Class 10 Science Complete Notes — Physics, Chemistry, Biology

PHYSICS — Chapter-wise Notes

Chapter 1: Light — Reflection and Refraction

Reflection of Light:

• Angle of incidence = Angle of reflection
• Incident ray, reflected ray, and normal — all in same plane

Spherical Mirrors:

• Concave Mirror: Converging mirror (reflecting surface curves inward)
• Convex Mirror: Diverging mirror (reflecting surface curves outward)

Mirror Formula: 1/f = 1/v + 1/u

Magnification: m = -v/u = h'/h

Sign Convention (New Cartesian):

• All distances measured from pole
• Distances in direction of incident light = positive
• Distances against incident light = negative

Image by Concave Mirror: | Object Position | Image Position | Nature | |---|---|---| | At infinity | At F | Real, inverted, point | | Beyond C | Between F and C | Real, inverted, diminished | | At C | At C | Real, inverted, same size | | Between F and C | Beyond C | Real, inverted, enlarged | | At F | At infinity | Real, inverted, very large | | Between P and F | Behind mirror | Virtual, erect, enlarged |

Convex Mirror: Always forms virtual, erect, diminished image behind mirror. Used in rear-view mirrors.

Refraction:

• Bending of light when it passes from one medium to another
• Snell's Law: n₁ sin θ₁ = n₂ sin θ₂
• Light goes toward normal when entering denser medium

Refractive Index: n = speed of light in vacuum / speed of light in medium = c/v

Lens Formula: 1/f = 1/v - 1/u (note: different from mirror!)

Power of Lens: P = 1/f (focal length in meters); unit = Dioptre (D)

• Convex lens: positive power
• Concave lens: negative power

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Chapter 2: Electricity

Electric Current: I = Q/t (Charge/time); unit = Ampere (A)

Potential Difference: V = W/Q (Work/Charge); unit = Volt (V)

Ohm's Law: V = IR (where R = resistance in Ohms Ω)

Resistance Factors:

• R = ρL/A (ρ = resistivity, L = length, A = cross-section area)
• Resistance increases with length, decreases with area
• Resistivity depends only on material and temperature

Resistors in Series:

• R_total = R₁ + R₂ + R₃
• Same current through all; voltage divides

Resistors in Parallel:

• 1/R_total = 1/R₁ + 1/R₂ + 1/R₃
• Same voltage across all; current divides

Electric Power:

• P = VI = I²R = V²/R
• Unit: Watt (W)

Electric Energy: E = Pt = VIt; Commercial unit = kWh (1 kWh = 3.6×10⁶ J)

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Chapter 3: Magnetic Effects of Current

Magnetic Field: Region where magnetic force acts

Oersted's Discovery: Current-carrying conductor produces magnetic field around it.

Right-Hand Thumb Rule: Thumb points in current direction; curled fingers show magnetic field direction.

Fleming's Left-Hand Rule (Motor): Thumb = motion, Index = field, Middle = current

Fleming's Right-Hand Rule (Generator): Thumb = motion, Index = field, Middle = induced current

Electromagnetic Induction (Faraday's Law): Changing magnetic flux induces EMF

• EMF = -dΦ/dt

Electric Motor: Converts electrical energy to mechanical energy (uses Lorentz force)

Electric Generator: Converts mechanical energy to electrical energy (uses electromagnetic induction)

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CHEMISTRY — Chapter-wise Notes

Chapter 1: Chemical Reactions and Equations

Types of Chemical Reactions:

| Type | Description | Example | |---|---|---| | Combination | A + B → AB | 2Mg + O₂ → 2MgO | | Decomposition | AB → A + B | 2H₂O → 2H₂ + O₂ | | Displacement | A + BC → AC + B | Fe + CuSO₄ → FeSO₄ + Cu | | Double Displacement | AB + CD → AD + CB | NaCl + AgNO₃ → AgCl + NaNO₃ | | Redox | Simultaneous oxidation-reduction | 2Mg + O₂ → 2MgO | | Combustion | Substance + O₂ → heat+CO₂+H₂O | CH₄ + 2O₂ → CO₂ + 2H₂O |

Exothermic: Releases heat (e.g., burning) Endothermic: Absorbs heat (e.g., photosynthesis)

