Class 10 Science Model Paper 2026
Max Marks: 80 | Time: 3 Hours
- Section A: Biology (Q1-16)
- Section B: Chemistry (Q17-29)
- Section C: Physics (Q30-39)
Section A: Biology
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2nd Trophic Level = Herbivores (Primary Consumers).
3rd Trophic Level = Carnivores (Secondary Consumers).
Reason (R): Humans occupy the top level in any food chain, so the maximum concentration of these chemicals gets accumulated in our bodies.
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Reason (R): Males have one X and one Y chromosome.
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Reason (R): Villi increase the surface area for absorption of digested food.
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Aquatic organisms utilize oxygen dissolved in water. Since the amount of dissolved oxygen is fairly low compared to the amount of oxygen in the air, the rate of breathing in aquatic organisms is much faster to absorb sufficient oxygen.
A. How does the chemical coordination take place in animals?
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Answer A: Chemical coordination is maintained by hormones secreted by endocrine glands. These hormones are released directly into the blood and reach specific target organs (sites) to regulate physiological functions (growth, metabolism, etc.).
Answer B: At the synapse, the electrical impulse reaches the axonal end of one neuron and releases chemicals called neurotransmitters. These chemicals cross the gap (synapse) and start a similar electrical impulse in the dendrite of the next neuron.
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- Segregation: Separating biodegradable (wet waste) and non-biodegradable (dry waste) at the source so they can be treated separately.
- Composting: Converting biodegradable kitchen waste into manure (compost) which reduces the volume of garbage and enriches the soil.
(i) Elongation of cells
(ii) Promoting cell division
(iii) Inhibiting growth
(b) What is a reflex arc? Draw a schematic flow chart of it.
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(a) Hormones:
(i) Auxin
(ii) Cytokinins
(iii) Abscisic Acid
(b) Reflex Arc: The pathway taken by nerve impulses in a reflex action is called a reflex arc.
Flow Chart:
Stimulus $\rightarrow$ Receptor (Skin) $\rightarrow$ Sensory Neuron $\rightarrow$ Spinal Cord (Relay Neuron) $\rightarrow$ Motor Neuron $\rightarrow$ Effector (Muscle) $\rightarrow$ Response.
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| Inherited Traits | Acquired Traits |
|---|---|
| Traits passed from parents to offspring via genes (DNA). | Traits developed during the lifetime due to environment or practice. |
| These can be passed to the next generation. | These cannot be passed to the next generation. |
| Ex: Eye colour, Skin colour. | Ex: Swimming skills, cut on a finger. |
Case Study: Reproductive health is the state of physical, mental, and social well-being in all matters relating to the reproductive system. To maintain this, family planning and contraception are essential. A couple visited a doctor to understand methods to prevent unwanted pregnancies.
Attempt either subpart A or B.
A. (i) Name one mechanical barrier method of contraception. What is its additional benefit?
(ii) How do oral contraceptive pills function to prevent pregnancy?
B. (i) Name the surgical methods of contraception in males and females respectively.
(ii) A woman uses a Copper-T loop. Will it protect her from Sexually Transmitted Diseases (STDs)? Justify.
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Answer A:
(i) Condoms. Additional Benefit: They prevent the transmission of Sexually Transmitted Diseases (STDs) like HIV/AIDS and Syphilis.
(ii) Oral pills contain hormones (estrogen/progesterone) which prevent the release of eggs (ovulation) from the ovary. Without an egg, fertilization cannot occur.
Answer B:
(i) Male: Vasectomy. Female: Tubectomy.
(ii) No. Copper-T prevents pregnancy by preventing implantation, but it does not provide a barrier against fluid exchange. Therefore, it cannot prevent STDs.
A. (i) Draw a well-labelled diagram of the human excretory system.
(ii) Explain the function of the Nephron.
(iii) What is the difference between excretion in plants and animals?
(ii) What is the role of the tube nucleus in the pollen tube?
(iii) Name the parts of the flower that develop into (a) Seed and (b) Fruit after fertilization.
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Answer for A:
(i) (Student must draw Kidneys, Ureters, Bladder, Urethra).
(ii) Nephron: It filters the blood. The Bowman's capsule collects filtrate (glucose, amino acids, salts, water). Useful substances are reabsorbed in the tubular part, and waste (urea) remains as urine.
(iii) Animals have specialized organs (kidneys), while plants excrete waste through falling leaves, bark, or secreting gums/resins.
Answer for B:
(i) Transfer of pollen from anther to stigma. Self: Same flower/plant. Cross: Different plant.
(ii) Tube nucleus controls the growth of the pollen tube towards the ovary.
(iii) (a) Seed: Ovule, (b) Fruit: Ovary.
