10th Science Quarterly Exam 2026 Question Paper & Answer Key | Theni District (EM)
Boost your exam preparation with the official Theni District 10th Science Quarterly Exam 2026 Question Paper and Answer Key for English Medium students. This page provides direct access to the actual question paper along with detailed, step-by-step solutions to help you evaluate your performance, understand the marking scheme, and master the important concepts for your upcoming board exams.
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COMMON QUARTERLY EXAMINATION - 2026
1. In a myopic eye, the image of the object is formed:
a) behind the retina b) on the retina c) in front of the retina d) on the blind spot
Explanation: Due to elongation of the eyeball or excessive curvature of the cornea/lens, rays from distant objects converge before reaching the retina.
2. Which of the following is correct?
a) Rate of change of charge is electrical power b) Rate of change of charge is current
c) Rate of change of energy is current d) Rate of change of current is charge
Explanation: Electric current is defined as the rate of flow of electric charges in a conductor ($I = Q / t$).
3. The volume occupied by 4.4 g of CO2 at S.T.P is:
a) 22.4 litre b) 2.24 litre c) 0.24 litre d) 0.1 litre
Explanation: Molar mass of $\text{CO}_2 = 12 + 2(16) = 44\text{ g}$. At S.T.P, $44\text{ g}$ occupies $22.4\text{ L}$. Hence, $4.4\text{ g}$ occupies $(22.4 / 44) \times 4.4 = 2.24\text{ L}$.
4. In the alumino thermic process the role of Al is:
a) oxidizing agent b) reducing agent c) hydrogenating agent d) sulphurising agent
Explanation: Aluminium has a high affinity for oxygen and reduces metal oxides to their corresponding molten metals.
5. Deliquescence is due to:
a) strong affinity to water b) less affinity to water
c) strong hatred to water d) inertness to water
6. The endarch condition is the characteristic feature of:
a) root b) stem c) leaves d) flower
Explanation: In stems, protoxylem lies towards the centre (pith) and metaxylem lies towards the periphery (endarch).
7. Pharyngeal ganglion in leech is a part of:
a) excretory system b) nervous system c) reproductive system d) respiratory system
8. Which of the following process requires energy?
a) active transport b) diffusion c) osmosis d) all of them
Explanation: Active transport moves molecules against a concentration gradient using ATP energy.
9. Which nervous band connects the two cerebral hemispheres of brain?
a) thalamus b) hypothalamus c) corpus callosum d) pons
10. Identify the exocrine gland:
a) pituitary gland b) adrenal gland c) salivary gland d) thyroid gland
Explanation: Salivary glands secrete saliva through ducts, whereas pituitary, adrenal, and thyroid are ductless endocrine glands.
11. A single highly coiled tube where sperms are stored, get concentrated and mature is known as:
a) epididymis b) vasa efferentia c) vas deferens d) seminiferous tubules
12. The centromere is found at the centre of the _______ chromosome.
a) telocentric b) metacentric c) sub-metacentric d) acrocentric
13. State Newton's second law.
The force acting on a body is directly proportional to the rate of change of linear momentum of the body and the change in momentum takes place in the direction of the force.
Formula: $F = ma$.
14. Distinguish between ideal gas and real gas.
| Ideal Gas | Real Gas |
|---|---|
| Atoms or molecules do not interact with each other. | Atoms or molecules interact with each other with attractive forces. |
| Obeys Boyle's law, Charles's law, and Avogadro's law under all conditions. | Obeys gas laws only at low pressure and high temperature. |
15. Fill in the blanks: Atoms of different elements having _______ mass number, but _______ atomic numbers are called isobars.
16. What is rust? Give the equation for formation of rust.
When iron is exposed to moist air, it forms a reddish-brown hydrated ferric oxide coating on its surface called rust.
Chemical Equation: $4\text{Fe} + 3\text{O}_2 + x\text{H}_2\text{O} \rightarrow \mathbf{2\text{Fe}_2\text{O}_3 \cdot x\text{H}_2\text{O}}$ (Rust).
17. The aquatic animals live more in cold region. Why?
The solubility of a gas in a liquid increases with a decrease in temperature. Therefore, cold water holds a significantly higher concentration of dissolved oxygen, allowing aquatic animals to respire more efficiently.
