10th Science Quarterly Exam Question Paper & Answer Key 2026 | Thoothukudi District (EM)
Gear up for your upcoming board exams with the official 10th Standard Science Quarterly Exam 2026 Question Paper and Answer Key released for Thoothukudi District (English Medium). This comprehensive study resource provides the complete regional examination paper alongside verified, step-by-step solutions for the Physics, Chemistry, and Biology sections. Self-evaluating with this authentic district paper will help English medium students grasp core scientific concepts, master the marking scheme, and build the speed and confidence necessary for the final board exams.
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COMMON QUARTERLY EXAMINATION - 2026
1. Plotting a graph for momentum on the x-axis and time on the y-axis, the slope of the momentum-time graph gives:
a) Impulsive force b) Acceleration c) Force d) Rate of force
Explanation: By Newton's second law, rate of change of momentum with respect to time represents force.
2. The eye defect "Presbyopia" can be corrected by:
a) convex lens b) concave lens c) convex mirror d) Bi-focal lenses
3. If a substance is heated or cooled, the change in mass of that substance is:
a) positive b) negative c) zero d) none of the above
Explanation: Heat transfer alters temperature and volume, but the mass of the substance remains strictly conserved.
4. 1 Horse power is equal to:
a) 746 watts b) 764 watts c) 467 watts d) 647 watts
5. One mole of any substance contains _______ molecules.
a) 6.023 × 1023 b) 6.023 × 10−23 c) 3.0115 × 1023 d) 12.046 × 1023
Explanation: This value is known as Avogadro's number.
6. The number of periods and groups in the modern periodic table are:
a) 6, 16 b) 7, 17 c) 8, 18 d) 7, 18
7. A 25% alcohol solution means:
a) 25 ml alcohol in 100 ml of water b) 25 ml alcohol in 25 ml water
c) 25 ml alcohol in 75 ml of water d) 75 ml alcohol in 25 ml of water
Explanation: 25 ml of solute dissolved in 75 ml of solvent forms 100 ml of total solution (25% v/v).
8. Mammals are _______ animals.
a) cold blooded b) warm blooded c) poikilothermic d) all the above
9. Match the following:
1. Nissl's granules — i) Forebrain
2. Hypothalamus — ii) Peripheral nervous system
3. Cerebellum — iii) Cyton
4. Schwann cell — iv) Hindbrain
a) 1-iii, 2-i, 3-iv, 4-ii b) 1-iv, 2-iii, 3-i, 4-ii
c) 1-i, 2-ii, 3-iii, 4-iv d) 1-iv, 2-iii, 3-ii, 4-i
10. The life-saving hormone is:
a) Melatonin b) Cortisol c) Thyroxine d) Estrogen
11. The plant which propagates with the help of its leaves is:
a) onion b) neem c) ginger d) Bryophyllum
12. 9:3:3:1 ratio is due to:
a) segregation b) crossing over c) independent assortment d) recessiveness
13. Define Inertia. Give its classification.
Inertia: The inherent property of a body to resist any change in its state of rest or the state of uniform motion unless acted upon by an external unbalanced force.
Classification:
1. Inertia of rest
2. Inertia of motion
3. Inertia of direction
14. Differentiate between a convex lens and a concave lens.
| Convex Lens | Concave Lens |
|---|---|
| Thicker in the middle and thinner at edges. | Thinner in the middle and thicker at edges. |
| Converging lens. | Diverging lens. |
| Produces mostly real and inverted images. | Always produces virtual and erect images. |
15. State the law of volume (Charles's Law).
According to Charles's law, at constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute temperature.
Formula: V ∝ T or V / T = Constant.
16. What is the role of the earth wire in domestic circuits?
The earth wire provides a low resistance path to the electric current. In case of any leakage of current to the metallic body of an appliance, the current safely flows to the earth, preventing severe electric shocks to the user.
17. What is Amalgam? Give an example.
An amalgam is an alloy of mercury with another metal.
Example: Silver-tin amalgam (used for dental filling).
18. What is respiratory quotient (RQ)?
Respiratory quotient is the ratio of the volume of carbon dioxide released to the volume of oxygen consumed during respiration.
Formula: RQ = Volume of CO2 liberated / Volume of O2 consumed.
19. Who discovered Rh factor? Why was it called so?
Rh factor was discovered by Landsteiner and Wiener in 1940. It was called so because it was first detected in the blood of Rhesus monkey.