Section B: Chemistry
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Reason (R): Decomposition of Silver Chloride in presence of sunlight takes place to form Silver metal and Chlorine gas.
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(i) What is the colour of the precipitate formed?
(ii) Name the compound precipitated and write the balanced chemical equation.
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(i) Colour: Yellow Precipitate.
(ii) Compound: Lead Iodide ($PbI_2$).
Equation:
$Pb(NO_3)_2(aq) + 2KI(aq) \rightarrow PbI_2(s) + 2KNO_3(aq)$
A. Differentiate between Roasting and Calcination with one example of each.
(ii) Why do covalent compounds usually have low melting and boiling points?
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Answer A:
1. Roasting: Heating sulphide ores in excess air. (e.g., $2ZnS + 3O_2 \rightarrow 2ZnO + 2SO_2$).
2. Calcination: Heating carbonate ores in limited/no air. (e.g., $ZnCO_3 \rightarrow ZnO + CO_2$).
Answer B:
(i) $N_2$: Triple bond between two N atoms ($:N \equiv N:$).
$CH_4$: Carbon in center sharing 1 electron each with 4 Hydrogens.
(ii) Covalent compounds have weak intermolecular forces of attraction, so less energy is required to break the bonds between molecules.
(ii) Mention one practical application of this reaction.
(iii) Why are ionic compounds usually hard solids?
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(i) Thermite Reaction: The reaction of Iron(III) oxide with Aluminium powder is highly exothermic and produces molten iron.
$Fe_2O_3(s) + 2Al(s) \rightarrow 2Fe(l) + Al_2O_3(s) + Heat$
(ii) Application: Used to join railway tracks or cracked machine parts.
(iii) Hardness: Due to the strong force of attraction between the positive and negative ions in the crystal lattice.
Case Study: Plaster of Paris (POP) is a white powder. When it is mixed with water, it sets into a hard solid mass due to the formation of Gypsum. This property makes it very useful in the medical field for setting fractured bones in the right position.
Attempt the following questions:
A. Write the chemical name and formula of Plaster of Paris.
B. Write the balanced chemical equation for the reaction of Plaster of Paris with water.
Attempt either subpart C or D.
C. Why should Plaster of Paris be stored in a moisture-proof container?
D. How is Plaster of Paris prepared? Write the reaction temperature required.
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Answer A:
Chemical Name: Calcium Sulphate Hemihydrate.
Formula: $CaSO_4 \cdot \frac{1}{2}H_2O$.
Answer B (Equation):
$CaSO_4 \cdot \frac{1}{2}H_2O + 1\frac{1}{2}H_2O \rightarrow CaSO_4 \cdot 2H_2O$ (Gypsum).
Answer C:
It should be stored in moisture-proof containers because it absorbs moisture from the atmosphere and hardens into Gypsum, becoming useless.
Answer D (OR):
It is prepared by heating Gypsum ($CaSO_4 \cdot 2H_2O$) at 373 K (100°C) carefully so that it loses 1.5 molecules of water.
A. A neutral organic compound 'X' of molecular formula $C_2H_6O$ on oxidation with alkaline $KMnO_4$ gives an acidic compound 'Y'. Compound 'X' reacts with 'Y' on warming in the presence of Conc. $H_2SO_4$ to give a sweet-smelling substance 'Z'.
(i) Identify X, Y, and Z.
(ii) Write the chemical equations for all reactions involved.
(ii) Differentiate between Soaps and Detergents based on their chemical composition and action in hard water.
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Answer A:
(i) X: Ethanol ($C_2H_5OH$), Y: Ethanoic Acid ($CH_3COOH$), Z: Ethyl Ethanoate (Ester).
(ii) Oxidation: $CH_3CH_2OH \xrightarrow{Alk. KMnO_4} CH_3COOH$
Esterification: $C_2H_5OH + CH_3COOH \xrightarrow{H^+} CH_3COOC_2H_5 + H_2O$
Answer B:
(i) Isomers: Compounds with same formula but different structures. (Draw n-Butane and Iso-butane).
(ii) Soaps: Sodium salts of fatty acids. Do NOT work in hard water (form scum).
Detergents: Ammonium/Sulphonate salts. Work well in hard water.
Section C: Physics
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Reason (R): The magnetic field inside a solenoid is uniform at all points.
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Given: $u = -10$ cm, $f = +15$ cm (Convex mirror).
Formula: $\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$
$\frac{1}{v} = \frac{1}{f} - \frac{1}{u} = \frac{1}{15} - \frac{1}{-10}$
$\frac{1}{v} = \frac{1}{15} + \frac{1}{10} = \frac{2+3}{30} = \frac{5}{30} = \frac{1}{6}$
$v = +6$ cm.