18. Why are the rings of cartilages found in trachea of rabbit?
C-shaped cartilaginous rings support the tracheal wall and prevent it from collapsing, ensuring uninterrupted passage of air during respiration.
19. Match the following:
A) Nissl's granules — Forebrain
B) Hypothalamus — Peripheral nervous system
C) Cerebellum — Cyton
D) Schwann cell — Hind brain
A) Nissl's granules — Cyton
B) Hypothalamus — Forebrain
C) Cerebellum — Hind brain
D) Schwann cell — Peripheral nervous system
20. Identify the parts A, B, C, and D in the given diagram of a pollen grain:
[Diagram: Cross-section of an angiospermic pollen grain showing outer wall, inner wall, generative cell, and vegetative nucleus]
A — Exine (outer spiny layer)
B — Intine (inner cellulose/pectin layer)
C — Generative cell
D — Vegetative nucleus
21. Identify whether the statement is True or False. Correct the false statement: "Hybrid is an offspring from a cross between genetically different parent."
22. [Compulsory] For a person with hypermetropia, the near point has moved to 1.5 m. Calculate the focal length of the correction lens in order to make his eyes normal (near point of normal eye $D = 25\text{ cm} = 0.25\text{ m}$).
Given: Defective near point $d = 1.5\text{ m}$, normal near point $D = 0.25\text{ m}$.
Focal length of convex lens formula:
$$f = \frac{d \cdot D}{d - D} = \frac{1.5 \times 0.25}{1.5 - 0.25} = \frac{0.375}{1.25} = \mathbf{0.3\text{ m}}\text{ (or } \mathbf{+30\text{ cm}}\text{)}$$
23. Classify the types of force based on their application.
Based on the direction of application, parallel forces are classified into:
1. Like Parallel Forces: Two or more forces of equal or unequal magnitude acting along the same direction parallel to each other.
2. Unlike Parallel Forces: Two or more forces of equal or unequal magnitude acting along opposite directions parallel to each other.
24. a) Differentiate convex lens and concave lens. b) Define one calorie.
a) Differentiation:
| Convex Lens | Concave Lens |
|---|---|
| Thicker at the centre, thinner at edges. | Thinner at the centre, thicker at edges. |
| Converging lens. | Diverging lens. |
| Produces mostly real and inverted images. | Always produces virtual and erect images. |
| Used to correct hypermetropia. | Used to correct myopia. |
25. a) What is meant by electric current? b) Name and define its unit.
a) Electric current: The rate of flow of electric charges across any cross-section of a conductor ($I = Q / t$).
b) Unit: The SI unit of electric current is ampere (A).
Definition of 1 Ampere: When an electric charge of 1 coulomb flows through any cross-section of a conductor in 1 second, the current flowing through it is said to be 1 ampere ($1\text{ A} = 1\text{ C} / 1\text{ s}$).
26. $\text{N}_2 + 3\text{H}_2 \rightarrow 2\text{NH}_3$ (The atomic mass of nitrogen is 14 and that of hydrogen is 1). Fill in the blanks:
1 Mole of nitrogen (_______ g) + 3 Moles of hydrogen (_______ g) → 2 Moles of ammonia (_______ g)
• 1 mole of $\text{N}_2 = 1 \times (14 \times 2) = \mathbf{28\text{ g}}$
• 3 moles of $\text{H}_2 = 3 \times (1 \times 2) = \mathbf{6\text{ g}}$
• 2 moles of $\text{NH}_3 = 2 \times [14 + (3 \times 1)] = 2 \times 17 = \mathbf{34\text{ g}}$
Verification: Reactants ($28\text{ g} + 6\text{ g} = 34\text{ g}$) = Products ($34\text{ g}$).
