Computer Science MCQ with detailed explanations for students & freshers preparing for entrance exams, various tests, interviews, competitive exams like GATE exam, interview, competitive examination and entrance exam.
B.To determine whether a machine can exhibit human-like intelligence
C.To encrypt wireless network traffic
D.To find bugs in compile-time code
Correct answer is:
B. To determine whether a machine can exhibit human-like intelligence
Proposed by Alan Turing in 1950, the Turing Test remains a foundational concept in the philosophy of artificial intelligence.
The primary purpose of the test is to determine whether a machine can exhibit human-like intelligence through natural language conversation, evaluating if a human judge cannot reliably tell the machine apart from a human participant.
It does not measure hardware compute speeds, database transactional latency, encryption robustness, or software compilation debugging.
When deploying updates to enterprise software systems, organizations utilize safe transition strategies to mitigate operational risks.
Parallel Testing (or parallel conversion) involves running both the old system and the new system simultaneously for a set period to compare outputs and ensure the new infrastructure is stable and accurate.
By contrast, Direct Changeover switches instantly, Pilot Testing introduces the system to a single localized department first, and Phased Conversion replaces modules step-by-step.
Relational database management systems (RDBMS) are built upon the foundational mathematical concepts of relational algebra.
In formal relational model terminology, rows in a table are technically called tuples, representing a single, structured data record.
Correspondingly, columns are referred to as attributes, fields represent individual data cells, and keys are constraints utilized to enforce unique identification or relational links.
The National Institute of Standards and Technology (NIST) outlines the core characteristics that define true cloud computing models.
Location dependency is NOT a standard characteristic; cloud computing relies explicitly on location independence, allowing services to be accessed globally regardless of where physical data centers reside.
Standard characteristics include on-demand self-service, resource pooling, and rapid elasticity to scale resources fluidly based on current workload volumes.
B.Reduces file size and storage/transmission requirements
C.Improves data security protocols
D.Converts text files into executable formats
Correct answer is:
B. Reduces file size and storage/transmission requirements
Data compression utilizes mathematical algorithms to restructure data files more efficiently by reducing or removing redundancy.
The primary effect and benefit of this process is that it reduces file size and storage/transmission requirements, optimizing disk space usage and speeding up network transfer times.
It is completely separate from security encryption protocols, it decreases rather than increases resource load over networks, and it does not transform static text files into executable code binaries.
Network communications rely on numerical IP addresses, whereas humans interact more efficiently using text-based domain names.
The DNS (Domain Name System) protocol serves as the directory of the internet, resolving human-readable domain names (e.g., www.example.com) into machine-readable IP addresses.
The other protocols serve different application layers: HTTP manages web content delivery, FTP handles file transfers, and SMTP routes email transmissions.
C.Enhance storage performance by distributing data across multiple drives
D.Enhance network security
Correct answer is:
C. Enhance storage performance by distributing data across multiple drives
RAID stands for Redundant Array of Independent Disks (originally Inexpensive Disks). Its primary purpose is to enhance storage performance by distributing data across multiple drives. By doing so, RAID can offer several benefits:
Improved performance: Data can be read from or written to multiple disks simultaneously.
Data redundancy/fault tolerance: In some RAID levels, data is duplicated or parity information is stored, allowing data to be recovered even if one or more drives fail.
An Ethernet card, which is used to set up a wired network connection, is also commonly known as a Network Interface Card (NIC). The NIC is a hardware component that allows a computer to connect to a network using a wired connection, typically via an Ethernet cable.
This is an analogy question. A lock provides security or access control for a door. Similarly, a password provides security or access control for a computer (or an account/system within a computer). Just as a lock restricts physical entry, a password restricts digital access.
The primary purpose of indexing in databases is to speed up data search and retrieval operations. An index is a special lookup table that the database search engine can use to quickly find data. Much like an index in a book, it points to the location of specific data records without having to scan the entire table, significantly reducing query execution time for large datasets.
A Worm is a standalone malware computer program that replicates itself in order to spread to other computers. It often uses a computer network to spread itself, relying on security vulnerabilities on the target computer to access it. Unlike a virus, a worm does not need to attach itself to an existing program or require user interaction to spread.
Virus: Requires a host program and user action to execute and spread.
Trojan: Disguises itself as legitimate software but carries out malicious activities, relying on user deception.
Spyware: Gathers information about a person or organization without their knowledge and transmits it to another entity.
In computer operating systems, checkpoints are critical for the recovery process. A checkpoint is a point in time where the state of a system or application is saved. This allows the system to be restored to that specific state in case of a failure, preventing loss of data or progress and facilitating a quicker recovery.
In Microsoft PowerPoint, a presentation is fundamentally a collection of slides. Each slide is an individual page that can contain text, images, charts, videos, and other multimedia elements, all organized to convey information or a message to an audience.
The correct answer is D: .pdf. While Microsoft Excel can export data to a PDF (Portable Document Format) file, .pdf is not a native or valid Microsoft Excel *file format* for storing editable spreadsheet data. PDF is a universal file format used to present documents in a manner independent of application software, hardware, and operating systems. When you save an Excel sheet as a PDF, it essentially creates a snapshot or print-ready version, not a functional spreadsheet file that can be fully reopened and edited in Excel with all its formulas and sheet structure intact.