Nature: Since $v$ is positive, the image is formed behind the mirror. It is Virtual and Erect.
A. Calculate the cost of operating a heater of 500 W for 20 hours at the rate of ₹ 6.00 per unit.
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Answer A:
Energy = Power $\times$ Time = $500 W \times 20 h = 10,000 Wh = 10 kWh$.
1 Unit = 1 kWh.
Cost = $10 \times 6 = ₹ 60$.
Answer B:
Heat produced in a resistor is:
1. Directly proportional to square of current ($I^2$).
2. Directly proportional to resistance ($R$).
3. Directly proportional to time ($t$).
Formula: $H = I^2Rt$
(ii) Why does the sky appear dark instead of blue to an astronaut?
(iii) What is the function of the Iris in the human eye?
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(i) At sunrise, sunlight travels a longer distance through the atmosphere. Blue light scatters away, leaving mainly red light (longer wavelength) to reach our eyes.
(ii) At high altitudes (space), there is no atmosphere to scatter light. Since no scattering occurs, the sky appears black/dark.
(iii) The Iris controls the size of the pupil and thereby regulates the amount of light entering the eye.
(i) Calculate the total resistance of the circuit.
(ii) Calculate the total current flowing in the circuit.
(iii) Calculate the current flowing through the $30 \Omega$ resistor.
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(i) Total Resistance ($R_p$):
$\frac{1}{R_p} = \frac{1}{5} + \frac{1}{10} + \frac{1}{30} = \frac{6+3+1}{30} = \frac{10}{30} = \frac{1}{3}$.
$R_p = 3 \Omega$.
(ii) Total Current ($I$):
$I = \frac{V}{R_p} = \frac{6}{3} = 2 A$.
(iii) Current through $30 \Omega$ ($I_3$):
Since it's parallel, Voltage is same (6V).
$I_3 = \frac{V}{R_3} = \frac{6}{30} = 0.2 A$.
(i) List the factors on which the magnitude of force experienced by the conductor depends.
(ii) Under what condition is the force experienced by the conductor maximum?
(iii) State the rule used to find the direction of this force.
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(i) Factors:
- Strength of magnetic field ($B$).
- Strength of electric current ($I$).
- Length of conductor ($L$).
(ii) Maximum Force: When the direction of current is perpendicular ($90^\circ$) to the direction of the magnetic field.
(iii) Rule: Fleming's Left-Hand Rule.
Case Study: Domestic Electric Circuits
In our homes, we receive electric power supply through a main supply (mains). One of the wires has a red insulation cover and is called the Live wire, and the other has black insulation and is called the Neutral wire. The potential difference between the two is 220V. A third wire with green insulation is used for safety.
Answer the following questions:
A. What is the function of the Earth wire (green insulation)?
B. Why is an electric fuse an important component of all domestic circuits?
Attempt either subpart C or D.
C. Two lamps, one rated 100W at 220V and the other 60W at 220V, are connected in parallel to the electric mains supply. What current is drawn from the line if the supply voltage is 220V?
D. Why are copper and aluminium wires usually employed for electricity transmission? Explain why heating elements (like in toasters) are made of an alloy (nichrome) rather than pure metal.
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Answer A: It provides a low-resistance path for the current. If there is any leakage of current to the metallic body of an appliance, it flows to the earth, protecting the user from electric shock.
Answer B: A fuse breaks the circuit if the current exceeds a safe limit (due to short-circuit or overloading), thus preventing fire and damage to appliances.
Answer C:
Total Power $P = P_1 + P_2 = 100 + 60 = 160 W$.
Current $I = \frac{P}{V} = \frac{160}{220} = \frac{8}{11} \approx 0.73 A$.
Answer D (OR):
1. Copper/Aluminium have very low resistivity, so they conduct electricity without much energy loss.
2. Alloys (Nichrome) have higher resistivity and do not oxidize (burn) easily at high temperatures, making them ideal for heating elements.
(ii) Draw a circuit diagram to verify Ohm's law (must include Ammeter, Voltmeter, Rheostat, Battery, Resistor).
(iii) A student plots V vs I graph. What does the slope of this graph represent?
(iv) If the voltage across a bulb is 220V and current is 0.5A, find its power and resistance.
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(i) Ohm's Law: Potential difference (V) across the ends of a conductor is directly proportional to the current (I) flowing through it, provided temperature remains constant ($V = IR$).
(ii) Diagram: (Student to draw circuit with Voltmeter in parallel and Ammeter in series).
(iii) Slope: The slope of V-I graph represents Resistance (R).
(iv) Calculation:
$P = V \times I = 220 \times 0.5 = 110 W$.
$R = V / I = 220 / 0.5 = 440 \Omega$.