ADEPT YOURSELF
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CBSE Class X — Science Sample Question Paper 1
Academic Session: 2026–2027
General Instructions:
- This question paper consists of 39 questions.
- All questions are compulsory. Internal choices are provided in some questions.
- The question paper contains questions of 1, 2, 3, 4 and 5 marks.
- Draw neat and properly labelled diagrams wherever required.
- Show all necessary steps in numerical problems.
- Use of calculators is not permitted.
SECTION A — BIOLOGY
Q1.
Select the correct statement regarding bile juice secreted by the human liver:
[1]
Q2.
The opening and closing of stomata is mainly controlled by changes in:
[1]
Q3.
Which sequence correctly represents a reflex arc?
[1]
Q4.
A pure tall pea plant (TT) is crossed with a pure dwarf pea plant (tt). All F₁ plants are tall because:
[1]
Q5.
If fertilisation does not occur, the thickened lining of the uterus is shed approximately every:
[1]
Q6.
If producers capture 20,000 J of energy, how much energy will approximately reach the tertiary consumer according to the 10% law?
[1]
Q7.
Assertion (A): In human beings, the sex of the child is determined genetically by the father.
Reason (R): An ovum carries an X chromosome, whereas sperm may carry either X or Y chromosome.
[1]Reason (R): An ovum carries an X chromosome, whereas sperm may carry either X or Y chromosome.
Q8.Assertion (A):
Non-biodegradable pesticides may show biomagnification in a food chain.
Reason (R): Such substances are not readily broken down and may accumulate in organisms.[1]
Reason (R): Such substances are not readily broken down and may accumulate in organisms.[1]
Q9.
State the site of complete digestion of carbohydrates, proteins and fats in the human alimentary canal. Name the end products of fat digestion.
[2]
Q10.
State two differences between transport through xylem and translocation through phloem.
[2]
Q11.
(a) What is phototropism? Name the plant hormone responsible for this directional growth.
(b) Explain how this hormone causes a shoot to bend towards light.[3]
(b) Explain how this hormone causes a shoot to bend towards light.[3]
Q12.
In a monohybrid cross between RR and rr:
(a) Give the genotype and phenotype of F₁ generation.
(b) Show the self-cross of F₁ plants.
(c) State the phenotypic and genotypic ratios in F₂ generation.[3]
(a) Give the genotype and phenotype of F₁ generation.
(b) Show the self-cross of F₁ plants.
(c) State the phenotypic and genotypic ratios in F₂ generation.[3]
Q13.
Why is depletion of the ozone layer harmful? Name the chemicals mainly responsible for ozone depletion and the international protocol signed in 1987 to control them.
[3]
Q14.Read the following passage and answer the questions:
The endocrine system coordinates several body functions through hormones.
The pancreas secretes insulin, which helps regulate blood glucose.
The thyroid gland requires iodine to synthesise thyroxine.
The pituitary gland secretes growth hormone.
(a) Why is iodised salt recommended? [1]
(b) Name the gland which has both endocrine and exocrine functions. Name one digestive enzyme and one hormone secreted by it. [1]
(c) Explain how insulin helps maintain normal blood glucose levels. [2]
(b) Name the gland which has both endocrine and exocrine functions. Name one digestive enzyme and one hormone secreted by it. [1]
(c) Explain how insulin helps maintain normal blood glucose levels. [2]
OR
(c) Differentiate between nervous control and hormonal control on the basis of speed and duration of effect. [2]Q15.(a) Draw a neat labelled diagram of the human female reproductive system.
(b) State one function each of the placenta and scrotum.
(c) Describe any two methods of contraception and explain their mechanisms.[5]
(b) Describe ultrafiltration, selective reabsorption and tubular secretion.
(c) Why is final urine different from the initial filtrate?
(b) State one function each of the placenta and scrotum.
(c) Describe any two methods of contraception and explain their mechanisms.[5]
OR
(a) Name the structural and functional unit of the kidney.(b) Describe ultrafiltration, selective reabsorption and tubular secretion.
(c) Why is final urine different from the initial filtrate?
SECTION B — CHEMISTRY
Q16.
Zinc reacts with dilute hydrochloric acid. The gas evolved:
[1]
Q17.
A solution gives a white precipitate with barium chloride which does not dissolve in dilute hydrochloric acid. The ion present is most likely:
[1]
Q18.