Oxidation: Loss of electrons / gain of oxygen Reduction: Gain of electrons / loss of oxygen OIL RIG: Oxidation Is Loss, Reduction Is Gain

Chapter 2: Acids, Bases, and Salts

Acids: Taste sour, turn blue litmus red, pH < 7

• Strong acids: HCl, H₂SO₄, HNO₃
• Weak acids: CH₃COOH (acetic acid), carbonic acid

Bases: Taste bitter, feel soapy, turn red litmus blue, pH > 7

• Strong bases: NaOH, KOH
• Weak bases: NH₃, Mg(OH)₂

Neutralization: Acid + Base → Salt + Water HCl + NaOH → NaCl + H₂O

pH Scale:

• pH 0-6: Acidic (0 = most acidic)
• pH 7: Neutral
• pH 8-14: Basic (14 = most basic)

Important Salts:

• NaCl (Common salt) — formed from strong acid + strong base → neutral pH 7
• Na₂CO₃ (Washing soda) — used in glass making, laundry
• NaHCO₃ (Baking soda) — used in fire extinguishers, antacid
• CaOCl₂ (Bleaching powder) — used in disinfection

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BIOLOGY — Chapter-wise Notes

Life Processes

Nutrition:

• Autotrophs: Make own food (plants via photosynthesis)
• Heterotrophs: Depend on others for food (animals)

Photosynthesis: 6CO₂ + 6H₂O + light → C₆H₁₂O₆ + 6O₂

Occurs in chloroplasts; chlorophyll absorbs light. Three factors: light, CO₂, water.

Respiration:

• Aerobic: C₆H₁₂O₆ + O₂ → CO₂ + H₂O + 38 ATP (in mitochondria)
• Anaerobic: C₆H₁₂O₆ → C₂H₅OH + CO₂ + 2 ATP (in cytoplasm)

Excretion:

• Kidney: Filters blood → forms urine (urea, water, salts)
• Skin: Sweat (water, salt)
• Lungs: CO₂ and water vapor

Human Heart:

• 4 chambers: 2 atria (upper) + 2 ventricles (lower)
• Right side: deoxygenated blood (from body to lungs)
• Left side: oxygenated blood (from lungs to body)
• Double circulation: pulmonary (heart→lungs→heart) + systemic (heart→body→heart)

Heredity and Evolution

Mendel's Laws:

1. Law of Segregation: Each organism has 2 alleles for each trait; they separate during gamete formation
2. Law of Independent Assortment: Genes for different traits assort independently

Terms:

• Dominant allele: expressed even in one copy (capital letter: T)
• Recessive allele: expressed only in two copies (small letter: t)
• Genotype: actual gene combination (TT, Tt, tt)
• Phenotype: visible trait expressed

Monohybrid Cross (Tt × Tt): Offspring ratio: TT : Tt : tt = 1:2:1 Phenotype ratio: Tall : Short = 3:1

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Solved PYQ Questions

Q1 (2023): An object is placed 10 cm in front of a concave mirror of focal length 15 cm. Find image position. Using 1/f = 1/v + 1/u: f=-15, u=-10 1/(-15) = 1/v + 1/(-10) 1/v = 1/10 - 1/15 = (3-2)/30 = 1/30 v = +30 cm (virtual image, behind mirror)

Q2 (2023): Three resistors 2Ω, 3Ω, 6Ω in parallel. Find equivalent resistance. 1/R = 1/2 + 1/3 + 1/6 = 3/6 + 2/6 + 1/6 = 6/6 = 1 R = 1 Ω

Q3 (2022): What is the role of stomata in plants? Stomata are tiny pores in leaves: (1) gas exchange — CO₂ in, O₂ out during photosynthesis; (2) transpiration — water vapor released; (3) controlled by guard cells which open/close based on water availability.

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Quick Revision Checklist

• Mirror formula: 1/f = 1/v + 1/u
• Lens formula: 1/f = 1/v - 1/u (different sign!)
• Power of lens P = 1/f (diopters)
• Ohm's Law: V=IR; Series: R=R1+R2; Parallel: 1/R=1/R1+1/R2
• 6 types of chemical reactions with examples
• pH: <7 acidic, 7 neutral, >7 basic
• Photosynthesis equation and where it occurs
• Aerobic vs anaerobic respiration: ATP produced
• Mendel's laws and 3:1 ratio in monohybrid cross