CBSE Class 10 Notes — Chapter-wise Revision Notes

Key points

• Fundamental Theorem of Arithmetic: every composite number is a product of primes, unique apart from order.
• HCF = product of smallest powers of common primes; LCM = product of greatest powers of all primes involved.
• For two positive integers, HCF(a,b) × LCM(a,b) = a × b (does not extend directly to three numbers).
• Euclid's division lemma a = bq + r, 0 ≤ r < b, is the basis of the division algorithm for HCF.

Key points

• Degree 1 = linear (1 zero), degree 2 = quadratic (at most 2), degree 3 = cubic (at most 3).
• A zero is a point where the graph cuts or touches the x-axis; touching means two equal zeroes (D = 0).
• For ax² + bx + c: α + β = −b/a and αβ = c/a.
• Quadratic with given zeroes: k[x² − (sum)x + product].

Key points

• A balanced equation obeys conservation of mass: atoms of each element are equal on both sides.
• Combination: two or more reactants give one product (CaO + H₂O → Ca(OH)₂, exothermic).
• Decomposition needs energy — thermal (CaCO₃), electrolytic (water), photolytic (AgBr, AgCl).
• Displacement: a more reactive metal displaces a less reactive one (Fe + CuSO₄ → FeSO₄ + Cu).

Key points

• Acids give H⁺ (as H₃O⁺) in water; bases give OH⁻. Acidic behaviour needs water.
• Acid + metal → salt + H₂ (pop test); acid + carbonate/bicarbonate → salt + water + CO₂ (milky lime water).
• Acid + base → salt + water (neutralisation, exothermic).
• Metal oxides are basic, non-metal oxides acidic; Al₂O₃ and ZnO are amphoteric.

Key points

• The French Revolution (1789) shifted sovereignty from the monarch to the body of citizens; symbols included the tricolour and La Marseillaise.
• The Napoleonic Civil Code (1804) abolished birth privileges, secured property rights and simplified administration — but denied political liberty.
• Liberal nationalism meant government by consent, equality before the law and free markets; voting was limited to propertied men.
• The Zollverein (1834) removed tariff barriers among German states, creating a common economic space.

Key points

• Satyagraha means insistence on truth — a non-violent appeal to the conscience of the oppressor; tested by Gandhi at Champaran (1917, indigo), Kheda (1917, revenue relief) and Ahmedabad (1918, mill workers).
• The Rowlatt Act (1919) allowed detention without trial; Gandhi called a nationwide hartal.
• Jallianwala Bagh (13 April 1919): General Dyer fired on a peaceful gathering in an enclosed ground to 'produce a moral effect'; the reaction turned protest nationwide.
• Khilafat committee (1919, Ali brothers) + Congress at Nagpur (Dec 1920) launched Non-Cooperation — surrender of titles, boycott of schools, courts, councils and foreign cloth.

Key points

• Core definitions and terminology used in Power-sharing
• Standard board-exam question patterns from Power-sharing
• Common mistakes students make in Power-sharing

Key points

• Setting: a lone house on the crest of a low hill overlooking a valley with a field of ripe corn.
• Similes: the raindrops are like 'new coins' (money for the crop); after the hail the field looks 'as if covered with salt'.
• The hail is compared to a plague of locusts — total destruction, 'not a leaf' left.
• Lencho is hardworking, literate and has 'ox-like' faith; his only hope after the loss is help from God.

Key points

• Setting: the sandstone amphitheatre of the Union Buildings, Pretoria — the largest gathering of international leaders on South African soil.
• Two national anthems were sung: whites sang 'Nkosi Sikelel iAfrika' and blacks 'Die Stem' — a symbol of a united, non-racial nation.
• Mandela's oath: never again would this land experience the oppression of one by another.
• He honours the 'African patriots' — Africa's greatest sons and daughters — saying he is the sum of all those who came before him.

Key points

• कबीर निर्गुण भक्ति की ज्ञानाश्रयी शाखा के संत कवि हैं; भाषा 'सधुक्कड़ी' कहलाती है।
• 'साखी' का अर्थ है साक्षी/गवाही — अनुभव से मिली सीख दोहे में कही जाती है।
• मीठी वाणी से 'आपा' (अहंकार) मिटता है और सुनने वाले को भी शीतलता मिलती है।
• ईश्वर कण-कण में है; उसे मंदिर-मस्जिद, काबा-कैलाश में नहीं, अपने भीतर खोजना चाहिए (कस्तूरी-मृग दृष्टांत)।

Key points

• मीरा कृष्ण-भक्ति की माधुर्य/दास्य भाव वाली कवयित्री हैं; भाषा राजस्थानी मिश्रित ब्रज।
• पहले पद में द्रौपदी की लाज, प्रह्लाद की रक्षा, डूबती नाव और हिरण्यकशिपु के नाश के उदाहरण देकर मीरा कहती हैं — जैसे पहले भक्तों की रक्षा की, वैसे मेरी भी करो।
• 'चीर बढ़ायो', 'नरहरि रूप' — पौराणिक संदर्भ हैं; मीरा स्वयं को उसी परंपरा की भक्त मानती हैं।
• दूसरे पद में मीरा श्याम की चाकरी माँगती हैं — बाग लगाना, दर्शन पाना, नाम-स्मरण करना और भक्ति-वैभव पाना उनका वेतन है।

Key points

• A machine is 'intelligent' when it learns from data and improves its decisions, not when it merely follows fixed rules.
• Automation follows pre-written rules (timer-based street light); AI adapts using data (recommendation feed).
• AI ⊃ Machine Learning ⊃ Deep Learning; deep learning uses multi-layer neural networks and needs large data.
• Domains: Data Sciences (tables/numbers), Computer Vision (images/video), NLP (text and speech).

Key points

• Problem Scoping uses the 4Ws: Who is affected, What is the problem (with evidence), Where does it occur, Why is solving it worthwhile.
• The problem statement template: 'Our [who] has the problem of [what] while [where]. An ideal solution would be [why].'
• Data Acquisition = collecting reliable, relevant data: surveys, sensors, cameras, APIs, web scraping, open government datasets.
• Training data teaches the model; testing data checks it on unseen examples — a common split is 80:20.

Key points

• Core definitions and terminology used in Neural Networks
• Standard board-exam question patterns from Neural Networks
• Common mistakes students make in Neural Networks