Haryana Police Constable cheat sheet
Haryana Police Constable · Keep the key ideas within reach.
General Awareness and Reasoning
Number series: check differences first, then ratios, then alternating (two interleaved) patterns before assuming a square/cube rule.
Odd-one-out in letter clusters: convert letters to positions (A=1 … Z=26); most clusters share a constant gap, the odd one breaks it.
Blood relations: draw a small family tree with gender symbols; never infer gender from a name or a role such as 'doctor'.
Direction sense: fix North up, plot each turn as a vector, and compute final displacement with Pythagoras if turns are at right angles.
Syllogism: a conclusion follows only if it is true in every possible Venn diagram of the premises; 'some A are B' does not imply 'some B are A' is false - it is true.
Coding-decoding: test shift (+n/-n), reversal, and position-based rules (letter value ± digit) in that order.
Ranking: if a person is nth from left and mth from right, total = n + m − 1.
Calendar: a normal year shifts the weekday by 1 day, a leap year by 2; 100 years shift by 5, 400 years by 0.
Statement-assumption and cause-effect items: reject options that add information absent from the statement.
Mathematics / Quantitative Aptitude
Average = sum / count; if every value is increased by k, the average increases by exactly k.
Percentage change: successive changes of a% and b% give a net change of a + b + ab/100 percent.
Profit and loss: SP = CP × (100 + profit%)/100; discount is always calculated on marked price, profit on cost price.
Simple interest = P × R × T / 100; compound interest = P[(1 + R/100)^T − 1]; for 2 years CI − SI = P(R/100)².
Speed: km/h × 5/18 = m/s; for a train of length L crossing a platform of length P, time = (L + P)/speed.
Boats: downstream speed = boat + stream, upstream = boat − stream; boat speed = (down + up)/2.
Work: if A alone takes a days and B alone b days, together they take ab/(a + b) days.
Mensuration: circle area πr², circumference 2πr; sphere volume 4/3πr³, surface 4πr²; cylinder volume πr²h.
Mixtures: alligation gives ratio of quantities = (mean price − cheaper) : (dearer − mean price).
General Science
SI units: force newton, pressure pascal, work/energy joule, power watt, frequency hertz, electric charge coulomb.
Newton's laws: F = ma; every action has an equal and opposite reaction; a body stays at rest or in uniform motion without net force.
Ohm's law V = IR; resistors in series add, in parallel 1/R = 1/R₁ + 1/R₂; household wiring uses parallel connection.
Light: convex lens converges (used to correct hypermetropia), concave lens diverges (corrects myopia); sound cannot travel through vacuum.
pH below 7 is acidic, 7 neutral, above 7 basic; litmus turns red in acid and blue in base.
Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ in the presence of chlorophyll and sunlight; occurs in chloroplasts.
Human body: the largest gland is the liver, the smallest bone the stapes, the longest bone the femur; normal adult pulse ~72 beats/min.
Blood groups: O negative is the universal donor for red cells, AB positive the universal recipient.
Deficiency diseases: vitamin A night blindness, vitamin C scurvy, vitamin D rickets, iron anaemia, iodine goitre.
Computer Knowledge and Basics
1 byte = 8 bits; 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB, 1 TB = 1024 GB.
RAM is volatile working memory; ROM is non-volatile; cache sits between CPU and RAM and is fastest.
Shortcuts: Ctrl+C copy, Ctrl+X cut, Ctrl+V paste, Ctrl+Z undo, Ctrl+Y redo, Ctrl+S save, Ctrl+P print, Alt+F4 close window.
IP addresses: IPv4 is 32-bit dotted decimal, IPv6 is 128-bit; HTTP default port 80, HTTPS 443, FTP 21, SMTP 25.
File extensions: .docx Word, .xlsx Excel, .pptx PowerPoint, .exe executable, .html web page, .jpg image.
Malware types: virus attaches to files, worm self-replicates over networks, trojan disguises as useful software, ransomware encrypts data.
OSI model has 7 layers; TCP/IP model has 4; TCP is connection-oriented, UDP is connectionless.
Search operators: 'site:' restricts to a domain, quotes force an exact phrase, minus sign excludes a term.
Haryana General Knowledge and Current Affairs
Haryana was carved out of Punjab on 1 November 1966 on the recommendation of the Shah Commission; it shares its capital Chandigarh with Punjab.
Districts: 22; divisions: 6 (Ambala, Gurugram, Hisar, Karnal, Rohtak, Faridabad).
State symbols: animal blackbuck (kala hiran), bird black francolin, tree peepal, flower lotus.
Rivers: Yamuna forms much of the eastern border; Ghaggar, Markanda, Saraswati and Sahibi are seasonal; the Western Yamuna Canal and Bhakra canal system irrigate the state.
Economy: Haryana is a leading producer of wheat, mustard and basmati rice; Gurugram and Manesar form a major automobile and IT hub.
Historic sites: Kurukshetra (Mahabharata battlefield, Brahma Sarovar), Panipat (three battles, 1526, 1556, 1761), Surajkund crafts fair, Sultanpur bird sanctuary.
First state to have electrified all villages (1970) and among the highest per-capita incomes among Indian states.
Current affairs: track appointments of the Chief Minister, Governor, Chief Justice of the Punjab and Haryana High Court, and state schemes announced in the budget.
Hindi Language
वर्णमाला: स्वर 11, व्यंजन 33; 'अ' से 'औ' तक स्वर, 'क' से 'ह' तक व्यंजन।
संधि: स्वर संधि (दो स्वर), व्यंजन संधि, विसर्ग संधि; जैसे विद्या + आलय = विद्यालय (दीर्घ संधि)।
समास: तत्पुरुष (राजपुत्र), द्वंद्व (राजा-रानी), द्विगु (त्रिलोक), बहुव्रीहि (दशानन), अव्ययीभाव (प्रतिदिन)।
उपसर्ग अर्थ बदलते हैं: अनु + शासन = अनुशासन; प्र + हार = प्रहार; अप + मान = अपमान।
प्रत्यय: कृत् (पढ़ना, लिखावट) और तद्धित (मानवता, भारतीय)।
अलंकार: अनुप्रास (वर्ण की आवृत्ति), उपमा (सा, सम), रूपक (अभेद आरोप), यमक (एक शब्द भिन्न अर्थ)।
वाक्य शुद्धि: कर्ता-क्रिया लिंग और वचन में समान होने चाहिए; 'ने' के साथ सकर्मक क्रिया सामान्यतः स्त्रीलिंग एकवचन में।
मुहावरे का अर्थ शब्दशः नहीं लिया जाता; जैसे 'आँख का तारा' = बहुत प्रिय।
English Language
Subject-verb agreement: 'one of the + plural noun' takes a singular verb; 'each, every, neither, either' are singular.
Articles: 'a' before consonant sounds, 'an' before vowel sounds (an hour, a university); 'the' for unique or already specified nouns.
Tenses: 'since/for' with present perfect or perfect continuous; 'ago' with simple past.
Prepositions: 'good at', 'married to', 'composed of', 'comprise' takes no 'of', 'superior to' not 'than'.
Active to passive: object becomes subject, verb becomes be + past participle, agent introduced by 'by'.
Common error pairs: affect (verb) / effect (noun); its (possessive) / it's (it is); principal (head) / principle (rule).
Idioms: 'at the drop of a hat' = immediately; 'once in a blue moon' = very rarely; 'to beat about the bush' = avoid the main point.
Synonyms/antonyms are best judged in context; 'abundant' = plentiful, opposite 'scarce'.