Bihar Police SI cheat sheet
Bihar Police SI · Keep the key ideas within reach.
General Knowledge and Current Affairs
Bihar Diwas is observed on 22 March, commemorating the separation of Bihar from Bengal in 1912; the day was first celebrated officially in 2010.
The Bihar Legislative Council (Vidhan Parishad) is a permanent house; one-third of its members retire every two years, and it has 75 members.
Nalanda Mahavihara, a UNESCO World Heritage Site since 2016, was founded in the Gupta period and excavated under Alexander Cunningham's surveys.
Bihar's state animal is the gaur (Indian bison), state bird the house sparrow, state tree the peepal, and state flower the marigold (genda).
The Patna High Court was established in 1916; it is the seat of the state judiciary and its jurisdiction extends over the whole state of Bihar.
Current affairs anchors: RBI monetary policy repo rate decisions, Union Budget presented on 1 February, and the G20 summit hosted by India in 2023.
Kunwar Singh of Jagdishpur led the 1857 revolt in Bihar; the Santhal rebellion (1855) was led by Sidhu and Kanhu Murmu.
Bihar shares borders with Nepal to the north and with West Bengal, Jharkhand, and Uttar Pradesh; it has no international border other than Nepal.
General Studies (History, Geography, Polity, Economy, Science)
Fundamental Rights are in Part III (Articles 12-35); the Right to Constitutional Remedies (Article 32) was called the heart and soul of the Constitution by Dr. B. R. Ambedkar.
The Ganga enters Bihar near Chausa, flows east past Patna, and the Kosi (sorrow of Bihar) joins it near Kursela; the Gandak joins near Hajipur.
Photosynthesis: 6CO2 + 6H2O + light energy gives C6H12O6 + 6O2, occurring in chloroplasts with chlorophyll absorbing mainly red and blue light.
The Preamble was amended by the 42nd Amendment (1976), which added socialist, secular, and integrity; the words were held part of the Constitution in Kesavananda Bharati (1973).
GDP at market prices equals C + I + G + (X - M); real GDP is measured at constant prices, nominal at current prices.
The Mauryan Empire under Chandragupta Maurya (321 BCE) had its capital at Pataliputra; Ashoka's Kalinga war (261 BCE) led to the propagation of dhamma.
Speed of light in vacuum is about 3 x 10^8 m/s; acceleration due to gravity g is about 9.8 m/s^2 near Earth's surface.
The Governor of a state is appointed by the President under Article 155 and holds office during the pleasure of the President (Article 156).
Mathematics / Quantitative Aptitude
Average = sum of observations / number of observations; if every value is increased by k, the average increases by k.
Simple interest = P x R x T / 100; compound interest = P(1 + R/100)^T - P for annual compounding.
Speed = distance / time; to convert km/h to m/s multiply by 5/18, and m/s to km/h multiply by 18/5.
Profit percent = (SP - CP)/CP x 100; successive discounts of a% and b% equal a + b - ab/100 percent.
Work: if A alone takes x days and B alone takes y days, together they take xy/(x + y) days.
Pythagorean triples to memorise: (3,4,5), (5,12,13), (7,24,25), (8,15,17), (9,40,41), and their multiples.
Area formulas: circle = pi r^2, triangle = 1/2 x base x height, trapezium = 1/2 x (sum of parallel sides) x height.
Ratio and mixture: alligation rule gives ratio of quantities = (mean price - cheaper)/(dearer - mean price).
Reasoning and Mental Ability
Coding-decoding: map letter positions A=1 to Z=26; opposite letters sum to 27 (A-Z, B-Y, C-X, and so on).
Blood relations: draw a family tree; vertical line = parent-child, horizontal line = siblings/spouse, and use the question's gender cues.
Direction sense: on a standard map north is up; after turning right from north you face east, and left from east you face north.
Series: check differences, then ratios, then squares/cubes; alternating series often split into two interleaved sequences.
Syllogism: use Venn diagrams; a conclusion follows only if true in every possible diagram consistent with the premises.
Calendar: an ordinary year has 1 odd day, a leap year 2 odd days; 100 years have 5 odd days and 400 years have 0 odd days.
Clock: the minute hand gains 5.5 degrees per minute on the hour hand; hands coincide every 65 5/11 minutes.
Hindi Language
संधि: स्वर संधि में दो स्वर मिलते हैं (विद्या + आलय = विद्यालय); व्यंजन संधि में व्यंजन का परिवर्तन होता है।
समास के भेद: तत्पुरुष (राजपुत्र), द्वंद्व (माता-पिता), बहुव्रीहि (चक्रधर), द्विगु (त्रिलोक), अव्ययीभाव (प्रतिदिन)।
उपसर्ग अर्थ बदलते हैं: अनु + शासन = अनुशासन, अप + मान = अपमान, निर + आशा = निराशा।
प्रत्यय: कृत् प्रत्यय क्रिया से बनते हैं (पढ़ + आई = पढ़ाई), तद्धित प्रत्यय संज्ञा/विशेषण से (मिठाई, लड़कपन)।
वाक्य शुद्धि: 'कृपया' के साथ 'आप' का प्रयोग, और 'सभी लोग' जैसे अनावश्यक पुनरुक्ति से बचें।
मुहावरे: 'अंधे की लाठी' का अर्थ है एकमात्र सहारा; 'नौ-दो ग्यारह होना' का अर्थ है भाग जाना।
रस के नौ भेद हैं: शृंगार, हास्य, करुण, रौद्र, वीर, भयानक, बीभत्स, अद्भुत और शांत।
English Language
Subject-verb agreement: 'one of + plural noun' takes a singular verb (One of the boys is here).
Articles: 'a' before consonant sounds, 'an' before vowel sounds (an hour, a university); 'the' for unique or already-specified nouns.
Tenses: present perfect (has/have + past participle) is used for past actions with present relevance, not with a definite past time marker.
Prepositions: 'since' with a point of time, 'for' with a duration; 'between' for two, 'among' for more than two.
Active to passive: object becomes subject, verb becomes be + past participle, and the doer is placed after 'by'.
Idioms: 'to let the cat out of the bag' means to reveal a secret; 'a blessing in disguise' means an apparent misfortune that turns good.
Common error pairs: 'advice' (noun) vs 'advise' (verb), 'affect' (verb) vs 'effect' (noun), 'lie' (recline) vs 'lay' (place).