Technology – GK Questions

Flexbox handles one-dimensional layouts: arrange items in a row OR column with flexible sizing, alignment, and order. CSS Grid handles two-dimensional layouts (rows AND columns). Both are modern layout systems replacing floats/positioning. Understanding their use cases is important for responsive design questions.

man (manual) displays documentation for Linux commands, system calls, and configuration files. Example: man ls shows options and usage. help is for shell builtins; info provides hypertext docs; doc is not standard. Proficiency with man is essential for self-learning and troubleshooting in system administration.

CCS (Carbon Capture and Storage) captures CO2 from power plants/industries, transports it, and stores underground or uses in products (concrete, fuels). Critical for decarbonizing hard-to-abate sectors. India is developing CCS roadmap as part of net-zero strategy. Emerging topic for environment and technology exams.

CERT-In Direction 20 (April 2022) requires service providers including VPNs to maintain logs of customer registration and usage for 180 days, report cyber incidents within 6 hours, and synchronize with NTP. Aimed at enhancing incident response and law enforcement capabilities. Important for cybersecurity compliance questions.

Hash tables use hash functions to map keys to array indices, enabling average O(1) operations. Worst-case O(n) occurs with many collisions (resolved via chaining/open addressing). Load factor and good hash functions maintain performance. Critical data structure for efficient lookups in real-world applications and exams.

getElementById('id') returns the element with specified ID (case-sensitive). querySelector() uses CSS selectors for more flexibility. getElementsByClassName/TagName return collections. DOM manipulation is core to interactive web development and frequently tested in programming sections of exams.

ls -a lists all files including hidden ones (starting with .). ls -l shows detailed list; ls -h makes sizes human-readable; ls -la combines both. Hidden files store configuration data. Understanding command-line flags is fundamental for Linux administration questions in technical exams.

Panchamrit (five nectars) announced at COP26 includes: 500 GW non-fossil capacity by 2030 (updated from 450 GW), 50% energy from renewables, 1 billion tonne CO2 reduction, net-zero by 2070. National Solar Mission is a component; Green Energy Corridor enables transmission; Surya Mitra trains solar technicians.

Section 79 of IT Act provides safe harbor to intermediaries if they: (1) only provide access, (2) don't initiate/modify transmission, (3) observe due diligence and remove content upon actual knowledge. IT Rules 2021 add grievance redressal and traceability requirements. Critical for understanding platform liability.

Queue follows FIFO: first element added is first removed. Operations: enqueue (add rear), dequeue (remove front). Used in CPU scheduling, print spooling, breadth-first search. Stack follows LIFO. Understanding fundamental data structure behaviors is essential for programming exams.

CSS Box Model: content (actual text/image) → padding (space inside border) → border (edge around padding) → margin (space outside border). Understanding this model is crucial for layout design and responsive web development. Frequently tested in web technology sections of technical exams.

grep (global regular expression print) searches files for lines matching a pattern/string. Supports regex, recursive search, and context display. find locates files by name/path; locate uses a database; search is not a standard command. Essential for log analysis and text processing in system administration.

Green hydrogen is produced via water electrolysis powered by renewable energy (solar, wind), resulting in zero-carbon fuel. Contrasts with grey hydrogen (from fossil fuels) and blue hydrogen (fossil fuels + carbon capture). India's National Green Hydrogen Mission aims to make India a global hub for production and export.

Data Protection Board of India is an independent regulatory body established under DPDP Act 2023 to enforce provisions, adjudicate disputes, and impose penalties. CERT-In handles cybersecurity incidents; RBI regulates financial data; TRAI oversees telecom. Understanding regulatory roles is key for governance questions.

Minimum nodes occur in a skewed tree (each node has only one child): height h has h+1 nodes. Maximum nodes in a perfect binary tree of height h is 2^(h+1)-1. Understanding tree properties is essential for algorithm analysis questions in technical government exams.

kill sends signals to processes; default is SIGTERM (15) which requests graceful termination, allowing cleanup. SIGKILL (9) forces immediate termination but doesn't allow cleanup. Processes can ignore or handle signals. Understanding process signals is important for system administration questions.

Lithium-ion batteries offer high energy density, long cycle life, and declining costs, making them ideal for residential solar storage. Lead-acid is cheaper but heavier with shorter lifespan. Flow batteries suit grid-scale storage. India's PLI scheme promotes domestic Li-ion cell manufacturing for energy transition.

DPDP Act 2023 establishes framework for processing digital personal data, defining rights of data principals and obligations of data fiduciaries. Replaces Section 43A of IT Act 2000. Aligns with global standards while addressing India-specific needs. Critical for compliance questions in banking and UPSC exams.

Preorder traversal: Root → Left Subtree → Right Subtree. Inorder: Left → Root → Right (gives sorted order for BST). Postorder: Left → Right → Root. Level-order uses queue for breadth-first traversal. Tree traversals are frequently tested in SSC JE and programming exams.