20. Draw the diagram of thyroid gland and label the parts:
[Diagram: Human Thyroid gland positioned in the neck region attached to the trachea]
A — Thyroid cartilage / Larynx
B — Lateral lobe of Thyroid gland
C — Trachea
D — Cartilage rings of Trachea
21. Write the characteristics of insect-pollinated flowers.
1. Flowers are brightly colored, showy, and large in size.
2. They produce sweet scent and nectar to attract insects.
3. Pollen grains are larger and have a spiny, sticky exine to stick to the insect's body.
22. [Compulsory] Calculate the volume of ethanol in 200 ml solution of 20% v/v aqueous solution of ethanol.
Volume percentage (v/v) = (Volume of solute / Volume of solution) × 100
20 = (Volume of ethanol / 200) × 100
20 = (Volume of ethanol / 2)
Volume of ethanol = 20 × 2 = 40 ml.
23. State Newton's laws of motion.
• Newton's First Law: Every object continues to remain in its state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.
• Newton's Second Law: The rate of change of linear momentum of a body is directly proportional to the applied external force and acts in the direction of the force (F = ma).
• Newton's Third Law: For every action, there is an equal and opposite reaction (FA = −FB).
24. List any five properties of light.
1. Light is a form of energy that propagates as electromagnetic waves.
2. Light always travels along a straight line path.
3. Light does not require any material medium for its propagation.
4. The speed of light in vacuum or air is c = 3 × 108 m s−1.
5. Different colors of visible light have different wavelengths and frequencies; violet has the shortest wavelength and red has the longest wavelength.
25. Differentiate between atoms and molecules.
| Atom | Molecule |
|---|---|
| Smallest particle of an element. | Smallest particle of an element or compound. |
| Usually does not exist in free state (except noble gases). | Can exist independently in free state. |
| Highly reactive (except noble gases). | Less reactive compared to atoms. |
| Does not have chemical bonds. | Atoms in a molecule are held by chemical bonds. |
26. Write short notes on: a) Saturated solution b) Unsaturated solution.
a) Saturated Solution: A solution in which no more solute can be dissolved in a given amount of solvent at a specified temperature (e.g., 36 g of NaCl in 100 g of water at 25°C).
b) Unsaturated Solution: A solution that contains less amount of solute than that required for saturation at a given temperature; more solute can be dissolved in it (e.g., 10 g or 20 g of NaCl in 100 g of water at 25°C).
27. a) How is diastema formed in rabbit? b) Why is the dentition of rabbit called heterodont?
a) Diastema: In rabbits, canine teeth are completely absent. The toothless gap between the incisors and the premolars is called diastema. It helps in mastication and chewing of herbivorous food.
b) Heterodont: The teeth of rabbits are of different types with distinct structures and functions (incisors, premolars, and molars). Therefore, the dentition is described as heterodont.
28. Enumerate the functions of blood.
1. Transports respiratory gases (oxygen and carbon dioxide).
2. Transports digested food nutrients to all cells.
3. Transports hormones and nitrogenous waste products (urea, uric acid).
4. Regulates body temperature, water balance, and maintains acid-base balance (pH).
5. Provides defense against bacterial infections through white blood cells (WBCs) and antibodies.
29. a) Differentiate between medullated and non-medullated nerve fibre. b) Identify L, M, N, O, and P:
Our body contains a large number of cells 'L' which are the longest cells. 'L' has long and short branches called 'M' and 'N' respectively. There is a gap 'O' between two 'L' cells, through which nerve impulse transfers by release of chemical substance 'P'.
a) Differentiation:
• Medullated nerve fibre: Axon is covered with a protective myelin sheath. Conduction of impulses is faster.
• Non-medullated nerve fibre: Axon is not covered by a myelin sheath. Conduction of impulses is comparatively slower.
b) Identification:
i) Cell 'L' — Neuron (Nerve cell)
ii) 'M' — Axon; 'N' — Dendron (Dendrites)
iii) Gap 'O' — Synapse
iv) Chemical substance 'P' — Neurotransmitter (e.g., Acetylcholine)
30. a) Name the gaseous plant hormone. b) Describe its three different actions in plants.
a) Gaseous hormone: Ethylene.
b) Actions in plants:
1. Promotes ripening of fleshy fruits (like banana, apple, tomato).
2. Promotes abscission of leaves, flowers, and fruits.
3. Breaks the dormancy of buds, seeds, and storage organs.
31. a) What do you understand by the terms phenotype and genotype? b) What are allosomes?
a) Definitions:
• Phenotype: The observable physical or morphological appearance of an individual for a particular trait (e.g., Tall or Dwarf).
