Technology – MCQ – GK Questions

LAN (Local Area Network) connects devices within a limited area like home, office, or campus using Ethernet or Wi-Fi. Enables resource sharing (printers, files) and internet access. Contrasted with WAN (Wide Area Network) like internet that spans large geographic distances.

SDSC-SHAR (Satish Dhawan Space Centre - Sriharikota) is ISRO's primary launch port in Andhra Pradesh. Handles all satellite and human spaceflight launches from Indian soil. Named after former ISRO chairman. Strategic coastal location enables safe launch trajectories over Bay of Bengal.

Hashing (e.g., SHA-256) generates fixed-size digest to detect changes; any modification alters the hash. Digital Signatures combine hashing with asymmetric encryption to also verify sender identity and provide non-repudiation. Both ensure integrity; signatures add authentication and legal validity.

.xlsx is the default extension for Excel workbooks (XML-based format introduced in Office 2007). Older .xls format is binary. Other extensions: .docx (Word), .pptx (PowerPoint), .pdf (portable document). File extensions help OS identify appropriate applications for opening files.

Second Normal Form (2NF) requires: 1) Table is in 1NF, and 2) No partial dependency (non-key attributes must depend on entire primary key, not part of composite key). Eliminates redundancy from partial dependencies. Further normalization to 3NF removes transitive dependencies.

Bharat QR and UPI QR are interoperable standards allowing merchants to display a single QR code accepted by all UPI apps and card networks. Eliminates need for multiple QR stickers. NPCI's standardization promotes cashless adoption at small merchants with low-cost acceptance infrastructure.

ICMP-based DoS attacks include: Ping Flood (direct echo request flood), Smurf Attack (spoofed broadcast amplification), and variants. Mitigation: rate limiting ICMP, disabling broadcast responses, ingress filtering, and DDoS protection services. Network monitoring detects abnormal traffic patterns.

IoT sensors (strain gauges, accelerometers, temperature) embedded in infrastructure monitor stress, vibrations, and environmental conditions in real-time. Data analytics predict maintenance needs and prevent failures. Critical for smart cities, disaster resilience, and extending asset lifespan with predictive maintenance.

Lower frequency bands (like 700 MHz) have longer wavelengths that penetrate buildings and obstacles better, providing wider coverage with fewer towers. Higher bands (3.5 GHz, 26 GHz) offer higher capacity but shorter range, requiring denser infrastructure. 5G deployments use band combinations for coverage+capacity.

Switch operates at Data Link Layer (Layer 2), using MAC addresses to forward frames to specific ports within a LAN. More efficient than hubs (broadcast to all ports). Managed switches support VLANs, QoS, and security features. Routers operate at Layer 3 using IP addresses.

USB (Universal Serial Bus) is the standard port for keyboards, mice, and most peripherals. Replaced legacy PS/2 ports. USB-C offers reversible connector and higher power/data transfer. Wireless keyboards use Bluetooth or RF dongles, but USB remains universal for wired connections.

COUNT() returns the number of rows that match a specified condition. COUNT(*) counts all rows; COUNT(column) counts non-NULL values. Used with GROUP BY for segmented counts. Other aggregates: SUM (total), AVG (mean), MIN/MAX (extremes). Essential for reporting and analytics queries.

Inherence-based authentication uses biometric traits inherent to the user: fingerprint, iris, face, voice, or behavioral patterns. Part of multi-factor authentication (MFA). Advantages: hard to lose/share; challenges: privacy concerns, spoofing risks, and accessibility for disabled users.

VoIP (Voice over Internet Protocol) transmits voice calls as data packets over IP networks (internet, LAN). Examples: WhatsApp calls, Zoom, Skype, corporate PBX. Advantages: lower cost, integration with apps, advanced features. Quality depends on bandwidth, latency, and jitter management.

Anomaly detection uses: Supervised Learning (trained on labeled attacks), Unsupervised Learning (clustering normal vs abnormal patterns), and Reinforcement Learning (adaptive response to threats). Combined approaches improve detection of zero-day attacks and reduce false positives in SIEM systems.

UPI allows linking multiple bank accounts to one Virtual Payment Address (VPA). Users can select default account or choose at transaction time. Simplifies management, enables fund routing flexibility, and maintains single identity across banks. Managed securely via NPCI's central switch.

Caps Lock toggles alphabetic keys to produce uppercase letters without holding Shift. Shift produces uppercase only while pressed. Caps Lock indicator (LED) shows active state. Useful for typing headings or acronyms; accidental activation is a common user frustration.

JOIN combines rows from multiple tables using related columns (usually primary/foreign keys). Types: INNER JOIN (matching rows), LEFT/RIGHT JOIN (all rows from one side), FULL OUTER JOIN (all rows). Essential for normalized database queries retrieving related data across tables.

Disabling SSID broadcast hides network name from public scans, adding obscurity layer. However, strong security requires WPA3 encryption, complex password, MAC filtering, and regular firmware updates. WEP is broken; default passwords are easily guessable; open networks offer no protection.

UPI AutoPay enables mandate-based recurring payments for subscriptions (OTT, utilities, mutual funds). Users set amount, frequency, and validity; payments execute automatically without manual intervention each time. Enhances convenience while maintaining security with transaction limits and notifications.