Delhi Police HC AWO/TPO cheat sheet

Delhi's administrative units: 11 districts, 3 statutory municipal corporations merged into MCD (2022), and the Delhi Cantonment Board; the Lieutenant Governor is the constitutional head, the Chief Minister heads the elected government.

Delhi is a Union Territory with a Legislative Assembly (70 seats) under Article 239AA; it has no separate High Court of its own - the Delhi High Court (est. 1966) exercises jurisdiction.

Key Delhi landmarks and dates: Red Fort and Jama Masjid (Shah Jahan, 17th century), Qutub Minar (started by Qutb-ud-din Aibak, 1193), India Gate (1921, designed by Edwin Lutyens), Rashtrapati Bhavan (formerly Viceroy's House).

Delhi's historic cities: seven cities including Mehrauli, Siri, Tughlaqabad, Jahanpanah, Firozabad, Shergarh (Purana Qila) and Shahjahanabad; the Iron Pillar at Mehrauli dates to the Gupta period.

Delhi institutions: Indian Parliament (Sansad Bhavan), Supreme Court, NITI Aayog, RBI central office, National Museum, IGI Airport (Indira Gandhi International), and the Delhi Metro (operational since 2002).

Delhi-specific bodies: Delhi Development Authority (DDA, 1957), Delhi Jal Board, Delhi Transport Corporation (DTC), Delhi Police (headed by Commissioner of Police), and the Delhi Disaster Management Authority.

Current-affairs framing: track appointments (President, Chief Justice of India, RBI Governor, Delhi Police Commissioner), recent schemes, sports events, and awards - questions usually test who/what/where, not analysis.

Static-plus-current linkage: match a current event to its state/country/capital or to a constitutional article; e.g., new schemes are usually launched under a named ministry, not the state government.

Series rule check: for number series, compute first and second differences; if second differences are constant it is quadratic, if ratios are constant it is geometric, if alternating it is two interleaved series.

Alphabet positions: A=1 … Z=26; reverse position = 27 − forward position. Opposite-letter pairs are A-Z, B-Y, C-X, D-W, E-V, F-U, G-T, H-S, I-R, J-Q, K-P, L-O, M-N.

Coding-decoding: test shift (+n/−n), reversal, position-sum, and letter-pair substitution in that order; a consistent shift across all letters confirms a Caesar-type code.

Blood relations: draw a family tree with gender markers; never infer gender from a name or a relationship word like 'cousin' or 'child'.

Direction sense: use a coordinate grid, north = +y, east = +x; final displacement = √(x² + y²); left/right turns depend on current facing direction, not on the page.

Syllogism: apply Venn diagrams; a conclusion follows only if it is true in every possible diagram consistent with the premises. 'Some A are B' does not imply 'Some B are not A'.

Seating arrangement: fix the circular table with facing-centre/facing-outside rules - facing centre means left is clockwise; facing outside means left is anticlockwise.

Analogy and classification: identify the relation type (part-whole, cause-effect, worker-tool, synonym/antonym, unit-measure) before choosing the option; reject options matching only surface similarity.

Percentage change: successive changes of a% and b% give net change = a + b + ab/100. A 20% increase followed by a 20% decrease yields a net 4% decrease.

Profit and loss: SP = CP × (100 + P%)/100; when two articles are sold at the same price with equal gain% and loss%, there is always a net loss of (x²/100)%.

Simple and compound interest: SI = PRT/100; CI = P[(1 + R/100)^T − 1]; for 2 years the CI − SI difference equals P(R/100)².

Time, speed and distance: average speed for equal distances = 2xy/(x + y), not (x + y)/2. Trains: time to cross a platform = (train length + platform length)/speed.

Work and pipes: combined rate = sum of individual rates; if A does work in x days and B in y days, together they take xy/(x + y) days. A leak subtracts from filling rate.

Ratio and mixture: alligation rule - ratio of quantities = (mean − cheaper) : (dearer − mean). Repeated replacement reduces pure quantity by P(1 − x/V)^n.

Mensuration: circle area πr², circumference 2πr; sphere volume 4/3πr³, surface 4πr²; cylinder volume πr²h, curved surface 2πrh; cone volume 1/3πr²h.

Averages and ages: new average after adding a value = (old total + value)/(n + 1); if every item is increased by k, the average increases by k and the variance is unchanged.

Number system shortcuts: divisibility by 3 and 9 by digit sum, by 11 by alternating digit sum, by 8 by last three digits; LCM × HCF = product of the two numbers.

Subject-verb agreement: 'one of the + plural noun' takes a singular verb; 'each, every, either, neither, nobody' are singular; 'none' may be singular or plural depending on the noun it refers to.

Articles: 'a' before consonant sounds, 'an' before vowel sounds (an hour, a university, an MLA); 'the' with superlatives, rivers, ranges, and unique objects.

Prepositions: 'discuss' and 'reach' take no preposition; 'comprise' takes no 'of'; 'superior, inferior, senior, junior, prefer' take 'to', not 'than'.

Tenses: 'since' and 'for' pair with perfect tenses; 'when' with past simple pairs with past continuous for the interrupted action; conditionals use 'If + past perfect, would have + past participle'.

Voice and narration: passive = object + be + past participle + by + subject; in reported speech, present becomes past, 'this' becomes 'that', and 'today' becomes 'that day' when the reporting verb is past.

Common confusions: affect (verb) vs effect (noun); principal (head/main) vs principle (rule); stationary (still) vs stationery (paper); complement (completes) vs compliment (praise).

Idioms tested in police/administrative papers: 'to turn a deaf ear' (ignore), 'to be in hot water' (in trouble), 'to bury the hatchet' (make peace), 'a bolt from the blue' (sudden shock), 'to burn the midnight oil' (work late).

Comprehension strategy: locate the topic sentence, answer only from the passage, and reject options with extreme words ('always', 'never', 'all') unless the passage states them verbatim.

संधि: स्वर संधि (दो स्वर मिलने पर), व्यंजन संधि (व्यंजन + स्वर/व्यंजन), विसर्ग संधि। उदाहरण - विद्या + आलय = विद्यालय (दीर्घ संधि), नर + इंद्र = नरेंद्र (गुण संधि)।

समास के भेद: तत्पुरुष (अंत में लिंग/विभक्ति), कर्मधारय (विशेषण-विशेष्य), द्वंद्व (दोनों पद प्रधान), बहुव्रीहि (अन्य पद प्रधान), द्विगु (संख्यावाची), अव्ययीभाव (पूर्व पद अव्यय)।

उपसर्ग और प्रत्यय: 'अनु' + 'शासन' = अनुशासन; 'लिख' + 'आवट' = लिखावट। प्रत्यय दो प्रकार के - कृत् (क्रिया से) और तद्धित (संज्ञा/विशेषण से)।

वाक्य शुद्धि: 'सभी लड़के आए हैं' सही, 'सभी लड़के आया है' अशुद्ध; कर्ता बहुवचन हो तो क्रिया बहुवचन में आएगी। 'कृपया' के साथ 'आग्रह' का प्रयोग करें, आदेशार्थक रूप नहीं।

मुहावरे: 'आँख का तारा' (बहुत प्यारा), 'नौ दो ग्यारह होना' (भाग जाना), 'लोहे के चने चबाना' (कठिन काम करना), 'अंधे की लाठी' (एकमात्र सहारा), 'कान भरना' (चुगली करना)।

पर्यायवाची और विलोम: 'सूर्य' - रवि, भानु, दिनकर, आदित्य; 'अंधकार' का विलोम 'प्रकाश'; 'उत्कर्ष' का विलोम 'अपकर्ष'; 'स्वदेश' का विलोम 'विदेश'।

वर्तनी: 'पर्यावरण', 'अनुसंधान', 'विशेषज्ञ', 'उपर्युक्त' शुद्ध रूप हैं; 'क्ष', 'त्र', 'ज्ञ' संयुक्त व्यंजन हैं और इनकी गणना एक अक्षर के रूप में होती है।

गद्यांश समझ: मुख्य विचार पहले वाक्य में खोजें, प्रश्न का उत्तर केवल अनुच्छेद से दें, और अति सामान्य या अति विशिष्ट विकल्पों को हटाएँ।

Radio spectrum bands used in police wireless: HF 3–30 MHz (long-distance, skywave), VHF 30–300 MHz (line-of-sight, handheld/mobile sets), UHF 300 MHz–3 GHz (short range, building penetration).