A: .xlsx is incorrect. .xlsx is the primary and default file format for Microsoft Excel documents starting from Excel 2007. It is an XML-based format that supports all modern Excel features.
B: .csv is incorrect. .csv (Comma Separated Values) is a widely used plain-text file format that stores tabular data in rows and columns, where each value is separated by a comma. Excel can open, edit, and save .csv files, making it a valid and common format for data exchange with Excel.
C: .xls is incorrect. .xls is the traditional file format for Microsoft Excel workbooks from Excel 97 to Excel 2003. Although superseded by .xlsx, it is still a valid and recognizable Excel file format that modern Excel versions can open and save.
The correct answer is B: 80. The HTTP (Hypertext Transfer Protocol) protocol, which is the foundation of data communication for the World Wide Web, works on port 80 by default. When you type a web address (e.g., http://www.example.com) into your browser without specifying a port number, your browser automatically attempts to connect to port 80 on the web server to retrieve the webpage. This standardization allows for seamless web browsing.
A: 21 is incorrect. Port 21 is the default port for FTP (File Transfer Protocol), which is used for transferring files between a client and a server on a computer network. It is not used for HTTP communication.
C: 25 is incorrect. Port 25 is the default port for SMTP (Simple Mail Transfer Protocol), which is used for sending and receiving email messages between email servers. It is not used for web browsing.
D: 443 is incorrect. Port 443 is the default port for HTTPS (Hypertext Transfer Protocol Secure). HTTPS is the secure version of HTTP, using SSL/TLS encryption to secure communication over a computer network. While related to web browsing, it is for secure connections, whereas HTTP's default is port 80 for unencrypted communication.
The correct answer is C: Protocol Network. Protocols are sets of rules that define how data is formatted, transmitted, received, and processed during communication between computers or devices in a network. They establish common ground and ensure that all participating devices can understand and interpret the exchanged information. Without protocols, computers would be unable to communicate effectively or meaningfully, leading to chaos in data transmission.
A: Hardware is incorrect. Hardware refers to the physical components of a computer system, such as network cards, routers, and cables. While hardware is essential for establishing physical connections and transmitting signals, it does not define the logical rules for how information is structured and interpreted during communication.
B: Operating System is incorrect. An operating system (OS) is software that manages computer hardware and software resources and provides common services for computer programs. While an OS implements network protocols, it doesn't *define* the universal rules for communication between *all* computers across a network; protocols do that independently of specific OS implementations.
D: Software is incorrect. Software is a broad term encompassing all programs and applications that run on a computer. While network protocols are implemented in software, the term "software" alone is too general. It doesn't specifically pinpoint the defining rules for communication between computers in the way that "Protocol Network" (or simply "Protocol" in this context) does.
The correct answer is ICMP because it is not a routing protocol. ICMP, or Internet Control Message Protocol, is primarily used for diagnostic purposes and to send error messages or operational information indicating success or failure when communicating with another IP address. For example, the 'ping' command uses ICMP echo requests and replies to check host reachability. While it's essential for network troubleshooting and management, ICMP does not determine the optimal paths for data packets to traverse networks, which is the fundamental role of routing protocols. Routing protocols, conversely, build and maintain routing tables that specify where to forward data packets to reach their destination networks.
RIP (Routing Information Protocol) is an actual routing protocol, specifically an interior gateway protocol (IGP). It uses hop count as its primary metric to find the best path for data packets within an autonomous system (AS).
BGP (Border Gateway Protocol) is also a routing protocol, serving as the exterior gateway protocol (EGP) for routing between different autonomous systems on the internet. It makes routing decisions based on paths, network policies, or predefined rule sets.
OSPF (Open Shortest Path First) is another true routing protocol and an IGP that uses a link-state routing algorithm. It constructs a topological map of the network and calculates the shortest path to each destination, making it more efficient and scalable than RIP in larger networks.
The correct answer is Telnet. Telnet is an application layer protocol used to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. It allows a user on one computer to log into another computer on the same network or the internet and execute commands as if they were directly connected to that machine. It provides a command-line interface for remote access, making it the specific service for remote terminal connections.
FTP (File Transfer Protocol) is incorrect because it is designed for transferring files between computers. While it facilitates remote access to files, it does not provide a general-purpose remote terminal connection for executing commands.
UDP (User Datagram Protocol) is incorrect because it is a transport layer protocol, not an application layer service for remote login. UDP provides a connectionless, unreliable datagram service, meaning it sends data packets without establishing a connection or guaranteeing delivery. It is a transport mechanism, not a remote login application itself.
RARP (Reverse Address Resolution Protocol) is incorrect because its purpose is to enable a host to discover its own Internet Protocol (IP) address when it only knows its Media Access Control (MAC) address. It has no function related to remote terminal connections or logging into other computers.
The correct answer is Process Layer. The OSI (Open Systems Interconnection) model is a conceptual framework that standardizes the functions of a telecommunication or computing system into seven distinct layers. The 'Process Layer' is not one of these standard layers. The OSI model layers are specifically defined to handle different aspects of network communication, from the physical transmission of data to the application-specific interactions.