• Genotype: The genetic makeup or gene constitution responsible for the expression of a trait (e.g., TT, Tt, or tt).
b) Allosomes: Chromosomes that determine the sex of an individual are called allosomes or sex chromosomes (X and Y chromosomes).
32. [Compulsory] Three resistors R1 = 5 Ω, R2 = 10 Ω, and R3 = 20 Ω are connected in parallel across a 10 V battery. Calculate: a) Current through each resistor b) Total current in the circuit.
Given: V = 10 V, R1 = 5 Ω, R2 = 10 Ω, R3 = 20 Ω.
a) Current through each resistor:
I1 = V / R1 = 10 / 5 = 2 A
I2 = V / R2 = 10 / 10 = 1 A
I3 = V / R3 = 10 / 20 = 0.5 A
b) Total current in the circuit (I):
I = I1 + I2 + I3 = 2 + 1 + 0.5 = 3.5 A.
i) Rules for image formation by a convex lens:
• Rule 1: A ray of light incident parallel to the principal axis passes through the principal focus on the other side after refraction.
• Rule 2: A ray of light passing through the optical centre passes straight through the lens without any deviation.
• Rule 3: A ray of light directed towards the principal focus emerges parallel to the principal axis after refraction.
ii) Linear expansion vs Superficial expansion:
• Linear expansion: Expansion in length of a solid body when heated (ΔL / L0 = αL ΔT).
• Superficial expansion: Expansion in surface area of a solid body when heated (ΔA / A0 = αA ΔT).
i) Electric current: The rate of flow of electric charges in a conductor (I = Q / t).
ii) Unit: The SI unit of electric current is ampere (A).
iii) Measurement: Electric current is measured using an Ammeter. It must always be connected in series with the electrical circuit.
iv) Merits of LED bulbs:
1. Consumes very low power and is energy efficient.
2. Has a very long lifespan compared to incandescent bulbs.
3. Does not contain harmful mercury and produces minimal heat dissipation.
i) Corrosion: The slow and gradual destruction or chemical deterioration of metals by the action of air, moisture, or chemical substances present in the environment.
ii) Types of corrosion: Dry corrosion (chemical corrosion) and Wet corrosion (electrochemical corrosion).
iii) Methods of prevention:
1. Galvanization: Coating zinc on iron surfaces.
2. Electroplating: Coating a superior metal over a base metal using electric current.
3. Alloying: Modifying properties by making alloys (e.g., stainless steel).
4. Applying barriers: Coating with paint, grease, or oil.
i) Factors affecting solubility:
1. Nature of solute and solvent: Polar solutes dissolve in polar solvents; non-polar solutes dissolve in non-polar solvents ("Like dissolves like").
2. Temperature: For endothermic processes, solubility increases with temperature; for exothermic processes, solubility decreases with temperature. Solubility of gases in liquids decreases with increasing temperature.
3. Pressure: Increasing pressure increases the solubility of gases in liquids (Henry's Law). Pressure has no significant effect on solids in liquids.
ii) Heating of Epsom salt: When magnesium sulphate heptahydrate (MgSO4·7H2O) is heated, it loses all seven water molecules of crystallization and turns into anhydrous magnesium sulphate:
MgSO4·7H2O ↔ MgSO4 + 7H2O (Heating / Cooling).
i) Classification of neurons based on structure:
1. Unipolar neurons: Only one nerve process arises from the cyton, which acts both as axon and dendron (found in early embryonic stages).
2. Bipolar neurons: Two processes arise from the cyton, one as an axon and the other as a dendron (found in the retina of the eye).
3. Multipolar neurons: Many dendrons and a single long axon arise from the cyton (found in the cerebral cortex).
ii) Reflex arc: The structural and functional neural pathway traversed by an electrical nerve impulse during a reflex action (comprising receptor, sensory neuron, interneuron, motor neuron, and effector organ).
1. Funicle (Funiculus): The stalk by which the ovule is attached to the placenta of the ovary.
2. Hilum: The point of attachment of the body of the ovule with the funicle.
3. Nucellus: The central mass of parenchymatous nutritive tissue enveloped by protective integuments.
4. Integuments: Outer and inner protective coverings surrounding the nucellus.
5. Micropyle: A narrow pore left uncovered by the integuments at the apex for pollen tube entry.
6. Chalaza: The basal swollen region where the nucellus, integuments, and funicle merge.
7. Embryo Sac (Female gametophyte): A 7-celled, 8-nucleate structure containing:
• Egg apparatus at the micropylar end (1 egg cell and 2 synergids).
• Antipodal cells (3 cells) at the chalazal end.
• Central cell containing 2 polar nuclei that fuse to form the secondary nucleus.
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