Modulation: AM varies carrier amplitude (long range, noise-prone), FM varies carrier frequency (noise-resistant, used in VHF police sets), and digital modes (e.g., APCO P25, DMR) encode voice as bits for encryption and clarity.

Propagation: ground wave follows the earth's surface at LF/MF; skywave reflects off the ionosphere at HF and varies with day/night; space wave is line-of-sight and is why VHF range ≈ 1.23√h km for antenna height h in metres.

Antenna basics: half-wave dipole length ≈ 143/f(MHz) metres; a quarter-wave vertical ≈ 71.5/f(MHz). VSWR near 1:1 is ideal; a high VSWR means mismatch and reflected power.

Receiver/transmitter terms: sensitivity (minimum detectable signal), selectivity (rejection of adjacent channels), bandwidth, squelch (mutes noise when no carrier), CTCSS/DCS (sub-audible tone squelch for shared channels).

Electronic components: resistor limits current (V = IR), capacitor stores charge (Q = CV, blocks DC, passes AC), inductor opposes current change, diode rectifies, transistor amplifies or switches; Ohm's law and Kirchhoff's laws are the base for all circuit questions.

Tele-printer (teletype) operation: a keyboard generates a 5-bit Baudot code; a distributor converts parallel bits to serial for transmission; the receiver's selector decodes and drives the printer; the answer-back drum sends a station identification on interrogation (WRU).

Tele-printer practicals: 50 baud ≈ 66 words per minute (Baudot, 7.5 bits per character); mark = current flowing/idle line, space = no current/active; a loop current of about 20 mA (60 mA in some systems) is standard; faults commonly traced to the loop, the motor governor, or paper/ribbon feed.

Typical Delhi Police HC (AWO/TPO) paper pattern: objective MCQ sections on General Awareness, Reasoning, Numerical Ability, English, Hindi and trade knowledge; negative marking is commonly applied, so skip blind guesses.

Time allocation rule: attempt the section you are strongest in first within its sectional limit; leave a question after 45–60 seconds if no method is visible.

Elimination heuristic: in numerical MCQs, check the unit and approximate magnitude of options before full calculation; in reasoning, verify the chosen option against the stated condition once.

Trade-section priority: radio fundamentals (bands, modulation, propagation) and tele-printer basics carry more weight than deep circuit design; memorise the constants and formulas listed in the trade section.

Revision cycle: static GK and formulas daily, current affairs weekly; keep a single error log and re-attempt only logged errors before the exam.

Delhi Police is headed by the Commissioner of Police and functions under the Union Ministry of Home Affairs; it is divided into ranges and districts, each led by a DCP/Joint CP.

Specialised units include the Crime Branch, Special Cell (counter-terrorism), Traffic Police, PCR (Police Control Room), Economic Offences Wing, and the Security Unit.

Key legal anchors: Bharatiya Nyaya Sanhita (replacing IPC), Bharatiya Nagarik Suraksha Sanhita (replacing CrPC), and Bharatiya Sakshya Adhiniyam (replacing the Evidence Act), effective 1 July 2024.

FIR basics: an FIR records a cognizable offence; a Zero FIR can be filed at any police station regardless of jurisdiction and is later transferred to the competent station.

Fundamental rights relevant to policing: Article 21 (life and personal liberty), Article 22 (protection on arrest - grounds of arrest, lawyer, production before a magistrate within 24 hours), Article 20 (no self-incrimination, no double jeopardy).

Police ranks in ascending order: Constable, Head Constable, Assistant Sub-Inspector, Sub-Inspector, Inspector, ACP, DCP, Joint CP, Special CP, Commissioner of Police.

Community policing initiatives associated with Delhi Police include Yuva, Pratidhi, and the Senior Citizens' Security Scheme; the PCR number is 112 (emergency) and 100 for police.

Binary and digital basics: 1 byte = 8 bits; 1 KB = 1024 bytes; decimal to binary by repeated division by 2; hexadecimal uses 0–9 and A–F, and each hex digit maps to exactly 4 bits.

Logic gates: AND outputs 1 only if all inputs are 1; OR outputs 1 if any input is 1; NOT inverts; NAND and NOR are universal gates; XOR outputs 1 when inputs differ.

MS Word and Excel essentials: Ctrl+C/V/X copy/paste/cut, Ctrl+Z undo, Ctrl+F find; in Excel, =SUM(A1:A5), =AVERAGE(), =IF(condition, true, false), and $ fixes a cell reference absolutely.

Computer networking: IP address identifies a device on a network; LAN is local, WAN spans large areas; a router forwards between networks, a switch within a LAN; HTTP/HTTPS, FTP and SMTP are application-layer protocols.

Data storage and security: RAM is volatile, ROM is non-volatile; antivirus, strong passwords and firewalls are basic safeguards; phishing is a fraudulent attempt to obtain credentials via fake messages.

Indian polity: the Constitution was adopted on 26 November 1949 and came into force on 26 January 1950; the Preamble was amended by the 42nd Amendment (1976), adding 'socialist', 'secular' and 'integrity'.

Fundamental duties were added by the 42nd Amendment on the recommendation of the Swaran Singh Committee; the Right to Education (Article 21A) was added by the 86th Amendment (2002).

Geography: the Tropic of Cancer passes through eight Indian states; the Himalayas are young fold mountains; the Western Ghats are continuous while the Eastern Ghats are discontinuous; the Deccan Trap is basaltic.

Rivers: the Ganga rises at Gangotri (Bhagirathi), the Brahmaputra at Mansarovar (as Tsangpo), and the Indus in Tibet; the Narmada and Tapi flow west into the Arabian Sea.

Science basics: the SI unit of force is the newton, of power the watt, of frequency the hertz; speed of light ≈ 3 × 10^8 m/s; sound travels faster in solids than gases and cannot travel in a vacuum.

Human body: the largest organ is the skin, the smallest bone the stapes, the longest bone the femur; blood groups follow the ABO and Rh systems; vitamin A deficiency causes night blindness, D deficiency rickets.

Awards and firsts useful for GK: Bharat Ratna is India's highest civilian award; the Param Vir Chakra is the highest wartime gallantry award; Delhi hosted the 2010 Commonwealth Games.

Table/bar interpretation: read the title and units first; compute only the requested ratio or difference rather than all totals; percentage share = (part/total) × 100.

Percentage-point vs percent: a change from 40% to 50% is 10 percentage points but a 25% relative increase.

Pie chart: each sector angle = (value/total) × 360°; a 1% share equals 3.6°.

Average-based problems: if the average of n numbers is A, total = nA; when one item is replaced and the average changes by d, the replaced item differs by n × d.