27. a) What happens when $\text{MgSO}_4 \cdot 7\text{H}_2\text{O}$ is heated? Write the appropriate equation. b) Define solubility.
a) When magnesium sulphate heptahydrate (Epsom salt) is heated, it loses seven water molecules of crystallization and turns into anhydrous magnesium sulphate:
$$\text{MgSO}_4 \cdot 7\text{H}_2\text{O} \xrightleftharpoons[\text{Cooling}]{\text{Heating}} \text{MgSO}_4 + 7\text{H}_2\text{O}$$ b) Solubility: The number of grams of a solute that can dissolve in 100 g of a solvent to form its saturated solution at a given temperature and pressure.
28. List out the functions of mitochondria.
1. Main site for aerobic respiration, producing ATP molecules (powerhouse of the cell).
2. Helps maintain the normal physiological concentration of calcium ions within the cell.
3. Regulates cellular metabolic activities and plays a role in apoptosis (programmed cell death).
29. a) Write the dental formula of rabbit. b) Who discovered Rh factor? Why was it named so?
a) Dental formula of rabbit: $(\text{I } 2/1, \text{C } 0/0, \text{PM } 3/2, \text{M } 3/3)$ or $\mathbf{2033 / 1023}$.
b) Rh factor: Discovered by Landsteiner and Wiener in 1940. It was named so because it was first discovered on the surface of red blood cells of the Rhesus monkey.
30. a) Name the parts of Hindbrain. b) What is the role of parathormone?
a) Parts of Hindbrain: 1. Cerebellum 2. Pons 3. Medulla oblongata.
b) Role of Parathormone:
• Regulates calcium and phosphate metabolism in the body.
• Acts on bones, kidneys, and intestine to increase blood calcium levels.
31. a) Correct the statement: "Insect pollinated flowers are characterized by dry and smooth pollen." b) What do you understand by the term phenotype and genotype?
a) Correction: Insect-pollinated flowers have large, spiny, and sticky pollen grains so that they can easily adhere to the bodies of visiting insects (wind-pollinated flowers have dry and smooth pollen).
b) Definitions:
• Phenotype: The observable physical or morphological expression of an organism's traits (e.g., Tall or Dwarf).
• Genotype: The genetic constitution of an organism responsible for a trait (e.g., $TT$, $Tt$, or $tt$).
32. [Compulsory] 16 grams of NaOH is dissolved in 100 grams of water at 25°C to form a saturated solution. Find the mass percentage of solute and solvent.
Mass of solute ($\text{NaOH}$) = $16\text{ g}$
Mass of solvent ($\text{H}_2\text{O}$) = $100\text{ g}$
Mass of solution = $16 + 100 = 116\text{ g}$
• Mass % of solute = $(\text{Mass of solute} / \text{Mass of solution}) \times 100 = (16 / 116) \times 100 = \mathbf{13.79\%}$
• Mass % of solvent = $100 - 13.79 = \mathbf{86.21\%}$
i) Properties of light:
1. Light is a form of energy that propagates as electromagnetic waves.
2. Light always travels along a straight line.
3. It does not require any material medium for propagation and can travel through vacuum.
4. Speed of light in vacuum or air is $c = 3 \times 10^8\text{ m s}^{-1}$.
5. Visible light consists of various wavelengths; violet has the shortest wavelength and red has the longest wavelength.
ii) Differentiate mass and weight:
| Mass | Weight |
|---|---|
| Quantity of matter contained in a body. | Gravitational pull exerted on the body ($W = mg$). |
| Fundamental scalar quantity. | Derived vector quantity directed towards the centre of gravity. |
| Measured in Kilograms (kg). | Measured in Newtons (N). |
| Constant everywhere. | Varies according to acceleration due to gravity ($g$). |
i) Joule's law of heating:
The heat ($H$) generated in a resistor is directly proportional to:
1. The square of current passing through it ($I^2$)
2. The resistance of the conductor ($R$)
3. The time duration for which current flows ($t$)
Formula: $H = I^2Rt$.
ii) Ideal gas equation derivation:
According to Boyle's law: $PV = \text{constant}$ (or $V \propto 1/P$)
According to Charles's law: $V / T = \text{constant}$ (or $V \propto T$)
According to Avogadro's law: $V / n = \text{constant}$ (or $V \propto n$)
Combining these three equations:
$$\frac{PV}{nT} = \text{constant}$$ Since $n = \mu N_A$, we can write $\frac{PV}{\mu N_A T} = k_B$ (Boltzmann constant).