Physical Layer is Layer 1 of the OSI model. It deals with the physical connection between devices, including cables, connectors, voltage levels, and the raw transmission of bits.
Transport Layer is Layer 4 of the OSI model. It is responsible for end-to-end communication between hosts, including segmentation, reassembly, flow control, and error handling for reliable data transfer (e.g., TCP, UDP).
Network Layer is Layer 3 of the OSI model. It handles logical addressing (IP addresses), routing packets across different networks, and forwarding data between hosts that are not directly connected (e.g., IP).
The actual seven layers of the OSI model are Physical, Data Link, Network, Transport, Session, Presentation, and Application layers. The term 'Process Layer' does not align with this standardized structure.
In operating systems, checkpoints are crucial for the recovery process. A checkpoint involves saving the complete state of a system or application at a specific moment. This saved state serves as a reliable point from which the system can restart or revert to in the event of a system crash or failure, thereby minimizing data loss and enabling quicker system restoration.
The correct answer is Asymmetric Key cryptography. Asymmetric key cryptography, also known as public-key cryptography, is a cryptographic system that uses pairs of keys: a public key, which can be widely distributed, and a private key, which is known only to the owner. Data encrypted with the public key can only be decrypted with the corresponding private key, and vice-versa. This unique design allows for secure communication and digital signatures without the need for a prior secure exchange of a shared secret key, fundamentally solving the key distribution problem inherent in other cryptographic methods. It is the backbone of many secure internet communications, including TLS/SSL protocols.
Hash cryptography is incorrect because hash functions are one-way mathematical algorithms that produce a fixed-size output (a hash value) from an input of arbitrary size. They are used for data integrity verification and password storage but do not involve a pair of public and private keys for encryption and decryption.
Symmetric Key cryptography is incorrect because it uses a single, secret key for both encryption and decryption. Both the sender and receiver must possess this same key, which requires a secure method for key exchange prior to communication.
Quantum cryptography is incorrect because it is an emerging field that uses principles of quantum mechanics, such as superposition and entanglement, to provide secure communication. While it aims to offer stronger security, it describes a different underlying mechanism for key generation and distribution, rather than the specific public/private key pair structure described in the question.
An External database generally refers to a database that is located and managed on a separate system or external server, rather than being embedded within or directly controlled by the application accessing it. Applications connect to these external databases over a network to store and retrieve data.
The correct answer is Star Topology. In a star topology, all network devices are connected to a single central device, such as a hub, switch, or router. This central component is crucial because all data communication between any two nodes in the network must pass through it. Consequently, if this central device experiences a failure, becomes overloaded, or is targeted by a Denial of Service (DoS) attack, the entire network segment connected to it will cease to function. This makes the central device the single point of failure, meaning its compromise can bring down the entire network, making the star topology most susceptible to widespread disruption from such an event.
Mesh Topology is incorrect. In a mesh topology, every device is connected to every other device, providing multiple redundant paths for data. This design is highly fault-tolerant; the failure of a single node or link typically does not disrupt the entire network, as traffic can be rerouted.
Bus Topology is incorrect. In a bus topology, all devices share a single communication line (the bus). While a break in the main bus cable can disrupt the entire network, there isn't a single central active device like a hub that processes all traffic. Individual node failures do not necessarily affect the whole network.
Ring Topology is incorrect. In a ring topology, each device is connected to exactly two other devices, forming a closed loop. While a single point of failure (a cable break or device failure) can disrupt a simple unidirectional ring, some implementations (like dual rings or token ring networks) offer redundancy to mitigate this. However, the question specifically refers to a central point of failure via a DoS attack on a hub, which is characteristic of a star.
In the context of a relational database model, a table is also commonly referred to as a Relation. Each table represents a collection of related data and is structured into rows (tuples) and columns (attributes), defining relationships between different data entities.
The correct answer is the Transport Layer. The Transport Layer (Layer 4) of the OSI model is responsible for providing end-to-end communication services between applications running on different hosts. Its primary functions include segmenting data from the application layer, multiplexing data from multiple applications into a single stream, flow control to prevent overwhelming the receiver, and most importantly, error handling. Protocols like TCP (Transmission Control Protocol) at this layer ensure reliable, ordered delivery of data, retransmitting lost or corrupted segments to guarantee that the application receives data accurately and completely from the other end.
Network Layer (Layer 3) is incorrect. This layer is responsible for logical addressing (IP addresses) and routing packets across different networks (host-to-host delivery). While it routes data packets, it does not manage the end-to-end communication or comprehensive error handling between applications themselves.
Session Layer (Layer 5) is incorrect. This layer establishes, manages, and terminates communication sessions between applications. It provides services like dialog control and synchronization, but it relies on the Transport Layer for the underlying reliable data transfer and error handling.
Data Link Layer (Layer 2) is incorrect. This layer is responsible for node-to-node data transfer within a single network segment or local area network. It handles framing, physical addressing (MAC addresses), and error detection/correction on a single link, but not end-to-end communication across an entire network path between disparate hosts.