Partnership: profit shares are in the ratio of capital × time; if capitals are equal, shares follow the time ratio.

Boats and streams: downstream speed = boat + stream, upstream = boat − stream; boat speed = (down + up)/2, stream speed = (down − up)/2.

Pipes with leaks: net filling rate = filling rate − leak rate; if a pipe fills in x hours and a leak empties in y hours, net time = xy/(y − x) when y > x.

Standard radio telephony: use the ICAO/Police phonetic alphabet (Alpha, Bravo, Charlie … Zulu) and read digits individually; 'Roger' means received, 'Wilco' means will comply, 'Over' invites a reply, 'Out' ends the exchange.

Call procedure: identify the called station, then the calling station, then the message; keep transmissions short and use plain language rather than codes when clarity matters.

Distress and urgency: 'MAYDAY' (spoken three times) signals grave and imminent danger; 'PAN-PAN' signals urgency without immediate danger; 'SECURITE' precedes safety messages.

Radio discipline: listen before transmitting, use the push-to-talk button fully, never transmit on a channel during a distress call, and log all messages with time and station.

Licensing and compliance: wireless apparatus in India operates under the Indian Wireless Telegraphy Act, 1933 and rules framed under the Telecommunications Act, 2023; unauthorised transmission or jamming is an offence.

Equipment care: check antenna connection before transmitting (transmitting with no antenna can damage the final amplifier), keep batteries charged, and report faults through the prescribed channel.

High-frequency synonyms: abate = lessen, candid = frank, diligent = hardworking, frugal = thrifty, lucid = clear, obsolete = outdated, prudent = wise, tenacious = persistent.

High-frequency antonyms: benevolent × malevolent, transient × permanent, ambiguous × clear, augment × diminish, candid × evasive, hostile × friendly, timid × bold.

One-word substitutions: one who speaks many languages = polyglot; one who loves mankind = philanthropist; a speech made without preparation = extempore; a place where money is coined = mint; that which cannot be avoided = inevitable.

Spelling traps: accommodate, committee, embarrass, harass, occurrence, privilege, recommend, separate, vacuum - double letters are the usual error point.

Fill-in-the-blank rule: check the preposition and verb pattern that the blank governs; 'comprise' takes no 'of', 'consist' takes 'of', 'depend' takes 'on', 'comply' takes 'with'.

संज्ञा के भेद: व्यक्तिवाचक (राम, दिल्ली), जातिवाचक (नगर, नदी), भाववाचक (सुंदरता, बचपन), समूहवाचक (सेना, भीड़), द्रव्यवाचक (सोना, जल)।

सर्वनाम के भेद: पुरुषवाचक (मैं, तुम, वह), निजवाचक (अपना, स्वयं), निश्चयवाचक (यह, वह), अनिश्चयवाचक (कोई, कुछ), प्रश्नवाचक (कौन, क्या), संबंधवाचक (जो, सो), निजवाचक।

क्रिया: सकर्मक क्रिया में कर्म होता है ('राम ने पत्र लिखा'), अकर्मक में नहीं ('बच्चा सोया'); वाच्य तीन प्रकार के - कर्तृवाच्य, कर्मवाच्य, भाववाच्य।

काल: वर्तमान, भूतकाल (सामान्य, पूर्ण, अपूर्ण), भविष्यत्; 'रहा है' अपूर्ण वर्तमान, 'चुका है' पूर्ण वर्तमान दर्शाता है।

अलंकार: अनुप्रास (वर्णों की आवृत्ति), उपमा ('चरण कमल के समान'), रूपक (अभेद आरोप), यमक (एक शब्द का भिन्न अर्थ में दोहराव), श्लेष (एक शब्द के अनेक अर्थ)।

रस के नौ भेद: शृंगार, हास्य, करुण, रौद्र, वीर, भयानक, बीभत्स, अद्भुत, शांत; शांत रस को रसराज कहा जाता है।

Mirror image: the mirror is placed vertically, so left and right swap and top/bottom stay the same; water image swaps top and bottom and keeps left/right unchanged.

Paper folding and cutting: unfold in reverse order of folding; each fold doubles the number of holes, so n folds can give up to 2^n holes.

Counting figures: count triangles in a divided triangle by labelling regions and summing combinations of adjacent regions; count squares by size class (1×1, 2×2, …) and add.

Embedded figures and pattern completion: compare only the outline and internal lines, not shading or rotation; rotation is allowed, distortion is not.

Cubes and dice: a standard die has opposite faces summing to 7; in a painted cube cut into n³ small cubes, corner cubes (8) have 3 painted faces, edge cubes 12(n − 2) have 2, face cubes 6(n − 2)² have 1.

Statement and assumption: an assumption is unstated but necessary for the statement; reject options that merely restate the statement or add extra information.

Cause and effect: decide which event precedes and can produce the other; if both are effects of a common cause, the answer is that neither is the cause.

Electricity: V = IR (Ohm's law), P = VI = I²R = V²/R; in series, current is the same and resistance adds; in parallel, voltage is the same and 1/R adds reciprocally.

Household wiring: live wire (red/brown), neutral (black/blue), earth (green); a fuse or MCB protects against overload by breaking the circuit; earthing prevents shock from leakage.

Batteries: a lead-acid cell has about 2 V per cell, a lithium-ion cell about 3.6–3.7 V; capacity is rated in ampere-hours (Ah); connecting cells in series adds voltage, in parallel adds capacity.

Sound and light: audible range for humans is 20 Hz to 20 kHz; ultrasound is above 20 kHz; light travels in straight lines and reflects at an angle equal to the angle of incidence.

Everyday science: a pressure cooker raises boiling point by increasing pressure; a refrigerator works by evaporation and condensation of a refrigerant; optical fibre works on total internal reflection.

Track flagship central schemes by ministry: Ayushman Bharat (Health), PM-KISAN (Agriculture), Jal Jeevan Mission (Jal Shakti), PM Vishwakarma (MSME), and Skill India (Skill Development).

Constitutional and institutional heads: the President is the head of state, the Chief Justice of India heads the judiciary, the RBI Governor heads monetary policy, and the Comptroller and Auditor General audits government accounts.

International groupings to know: BRICS, G20, SCO, QUAD, ASEAN, and the UN and its principal organs (General Assembly, Security Council, ICJ, Secretariat).

Sports: the Olympics are held every four years; the Commonwealth Games likewise; India's national game commonly cited is hockey; the Ranji Trophy is for cricket and the Santosh Trophy for football.

Awards: Bharat Ratna, Padma Vibhushan, Padma Bhushan, Padma Shri in descending order; the Nobel Prize is announced annually in October; the Booker Prize is for fiction in English.

Defence and security current affairs: track new inductions (aircraft, missiles), exercises, and appointments such as the Chief of Defence Staff and service chiefs.

Spot-the-error order: check subject-verb agreement, then tense consistency, then pronoun reference, then prepositions/articles, then word order.

Parallelism: items joined by 'and', 'or', 'not only … but also' must have the same grammatical form; 'not only … but also' also requires inverted word order in formal style.

Modifiers: a participial phrase must modify the subject of the main clause; 'Walking down the road, I saw a dog' is correct, 'Walking down the road, a dog was seen by me' is dangling.

Countable vs uncountable: 'much/little' with uncountables (much water, less traffic), 'many/few' with countables (many books, fewer seats); 'less' vs 'fewer' is a frequent trap.

Conditional and subjunctive: after 'wish' and 'as if', use 'were' for all persons; after 'if' in unreal conditions, use past or past perfect, never 'would' in the if-clause.

