risks
Elasticity allows automatic resource provisioning and de-provisioning based on real-time demand, reducing costs.
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In SQL, what does the GROUP BY clause do?
A Joins multiple tables B Aggregates rows into groups based on specified columns C Deletes duplicate records D Orders results alphabetically
GROUP BY groups rows with identical values in specified columns, used with aggregate functions like COUNT(), SUM().
Which normalization form eliminates all non-key dependencies?
A 1NF B 2NF C 3NF D 4NF
3NF (Third Normal Form) ensures all non-key attributes depend only on the primary key, eliminating transitive dependencies.
What is the time complexity of quicksort algorithm in the worst case?
A O(n log n) B O(n²) C O(n) D O(log n)
Quicksort's worst-case complexity is O(n²) when pivot selection is poor, though average case is O(n log n).
In cloud computing, which service model allows customers to run their own applications but not manage infrastructure?
A IaaS B PaaS C SaaS D DBaaS
PaaS (Platform as a Service) provides a platform to develop and deploy applications without managing underlying infrastructure.
What is the difference between DELETE and TRUNCATE in SQL?
A DELETE is faster than TRUNCATE B TRUNCATE is DDL; DELETE is DML and is slower but can be rolled back C TRUNCATE cannot be rolled back while DELETE can D Both have identical functionality
TRUNCATE is DDL (immediate, cannot be rolled back in most databases), DELETE is DML (slower, can be rolled back).
In graph algorithms, which algorithm finds the shortest path in weighted graphs?
A DFS B BFS C Dijkstra's algorithm D Topological sort
Dijkstra's algorithm efficiently finds shortest paths from a source node to all other nodes in weighted graphs with non-negative weights.
What does normalization in machine learning context primarily aim to achieve?
A Reduce features to 2D B Scale features to similar ranges to improve model performance C Remove all outliers D Increase dataset size
Normalization scales features (e.g., 0-1 range) preventing features with larger scales from dominating model training.
In cybersecurity, what is SQL injection attack?
A Inserting legitimate SQL into database B Malicious SQL code injected into input fields to manipulate database queries C A method to optimize SQL performance D Splitting SQL statements across multiple lines
SQL injection exploits vulnerable input handling to execute unintended SQL commands, potentially exposing or modifying data.
What is the primary difference between supervised and unsupervised machine learning?
A Supervised uses labeled data; unsupervised uses unlabeled data B Unsupervised is faster than supervised C Supervised cannot predict outcomes D Unsupervised requires human supervision
Supervised learning trains on labeled data (features + targets); unsupervised finds patterns in unlabeled data without predefined outputs.
In distributed systems, what is a consensus algorithm primarily used for?
A Encrypting data B Ensuring all nodes agree on a single value despite failures C Compressing database files D Load balancing across servers
Consensus algorithms (like Raft, Paxos) enable distributed systems to reliably agree on state even with node failures.
What is the primary challenge of implementing ACID properties in distributed databases?
A Requires minimal network latency B Network partitions, latency, and node failures make maintaining consistency difficult while ensuring availability C Distributed systems automatically ensure ACID D Only centralized databases can support ACID
The CAP theorem shows it's impossible to guarantee all three: Consistency, Availability, and Partition tolerance simultaneously.
In AI/ML, what is the role of activation functions in neural networks?
A Encrypt network weights B Introduce non-linearity enabling networks to learn complex patterns C Increase training speed D Reduce dataset size
Activation functions (ReLU, sigmoid, tanh) add non-linearity, allowing neural networks to approximate non-linear relationships.
In a relational database, which normal form eliminates partial dependencies and is considered essential for most practical database designs?
A Second Normal Form (2NF) B Third Normal Form (3NF) C Boyce-Codd Normal Form (BCNF) D Fourth Normal Form (4NF)
3NF eliminates partial and transitive dependencies, making it the standard for practical database design. BCNF is stricter but 3NF is the most commonly implemented normalization form.
Which of the following is a characteristic of NoSQL databases that makes them suitable for handling big data in cloud environments?
A Strict ACID compliance across all nodes B Horizontal scalability and schema-less design C Requirement for predefined schemas before insertion D Complex JOIN operations for data retrieval
NoSQL databases like MongoDB and Cassandra are designed for horizontal scaling and flexible schemas, making them ideal for cloud-based big data applications with varying data structures.
In database indexing, which type of index structure provides the best average-case performance for range queries in modern database systems?
A Hash Index B B+ Tree Index C Bitmap Index D Full-text Index
B+ Tree indexes maintain sorted order and support efficient range queries, point queries, and prefix searches. Hash indexes are faster for exact matches but cannot handle range queries efficiently.