$PV = \mu N_A k_B T$.
Substituting Universal Gas Constant $R = N_A k_B$ ($8.31\text{ J mol}^{-1}\text{ K}^{-1}$):
$$\mathbf{PV = RT}\quad \text{(for 1 mole of gas)}$$
i) Smelting of iron:
Roasted iron ore ($\text{Fe}_2\text{O}_3$), coke ($\text{C}$), and limestone ($\text{CaCO}_3$) in an $8:4:1$ ratio are fed into a blast furnace:
• Combustion Zone (1500°C): $\text{C} + \text{O}_2 \rightarrow \text{CO}_2 + \text{Heat}$
• Fusion Zone (1000°C): $\text{CO}_2 + \text{C} \rightarrow 2\text{CO}$; $\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2$; $\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3\text{ (fusible slag)}$
• Reduction Zone (400°C): $\text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2$
Molten pig iron collects at the bottom and slag floats above it.
ii) Passive state of aluminium:
Dilute or concentrated Nitric acid ($\text{HNO}_3$) renders aluminium passive because it forms a protective, non-porous layer of aluminium oxide ($\text{Al}_2\text{O}_3$) on its surface that prevents further chemical attack.
i) Salient features of Modern Atomic Theory:
1. An atom is no longer indivisible; it is composed of subatomic particles (electrons, protons, neutrons).
2. Atoms of the same element may possess different atomic masses (Isotopes: $_{17}\text{Cl}^{35}$, $_{17}\text{Cl}^{37}$).
3. Atoms of different elements may have the same atomic mass (Isobars: $_{18}\text{Ar}^{40}$, $_{20}\text{Ca}^{40}$).
4. Atoms of one element can be transmuted into atoms of another element (Artificial transmutation).
5. Atom is the smallest particle that participates in a chemical reaction, and mass can be transformed into energy ($E = mc^2$).
ii) Difference between Hygroscopic and Deliquescent substances:
| Hygroscopic Substances | Deliquescent Substances |
|---|---|
| Absorb moisture from air without dissolving. | Absorb sufficient moisture from air and dissolve in it. |
| Do not change their physical state (remain solid/liquid). | Change their physical state from crystalline solid to liquid solution. |
| E.g., Conc. $\text{H}_2\text{SO}_4$, Silica gel, Quicklime ($\text{CaO}$). | E.g., Solid $\text{NaOH}$, $\text{KOH}$, $\text{FeCl}_3$. |
i) Physiological effects of gibberellins:
1. Induces remarkable elongation of internodes in dwarf varieties (e.g., genetically dwarf corn and pea plants).
2. Induces sudden stem elongation followed by flowering in rosette plants, known as "bolting".
3. Promotes the development of male flowers in monoecious plants (e.g., Cucurbits).
4. Overcomes natural seed dormancy and breaks the dormancy of potato tubers.
5. Induces parthenocarpy to produce seedless fruits (e.g., seedless grapes and tomatoes).
ii) Biological significance of DNA:
• Acts as the hereditary blueprint, carrying genetic instructions from one generation to the next.
• Contains instructions for protein synthesis essential for cell structure and metabolism.
• Controls growth, differentiation, and development of all living organisms.
i) Anatomical differences between Monocot root and Dicot root:
| Tissues | Dicot Root (e.g., Bean) | Monocot Root (e.g., Maize) |
|---|---|---|
| Xylem bundles | Tetrarch (usually four bundles) | Polyarch (many bundles) |
| Cambium | Present (formed during secondary growth) | Absent |
| Secondary growth | Present | Absent |
| Pith | Absent or inconspicuous | Present and well-developed |
| Conjunctive tissue | Parenchymatous | Sclerenchymatous |
ii) Types of neurons based on structure:
1. Unipolar neurons: Only one process arises from the cyton, serving as both axon and dendron (found in early embryonic stages).
2. Bipolar neurons: Two processes emerge from opposite poles of the cyton — one axon and one dendron (found in retina of the eye and olfactory epithelium).
3. Multipolar neurons: Many dendrons and a single long axon emerge from the cell body (found in cerebral cortex).
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