Redundancy: avoid 'return back', 'discuss about', 'repeat again', 'more better', 'very unique' - these are the standard error-spotting traps.

Relative speed: same direction = difference of speeds; opposite direction = sum of speeds.

Train crossing a pole: time = length of train/speed; crossing a platform or bridge: time = (train + platform length)/speed.

Two trains crossing each other: time = (L1 + L2)/(relative speed); convert km/h to m/s by multiplying by 5/18.

Upstream/downstream and escalator problems use the same relative-motion structure: net speed = object speed ± medium speed.

Circular track: time to meet again = circumference/relative speed; if they start together and meet at the start, the time is the LCM of their individual lap times.

Average speed with two speeds over equal distances = harmonic mean 2xy/(x + y); over equal times it is the arithmetic mean.

No paper feed: check the platen, the paper-release lever, and the feed rollers; a jammed ribbon often mimics a paper fault.

Garbled print: suspect the loop current, the Baudot code timing, or the distributor/selector alignment; test with the local loop first.

No answer-back: the answer-back drum may be out of position or the WRU interrogation circuit open; the drum sends station identity only when interrogated.

Motor runs but no print: check the clutch, the selector magnets, and the range-finder setting; a mis-set range finder produces distorted characters.

Transmitter faults: no carrier usually means the final amplifier, antenna connection, or power supply; check VSWR and the antenna before replacing modules.

Battery/loop supply: teleprinters commonly use a 20 mA or 60 mA loop; a break in the loop stops all printing even if the motor runs.

Ranking: if a person is nth from the left and mth from the right, total = n + m − 1; if only one side is given, the total is the sum of positions minus one only when both are given.

Overlapping sets: use n(A ∪ B) = n(A) + n(B) − n(A ∩ B); for three sets subtract pairwise intersections and add back the triple intersection.

Floor puzzles: draw a vertical ladder with numbered floors and place clues from the most restrictive to the least; fix absolute positions before relative ones.

Scheduling puzzles: build a day/time grid and mark 'definitely' and 'definitely not'; a clue like 'A is before B but after C' fixes the order C, A, B.

Blood-relation puzzles with generations: assign generation numbers (+1, 0, −1) and check that a parent is exactly one generation above a child.

Coding by position: for word codes, note whether letters are reversed, shifted, or substituted by their opposite letter (A↔Z); test one word fully before applying the rule.

Delhi's civic structure changed in 2022 when the three municipal corporations (North, South, East) were reunified into a single Municipal Corporation of Delhi.

Delhi's air-quality management is coordinated by the Commission for Air Quality Management (CAQM) in NCR and adjoining areas, which orders GRAP restrictions based on AQI thresholds.

Delhi transport initiatives include the Delhi Metro network expansion, the electric-vehicle policy, and the odd-even vehicle rationing scheme used during pollution episodes.

Delhi Police public interfaces: the 112 emergency response system, the Himmat app for women's safety, and the Delhi Police website for online complaints and verification.

Delhi's heritage and tourism: Qutub Minar and Humayun's Tomb are UNESCO World Heritage Sites; the Lotus Temple, Akshardham, and Rajghat are major visitor sites.

Delhi's political calendar: the Legislative Assembly has 70 seats; elections are normally held every five years; the Lieutenant Governor is appointed by the President.

Series types to test in order: constant difference, constant ratio, difference of differences, alternating two-series, prime numbers, squares/cubes, and n² ± k patterns.

Approximation: round to the nearest convenient value (e.g., 49.8 × 20.2 ≈ 50 × 20 = 1000) and choose the closest option; do not compute exactly when options are far apart.

Simplification order: BODMAS - brackets, orders (powers/roots), division/multiplication left to right, then addition/subtraction left to right.

Surds and indices: a^m × a^n = a^(m+n); a^m/a^n = a^(m−n); (a^m)^n = a^(mn); √a × √b = √(ab).

Percentage-fraction equivalents: 1/8 = 12.5%, 1/6 ≈ 16.67%, 1/3 ≈ 33.33%, 3/8 = 37.5%, 5/8 = 62.5%, 7/8 = 87.5% - memorise these to speed up simplification.

Squares to 30 and cubes to 15 are worth memorising; they appear directly in series and simplification questions.

Inference questions: the answer must be logically supported but not directly stated; reject options that are true in general but not supported by the passage.

Tone and purpose questions: identify whether the author is critical, neutral, optimistic, or analytical by looking at adjectives and qualifiers, not just the topic.

Vocabulary in context: replace the word with each option and check whether the sentence still makes sense; the common meaning may not be the passage meaning.

Main idea: it is usually broader than any single paragraph and narrower than the general topic; a good main-idea option covers all paragraphs.

Fact vs opinion: a fact can be verified, an opinion expresses judgement; questions asking 'which is stated' require a direct textual match.

Para-jumbles: find the opening sentence (usually general, no pronouns referring back), then link sentences by pronouns, conjunctions, and repeated nouns.

Ancient India: the Indus Valley Civilisation (Harappa, Mohenjo-daro) is known for town planning and drainage; the Mauryan Empire under Ashoka spread Buddhism; the Gupta period is called the Golden Age.

Medieval India: the Delhi Sultanate had five dynasties (Slave, Khilji, Tughlaq, Sayyid, Lodi); the Mughal Empire was founded by Babur after the First Battle of Panipat (1526).

The 1857 revolt began at Meerut and is called the First War of Independence; the Indian National Congress was founded in 1885 and the Muslim League in 1906.

Freedom movement milestones: Jallianwala Bagh (1919), Non-Cooperation (1920), Dandi March (1930), Quit India (1942), and Independence on 15 August 1947.

Culture: classical dances are Bharatanatyam (Tamil Nadu), Kathak (North India), Kathakali (Kerala), Odissi (Odisha), Kuchipudi (Andhra Pradesh), Manipuri, Mohiniyattam, and Sattriya.

Classical languages and literature: Sanskrit, Tamil, Telugu, Kannada, Malayalam, and Odia have classical status; the Vedas are the oldest Indian texts.

RBI functions: issues currency, controls monetary policy, acts as banker to the government and to banks, manages foreign exchange, and regulates the banking system.

Monetary tools: repo rate (RBI lends to banks), reverse repo (RBI borrows), CRR (cash reserve ratio), SLR (statutory liquidity ratio), and open market operations.

Inflation measures: CPI (consumer price index) and WPI (wholesale price index); the RBI's inflation target is 4% with a band of ±2%.

Banking terms: NPA (non-performing asset), KYC (know your customer), CASA (current and savings accounts), and priority sector lending targets.

Government finances: the Union Budget is presented annually; fiscal deficit is total expenditure minus total receipts excluding borrowings; GST is a destination-based indirect tax.

Categorical propositions: 'All A are B' converts to 'Some B are A'; 'No A is B' converts to 'No B is A'; 'Some A are B' converts to 'Some B are A'.

Possibility in syllogisms: a conclusion is possible if there exists at least one valid diagram satisfying the premises; 'can be true' is weaker than 'must be true'.

Input-output and machine puzzles: track the transformation rule (sorting, shifting, arithmetic) across steps and apply it to the target step rather than solving all steps.

Decision-making questions: choose the option that follows the stated rule or policy, not personal preference; the correct answer usually applies the rule literally.

Analytical reasoning with conditions: list all constraints, then test each option against every constraint; eliminate options that violate any one condition.

Number and letter analogy: identify the operation (multiply by n, add n, reverse, square) on the first pair and apply the same operation to the second.

गद्यांश हल करने का क्रम: शीर्षक और पहला वाक्य पढ़ें, फिर प्रश्न पढ़ें, फिर अनुच्छेद में उत्तर खोजें; उत्तर अनुच्छेद के शब्दों के आधार पर दें।

औपचारिक पत्र के अंग: प्रेषक का पता, दिनांक, प्राप्तकर्ता का पता, विषय, संबोधन, मुख्य भाग, समापन और हस्ताक्षर; विषय पत्र के मध्य में लिखा जाता है।

अनौपचारिक पत्र में संबंध के अनुसार संबोधन होता है ('प्रिय मित्र', 'आदरणीय पिताजी'); औपचारिक पत्र में 'महोदय/महोदया' का प्रयोग होता है।

निबंध लेखन: भूमिका, विषय-विस्तार, और उपसंहार - तीन भागों में लिखें; अनावश्यक पुनरावृत्ति से बचें और तकनीकी शब्दों का सही प्रयोग करें।

वाक्य-शुद्धि में सामान्य त्रुटियाँ: लिंग-वचन का अनमेल, अनावश्यक पुनरुक्ति ('वापस लौट आया'), और गलत संधि-विच्छेद।

मुहावरों का वाक्य में प्रयोग करते समय उनका अर्थ स्पष्ट रखें; मुहावरे का शाब्दिक अर्थ नहीं, लाक्षणिक अर्थ लिया जाता है।

Frequency and wavelength: λ (metres) = 300/f (MHz); a 100 MHz signal has a 3 m wavelength; a half-wave dipole at that frequency is about 1.5 m.

Bandwidth and information: wider bandwidth supports higher data rates; FM broadcast uses about 200 kHz per channel, AM about 10 kHz, and narrowband VHF voice about 12.5–25 kHz.

Transmission line: characteristic impedance of a coaxial cable is typically 50 Ω (radio) or 75 Ω (video); matching to the antenna minimises reflection and maximises power transfer.

Standing wave ratio (VSWR): 1:1 is perfect; 1.5:1 is acceptable; above 2:1 indicates a mismatch that can damage the transmitter.

Signal-to-noise ratio: a higher SNR means clearer reception; noise figure measures how much a receiver degrades SNR; sensitivity is the weakest signal a receiver can use.

Duplex operation: simplex uses one frequency alternately, half-duplex uses two frequencies but one direction at a time, full-duplex allows simultaneous two-way communication.

Phrasal verbs with 'put': put off (postpone), put up with (tolerate), put down (suppress/insult), put forward (propose), put out (extinguish).

Phrasal verbs with 'take': take after (resemble), take over (assume control), take in (deceive/understand), take up (begin a hobby), take off (depart/succeed).

Common idioms: 'at the drop of a hat' (immediately), 'once in a blue moon' (rarely), 'to let the cat out of the bag' (reveal a secret), 'to beat around the bush' (avoid the main point).

Prepositional phrases: 'in lieu of' (instead of), 'by virtue of' (because of), 'in the wake of' (following), 'on the verge of' (about to), 'at the helm of' (in charge of).

Confusable pairs: 'bring up' (raise a child) vs 'bring about' (cause); 'look after' (care for) vs 'look into' (investigate); 'turn down' (reject) vs 'turn up' (arrive).

Triangle: sum of angles = 180°; area = ½ × base × height; Heron's formula area = √[s(s−a)(s−b)(s−c)] with s = (a+b+c)/2; Pythagoras applies only to right triangles.

Circle: chord, tangent and secant theorems - tangent is perpendicular to the radius at the point of contact; angle in a semicircle is 90°; angle at the centre is twice the angle at the circumference.

Quadrilaterals: area of trapezium = ½(a + b)h; parallelogram = base × height; rhombus = ½ × d1 × d2; sum of interior angles of an n-sided polygon = (n − 2) × 180°.

Trigonometric values: sin 30° = ½, sin 45° = 1/√2, sin 60° = √3/2; cos and tan follow from the standard right triangle; tan θ = sin θ/cos θ.

Heights and distances: angle of elevation is measured upward from the horizontal, angle of depression downward; use tan θ = height/distance for the standard problems.

Coordinate geometry: distance = √[(x2−x1)² + (y2−y1)²]; midpoint = ((x1+x2)/2, (y1+y2)/2); slope = (y2−y1)/(x2−x1).

Environment: the Kyoto Protocol (1997) and Paris Agreement (2015) address climate change; the Montreal Protocol protects the ozone layer; the Ramsar Convention protects wetlands.

Indian environmental bodies: the Central Pollution Control Board, the National Green Tribunal (2010), and the Ministry of Environment, Forest and Climate Change.

Sports cups: Ranji Trophy and Duleep Trophy (cricket), Santosh Trophy (football), Agha Khan Cup (hockey), Thomas Cup (badminton men), Davis Cup (tennis).

National symbols: the tiger is the national animal, the peacock the national bird, the lotus the national flower, and the Ganga the national river.

Important days: 26 January (Republic Day), 15 August (Independence Day), 5 September (Teachers' Day), 2 October (Gandhi Jayanti), 26 November (Constitution Day).

First in India: first President Dr Rajendra Prasad, first Prime Minister Jawaharlal Nehru, first woman Prime Minister Indira Gandhi, first Indian Nobel laureate Rabindranath Tagore.

Odd-one-out: identify the shared property (all are metals, all are capitals, all are tools) and pick the option that breaks it; the odd item often differs in category, not in spelling.

Word-pair relations: worker and workplace (doctor–hospital), tool and user (stethoscope–doctor), cause and effect (rain–flood), and part and whole (wheel–car).

Letter-series with gaps: write the alphabet with positions and compute differences; if differences alternate, split into two series at odd and even positions.

Number-letter mixed series: treat letters by position and numbers separately; the rule often alternates between the two streams.

Dictionary order: compare letter by letter from the left; a shorter word precedes a longer word sharing the same prefix.

Jumbled words: look for common suffixes (-tion, -ment, -ing) and prefixes (un-, re-, pre-) to anchor the rearrangement.

संधि-विच्छेद के उदाहरण: सूर्य + उदय = सूर्योदय (गुण), देव + इंद्र = देवेंद्र (गुण), हिम + आलय = हिमालय (दीर्घ), वाक् + ईश = वागीश (व्यंजन)।

समास-विग्रह: राजपुत्र = राजा का पुत्र (तत्पुरुष), नीलकमल = नीला है जो कमल (कर्मधारय), माता-पिता = माता और पिता (द्वंद्व), चौराहा = चार राहों का समूह (द्विगु)।

शब्द-शक्ति: अभिधा (शब्द का सीधा अर्थ), लक्षणा (लाक्षणिक अर्थ), व्यंजना (सूचित अर्थ); 'गंगा में मगरमच्छ हैं' में लक्षणा का प्रयोग होता है।

विलोम शब्द: अमृत × विष, उत्थान × पतन, संयोग × वियोग, स्वदेश × विदेश, आदि × अंत, ज्ञान × अज्ञान।

अनेकार्थी शब्द: 'कनक' का अर्थ सोना और धतूरा; 'हरि' का अर्थ विष्णु, इंद्र, सूर्य और बंदर; 'गुरु' का अर्थ शिक्षक और बड़ा।

वाक्य के भेद अर्थ के आधार पर: विधानवाचक, निषेधवाचक, प्रश्नवाचक, आज्ञावाचक, विस्मयादिबोधक, संदेहवाचक, इच्छावाचक।

Police wireless networks typically use VHF/UHF trunked or conventional systems; VHF is preferred for wide-area mobile coverage, UHF for handheld use inside buildings.

Repeater stations extend range by receiving on one frequency and retransmitting on another; the 'offset' is the frequency difference between input and output.

Control room (PCR) communication: the dispatcher assigns callsigns, monitors channels, and relays messages; field units acknowledge with the callsign and a brief 'received'.

Encryption and privacy: digital systems support end-to-end encryption; analogue systems can be monitored, so sensitive information is passed by secure means or coded.

Emergency power: wireless stations are backed by UPS/battery banks; a common fault during power failure is a discharged battery, not a radio fault.

Interference: co-channel interference comes from another transmitter on the same frequency; adjacent-channel interference from a nearby frequency; both are reduced by proper filtering and channel spacing.

Data sufficiency method: test each statement alone first, then both together; stop as soon as sufficiency is established and never compute the actual answer unless needed.

Statement sufficiency: a statement is sufficient if it gives a unique value; if it gives two possible values, it is insufficient.

Approximation with fractions: compare fractions by cross-multiplication (a/b vs c/d: compare ad and bc) rather than converting to decimals.

Square roots: √(a²) = a for positive a; approximate √n by finding the nearest perfect squares and interpolating; √2 ≈ 1.414, √3 ≈ 1.732, √5 ≈ 2.236.

Percentage of a percentage: x% of y% of z = (x × y × z)/10000; use this for compound percentage questions.

Ratio comparison: to divide an amount in the ratio a:b:c, the shares are A × a/(a+b+c), A × b/(a+b+c), A × c/(a+b+c).

Formal letter structure: sender's address, date, receiver's address, subject line, salutation, body in three paragraphs, closing, and signature; the subject line states the purpose in one line.

Notice and report writing: a notice includes the heading 'NOTICE', the issuing authority, date, and a body of 50 words; a report includes what, when, where, who, and outcome.

Precis writing: retain the central idea, cut examples and repetition, and keep it to about one-third of the original length without adding opinion.

Instruction comprehension: identify the sequence of steps and the condition attached to each step; questions usually ask what happens if a step is skipped or a condition fails.

Email etiquette: a clear subject, a greeting, short paragraphs, a specific request, and a professional sign-off; avoid slang and all-caps.

Delhi Police traces its modern structure to the Delhi Police Act; it is a Union Territory police force under the administrative control of the Ministry of Home Affairs.

The Commissioner of Police is appointed by the central government; the force assists in law and order, traffic, VIP security, and crime investigation in Delhi.

The Police Control Room (PCR) vans patrol the city and respond to calls on 112; the number 100 is the traditional police helpline.

Specialised Delhi Police units include the Crime Branch, Special Cell, Economic Offences Wing, Traffic Police, and the Security Division.

Community initiatives: Yuva (youth engagement), Pratidhi (women's self-defence), and the Senior Citizens' Security Scheme for the elderly.

Delhi Police has been associated with major operations including counter-terrorism duties and crowd management during national events on Republic Day.

Symbol substitution: replace each symbol with the given operation, then apply BODMAS strictly; do not evaluate left to right unless only addition and subtraction remain.

Interchange problems: when two numbers or signs are interchanged, rewrite the whole expression before evaluating; a common trap is interchanging only one occurrence.

Inequality with symbols: 'A > B ≥ C' implies A > C; 'A < B ≤ C' implies A < C; combining a strict and a non-strict inequality keeps the strict relation.

Mathematical operations with missing numbers: balance both sides by treating the unknown as a variable and solving the resulting linear equation.

Coded operations: if 'P + Q' means P is the father of Q, build the family tree with the code table before answering relationship questions.

Matrix and arrangement codes: read rows and columns as coordinates; a code like (2,3) means row 2, column 3 of the given grid.

कार्यालयीन पत्राचार में प्रयुक्त शब्द: 'प्रेषक' (भेजने वाला), 'प्राप्तकर्ता', 'संलग्न' (attach), 'अनुलग्नक', 'प्रतिलिपि' (copy), 'क्रमांक' (number), 'दिनांक'।

सरकारी हिंदी में अंग्रेजी शब्दों के पर्याय: file = संचिका, draft = प्रारूप, office = कार्यालय, register = पंजी, receipt = रसीद, circular = परिपत्र, memo = ज्ञापन।

पारिभाषिक शब्दावली: computer = संगणक, telephone = दूरभाष, radio = रेडियो/आकाशवाणी, message = संदेश, signal = संकेत, frequency = आवृत्ति, transmitter = प्रेषित्र, receiver = ग्राही।

टिप्पणी लेखन: संक्षिप्त, तथ्यपूर्ण और निर्णय-केंद्रित होनी चाहिए; विकल्प सुझाना और अंत में अनुमोदन के लिए स्थान छोड़ना आवश्यक है।

सरकारी पत्र का प्रारूप: क्रमांक, दिनांक, सेवा में (प्राप्तकर्ता), विषय, महोदय, मुख्य पाठ, भवदीय, हस्ताक्षर एवं पदनाम।

हिंदी में संख्याओं और मात्रकों का प्रयोग: 'किलोमीटर', 'मेगाहर्ट्ज़', 'वाट', 'वोल्ट' जैसे तकनीकी शब्द देवनागरी में वैसे ही लिखे जाते हैं।

Electromagnetic spectrum order by increasing frequency: radio, microwave, infrared, visible, ultraviolet, X-ray, gamma; radio waves have the longest wavelength.

Radio wave speed in free space = 3 × 10^8 m/s; wavelength and frequency are inversely related by λ = c/f.

Modulation types: amplitude modulation (AM), frequency modulation (FM), phase modulation (PM); FM has better noise immunity because noise mostly affects amplitude.

Signal sampling: the Nyquist theorem states the sampling rate must be at least twice the highest frequency to reconstruct the signal.

Antenna gain is measured in dBi or dBd; a 3 dB gain doubles the power in the preferred direction; dB = 10 log10(P1/P2) for power ratios.

Noise sources: thermal noise (increases with temperature and bandwidth), shot noise, and interference; a lower noise figure improves receiver sensitivity.

Prefixes: un-, in-, dis-, non- negate; re- means again; pre- means before; post- means after; sub- means under; trans- means across.

Suffixes: -able/-ible (capable of), -tion/-sion (noun form), -ous (full of), -ify (make), -ment (state or result), -less (without).

Word families: 'analyse' (verb), 'analysis' (noun), 'analytical' (adjective), 'analytically' (adverb); questions often test the correct form in a sentence.

Collocations: 'make a decision', 'take a decision' (British), 'do a favour', 'give an order', 'pay attention', 'keep a promise' - verb-noun pairing is tested in fill-in-the-blanks.

Formal vs informal: 'commence' vs 'start', 'terminate' vs 'end', 'request' vs 'ask for', 'assist' vs 'help'; formal register is expected in official writing.

Ratio and proportion: if a:b = c:d, then ad = bc; if a:b = b:c, b is the mean proportional and b² = ac.

Compound ratio: the compound ratio of a:b and c:d is ac:bd; duplicate ratio of a:b is a²:b²; sub-duplicate is a:b's square roots.

Partnership: profit share = capital × time; if A invests for 12 months and B for 6 months with equal capital, the ratio is 12:6 = 2:1.

Mixture replacement: after n replacements of x litres from V litres of pure liquid, the pure quantity is V(1 − x/V)^n.

Ages: if the present ages are in ratio a:b and after t years in ratio c:d, set up (ax + t)/(bx + t) = c/d and solve for x.

Proportion in work: if m1 men do w1 work in d1 days and m2 men do w2 work in d2 days, then m1d1/w1 = m2d2/w2 when hours per day are equal.

पर्यायवाची: 'पृथ्वी' - धरती, भूमि, वसुधा, धरा; 'जल' - पानी, नीर, वारि, अंबु; 'पर्वत' - गिरि, शैल, अचल, नग।

विलोम: 'अनुराग' × विराग, 'उत्साह' × निरुत्साह, 'कृतज्ञ' × कृतघ्न, 'सज्जन' × दुर्जन, 'स्वतंत्र' × परतंत्र।

अनेक शब्दों के लिए एक शब्द: जिसकी कोई तुलना न हो - अनुपम; जो कहा न जा सके - अकथनीय; जिसका आदि न हो - अनादि; जो सब कुछ जानता हो - सर्वज्ञ; जो इंद्रियों को वश में रखे - जितेंद्रिय।

शब्द-युग्म: 'अवधि' (समय) और 'अवधी' (भाषा); 'आदि' (प्रारंभ) और 'आधि' (मानसिक पीड़ा); 'दिन' और 'दीन'; 'प्रसाद' और 'प्रासाद' - अर्थ भिन्न हैं।

वर्तनी शुद्धि: 'अनुग्रह', 'आशीर्वाद', 'क्रमशः', 'पुनरावृत्ति', 'प्रतिदिन', 'विशेषज्ञ' - इनका शुद्ध रूप याद रखें।

Multimeter use: measure voltage in parallel with the load, current in series, and resistance with the circuit unpowered; selecting the wrong mode can damage the meter.

Oscilloscope: displays voltage against time; the time-base control sets the horizontal scale and the volts/div control sets the vertical scale; use it to check modulation and waveform shape.

Frequency counter: counts cycles per second; accuracy depends on the time-base crystal; used to verify transmitter frequency and offset.

SWR meter: connected between transmitter and antenna to measure forward and reflected power; a high reflected reading indicates antenna mismatch or cable damage.

Signal generator: produces test tones for aligning receivers and checking audio stages; the output level is set in microvolts or dBm.

Soldering practice: use rosin-core solder, tin the iron before use, heat the joint and apply solder to the joint not the iron, and avoid cold joints which cause intermittent faults.

Read the units and the base year before computing; a common error is comparing absolute numbers with percentages.

Percentage increase = (new − old)/old × 100; percentage decrease uses the same formula with a negative numerator.

Ratio of two rows: simplify by dividing both by their HCF; the answer is often asked as a ratio in lowest terms.

Average of a column = sum of entries/number of entries; if the average and n are given, the sum is n × average.

Maximum/minimum questions: scan the table for the largest and smallest values; do not compute all differences unless the question asks for the largest change.

Pie chart to table conversion: value = (angle/360) × total; percentage = (angle/360) × 100.

National days: 15 January (Army Day), 8 October (Air Force Day), 4 December (Navy Day), 30 January (Martyrs' Day), 14 November (Children's Day).

International days: 8 March (Women's Day), 22 April (Earth Day), 5 June (Environment Day), 21 June (Yoga Day), 10 October (Mental Health Day).

Freedom fighters: Bhagat Singh, Sukhdev and Rajguru were executed on 23 March 1931; Subhas Chandra Bose led the Azad Hind Fauj; Sardar Patel integrated the princely states.

Scientists: C.V. Raman (Raman effect), Homi Bhabha (nuclear programme), Vikram Sarabhai (space programme), A.P.J. Abdul Kalam (missile programme and President).

Sports personalities: Major Dhyan Chand (hockey), Sachin Tendulkar (cricket), P.T. Usha (athletics), Mary Kom (boxing), and Abhinav Bindra (first individual Olympic gold for India, 2008).

Present perfect vs past simple: 'I have finished' relates to now; 'I finished' states a completed past action with a definite time.

Past perfect is used for the earlier of two past actions: 'He had left before I arrived.'

Passive voice formation: object becomes subject, verb becomes be + past participle, and the original subject becomes 'by + agent' or is dropped.

Reported speech changes: present to past, 'will' to 'would', 'can' to 'could', 'may' to 'might', 'must' to 'had to'; time words shift (now → then, tomorrow → the next day).

Reported questions use statement order: 'He asked where I was going', not 'He asked where was I going'.

Conditionals: zero (present + present), first (present + will), second (past + would), third (past perfect + would have + past participle).

स्वर संधि के पाँच भेद: दीर्घ (अ+अ = आ), गुण (अ+इ = ए), वृद्धि (अ+ए = ऐ), यण (इ+अ = य), अयादि (ए+अ = अय)।

व्यंजन संधि: 'सत् + जन = सज्जन', 'उत् + हार = उद्धार', 'जगत् + नाथ = जगन्नाथ' - व्यंजन के बाद स्वर या व्यंजन आने पर परिवर्तन होता है।

विसर्ग संधि: 'निः + चय = निश्चय', 'दुः + ख = दुःख', 'मनः + रथ = मनोरथ' - विसर्ग का 'श', 'ष', 'स' या 'ओ' में परिवर्तन।

उपसर्ग के उदाहरण: 'अनु' (अनुकरण), 'अप' (अपमान), 'प्र' (प्रगति), 'वि' (विज्ञान), 'सु' (सुगम), 'नि' (निराशा), 'परा' (पराजय)।

प्रत्यय के उदाहरण: 'लड़कपन' (पन), 'मिठास' (आस), 'बुढ़ापा' (आपा), 'सुनार' (आर), 'लेखक' (अक), 'सुंदरता' (ता)।

संधि-विच्छेद करते समय पहले स्वरों की पहचान करें; यदि दोनों स्वर मिलकर दीर्घ बनें तो दीर्घ संधि, यदि गुण स्वर बने तो गुण संधि।

Baudot code is a 5-bit code giving 32 combinations; figures and letters share the same codes and are switched by FIGS and LTRS shift characters.

Control characters: CR (carriage return), LF (line feed), BEL (bell), NUL (blank), and WRU (who are you, triggers answer-back).

Speed: 45.45 baud (60 wpm) and 50 baud (66 wpm) are common teleprinter speeds; the character rate is baud/7.5 approximately.

Message format: precedence (emergency, operational, routine), call sign, text, and signature; messages are logged with time of receipt and dispatch.

Punched tape: 5-hole paper tape carries one character per row; a parity hole may be added; tape is read by a mechanical or optical reader.

Security: messages of a sensitive nature are encrypted or sent by secure means; the answer-back identifies the station and prevents misrouting.

Statement and conclusion: a conclusion must follow from the statement alone, not from general knowledge; reject options that require outside information.

Course of action: a valid action must be practical, address the problem directly, and be within the authority of the body mentioned.

Cause and effect: if two statements are given, decide whether one causes the other or both share a common cause; the answer 'both are effects' is common.

Assumption: the assumption must be necessary for the statement to make sense; a sufficient but unnecessary condition is not an assumption.

Strengthening and weakening: a strengthening statement makes the conclusion more likely; a weakening statement introduces an alternative cause or a counterexample.

Inference: it is a conclusion drawn from the given facts; it must be definitely true, not merely probable.

Percentage of a number: x% of N = (x/100) × N; to increase N by x%, multiply by (1 + x/100).

Reverse percentage: if a number increased by x% becomes N, the original = N × 100/(100 + x).

Average of consecutive numbers = (first + last)/2; for n consecutive integers starting at a, the average is a + (n − 1)/2.

Weighted average = (w1x1 + w2x2)/(w1 + w2); the result always lies between the two values.

Ages: if the present age is x, then t years ago it was x − t and after t years it will be x + t; set up equations from the given ratio conditions.

Population growth: after n years at r% per annum, population = P(1 + r/100)^n; for depreciation use (1 − r/100)^n.

Technical passages: identify the process described and the sequence of steps; questions often ask what happens first, next, or as a result.

Cause-effect markers: 'because', 'therefore', 'as a result', 'consequently', 'owing to' signal the logical relation tested in inference questions.

Contrast markers: 'however', 'although', 'nevertheless', 'on the other hand' signal a shift; the answer often lies in the contrast, not the main clause.

Definition questions: the passage usually defines a term in the same sentence or the next; match the definition to the option with the same scope.

Numerical data in passages: check units and whether the figure is a total, a rate, or a percentage before selecting an option.

Author's purpose in technical writing: usually to explain, instruct, or compare; 'to criticise' is rare unless evaluative adjectives appear.

Article 14: equality before law; Article 19: six freedoms including speech and expression; Article 21: life and personal liberty; Article 32: right to constitutional remedies (called the heart and soul of the Constitution by Ambedkar).

Article 44: uniform civil code (directive principle); Article 40: organisation of village panchayats; Article 48A: protection of environment.

Article 356: President's rule in a state; Article 352: national emergency; Article 360: financial emergency.

Amendment procedure: Article 368 provides for amendment by simple majority, special majority, or special majority plus ratification by half the states.

Important amendments: 42nd (1976, mini-Constitution), 44th (1978, property right removed from fundamental rights), 73rd and 74th (panchayats and municipalities), 101st (GST), 103rd (EWS reservation).

Emergency provisions: national emergency (Article 352), state emergency (Article 356), financial emergency (Article 360); fundamental rights except Articles 20 and 21 can be suspended during a national emergency.

मुहावरे: 'अंधेर नगरी चौपट राजा' (बिना विवेक का शासन), 'एक और एक ग्यारह होना' (संगठन में शक्ति), 'नाच न जाने आँगन टेढ़ा' (अपनी अक्षमता छिपाना), 'थोथा चना बाजे घना' (दिखावा अधिक)।

लोकोक्ति और मुहावरे में अंतर: मुहावरा वाक्यांश है जो क्रिया के रूप में प्रयुक्त होता है; लोकोक्ति पूर्ण वाक्य है जो अनुभव पर आधारित कहावत है।

मुहावरे का वाक्य प्रयोग: 'उसने परीक्षा में प्रथम आकर अपने माता-पिता का मान बढ़ाया' - 'मान बढ़ाना' मुहावरे का अर्थ प्रतिष्ठा बढ़ाना है।

शब्दों का लिंग: 'नदी' स्त्रीलिंग, 'पर्वत' पुल्लिंग, 'किताब' स्त्रीलिंग, 'विद्यालय' पुल्लिंग; लिंग के अनुसार विशेषण और क्रिया का रूप बदलता है।

वचन: 'लड़का' से 'लड़के', 'किताब' से 'किताबें'; कुछ शब्दों में केवल वचन बदलता है और लिंग नहीं।

Rectifier converts AC to DC; an inverter converts DC to AC; a UPS combines a rectifier, battery, and inverter to supply uninterrupted power.

Lead-acid battery: 2 V per cell, 6 cells for 12 V; specific gravity of the electrolyte indicates charge state (about 1.28 when fully charged).

Battery capacity in Ah: a 100 Ah battery can supply 5 A for 20 hours ideally; higher discharge rates reduce effective capacity.

Charging: constant-current then constant-voltage (CC-CV) is standard for lithium-ion; overcharging a lead-acid battery causes gassing and water loss.

Earthing and protection: the station earth must have low resistance; fuses and MCBs protect against short circuits; a reverse-polarity connection can destroy the radio's final stage.

Solar backup: a solar panel rating in watts divided by system voltage gives charging current; a charge controller prevents overcharge and reverse flow.

Letter shift coding: compute the shift between the first letters of the word and its code; if the shift is constant, apply it to the target word.

Reverse coding: the code may be the word written backwards, or letters replaced by their opposite letters (A↔Z, B↔Y).

Number coding: the code may be the sum of letter positions, the product of the first and last positions, or the position of the first letter followed by the length.

Mixed alphanumeric series: treat letters and numbers as two streams; the rule often alternates between them.

Symbol substitution series: replace symbols with numbers and look for the arithmetic pattern in the resulting series.

Conditional coding: read the conditions in order and apply the first matching condition; questions test whether you follow priority correctly.

Vitamins: A (vision, deficiency causes night blindness), B1 (beriberi), B12 (anaemia), C (scurvy), D (rickets), K (clotting).

Diseases: malaria (Plasmodium, mosquito), dengue (virus, Aedes mosquito), tuberculosis (bacteria, air), cholera (bacteria, water), polio (virus, vaccine).

Blood: red blood cells carry oxygen using haemoglobin; white blood cells fight infection; platelets help clotting; the normal human blood pH is about 7.4.

First aid: for burns, cool with running water; for fractures, immobilise the limb; for snake bite, keep the patient calm and immobilise, do not cut or suck the wound.

Nutrition: carbohydrates and fats provide energy, proteins build tissue, vitamins and minerals regulate body functions, and water is essential for metabolism.

Active to passive: identify the object, make it the subject, use the correct form of 'be' plus past participle, and keep the tense unchanged.

Passive to active: the agent after 'by' becomes the subject; if no agent is given, use 'someone' or 'people' as the subject.

Imperative sentences in passive: 'Open the door' becomes 'Let the door be opened'; 'Do not touch the wire' becomes 'Let the wire not be touched'.

Interrogative sentences in passive: 'Did he write the letter?' becomes 'Was the letter written by him?' - the auxiliary moves to the front.

Direct to indirect: remove quotation marks, change the reporting verb to 'said that' or 'told', shift the tense back, and change pronouns according to the speaker-listener relation.

Indirect to direct: restore quotation marks, change the reporting verb to 'said', and shift the tense forward if the reporting verb is in the past.

रेडियो एवं संचार के पारिभाषिक शब्द: transmitter = प्रेषित्र, receiver = ग्राही, antenna = एंटीना/वायुसंचारी, frequency = आवृत्ति, modulation = मॉडुलन, signal = संकेत, wavelength = तरंगदैर्घ्य।

टेलीप्रिंटर से संबंधित शब्द: teleprinter = दूरमुद्रक, keyboard = कुंजीपटल, tape = फीता, code = कूट, message = संदेश, circuit = परिपथ, current = धारा।

विद्युत के शब्द: voltage = वोल्टता, current = धारा, resistance = प्रतिरोध, power = शक्ति, battery = संचायक/बैटरी, circuit = परिपथ, conductor = चालक।

कार्यालयीन शब्द: register = पंजी, file = संचिका, dispatch = प्रेषण, receipt = रसीद, report = प्रतिवेदन, order = आदेश, circular = परिपत्र।

तकनीकी हिंदी में संक्षिप्ताक्षर: 'आर.एफ.' (रेडियो आवृत्ति), 'वी.एच.एफ.' (अति उच्च आवृत्ति), 'यू.एच.एफ.' (अति उच्चतर आवृत्ति), 'एस.डब्ल्यू.आर.' (स्थायी तरंग अनुपात)।