Which pair consists of amphoteric oxides?
[1]
Q19.
The functional group present in ethanoic acid is:
[1]
Q20.
Copper is heated in air and forms a black coating. Hydrogen passed over the black coating restores copper. This represents:
[1]
Q21.Assertion (A):
Copper develops a green coating when exposed to moist air for a long time.
Reason (R): Copper reacts slowly with oxygen, carbon dioxide and moisture.[1]
Reason (R): Copper reacts slowly with oxygen, carbon dioxide and moisture.[1]
Q22.
Name the salt produced when baking soda is heated. Write the balanced chemical equation and state one use of baking soda.
[2]
Q23.
A metal M reacts vigorously with cold water to form an alkaline solution and hydrogen gas.
(a) Identify M.
(b) Write the balanced chemical equation.
(c) State its group in the modern periodic table.[3]
(a) Identify M.
(b) Write the balanced chemical equation.
(c) State its group in the modern periodic table.[3]
OR
Differentiate between calcination and roasting. Give one balanced equation for each.Q24.
Explain the properties of catenation and tetravalency of carbon. How do these properties contribute to the formation of a large number of carbon compounds?
[3]
Q25.Read the following passage:
Highly reactive metals cannot generally be extracted by reduction with carbon.
Aluminium is obtained by electrolytic reduction. In the Thermite reaction,
aluminium reduces iron(III) oxide to iron.
(a) Why cannot carbon reduce aluminium oxide? [1]
(b) Write the balanced Thermite reaction. [1]
(c) State the electrode reactions and electrolyte used in electrolytic refining of copper. [2]
(b) Write the balanced Thermite reaction. [1]
(c) State the electrode reactions and electrolyte used in electrolytic refining of copper. [2]
OR
(c) Iron and zinc are separately placed in copper sulphate solution. State which reactions occur and write the equations. [2]Q26.(a) Define esterification. Write the reaction between ethanol and ethanoic acid in the presence of concentrated sulphuric acid.
(b) What happens when an ester is treated with aqueous NaOH? Name the reaction.
(c) Draw electron-dot structures of ethene and ethyne.[5]
(b) Why does soap form scum in hard water?
(c) Give chemical tests to distinguish ethene from ethane and ethanol from ethanoic acid.
(b) What happens when an ester is treated with aqueous NaOH? Name the reaction.
(c) Draw electron-dot structures of ethene and ethyne.[5]
OR
(a) Explain the cleansing action of soap.(b) Why does soap form scum in hard water?
(c) Give chemical tests to distinguish ethene from ethane and ethanol from ethanoic acid.
Q27.
Write balanced chemical equations for:
(a) Calcium carbonate reacting with dilute hydrochloric acid.
(b) Bleaching powder reacting with atmospheric carbon dioxide.[2]
(a) Calcium carbonate reacting with dilute hydrochloric acid.
(b) Bleaching powder reacting with atmospheric carbon dioxide.[2]
SECTION C — PHYSICS
Q28.
An optical device produces a virtual, erect and magnified image when an object is placed between its pole and focus. The device is:
[1]
Q29.
Which colour suffers maximum deviation through a glass prism?
[1]
Q30.
A wire of length L and area A has resistance R. Another wire of the same material has length 2L and the same resistance R. Its cross-sectional area is:
[1]
Q31.
The magnetic field inside a long current-carrying solenoid is represented by:
[1]
Q32.Assertion (A):
A compass needle placed near a current-carrying conductor gets deflected.
Reason (R): Electric current produces a magnetic field around a conductor.[1]
Reason (R): Electric current produces a magnetic field around a conductor.[1]
Q33.Assertion (A):
The sky appears dark to an astronaut in outer space.
Reason (R): There is essentially no atmosphere in outer space to scatter sunlight.[1]
Reason (R): There is essentially no atmosphere in outer space to scatter sunlight.[1]
Q34.
An object is placed 15 cm in front of a concave mirror of focal length 10 cm. Calculate the position, magnification and nature of the image formed.
[2]
Q35.
State Snell’s law of refraction. Write the relation between refractive index and the speeds of light in two media.
[2]
OR
A ray of light travels from water into glass obliquely. Does it bend towards or away from the normal? Give a reason.Q36.(a) Why do stars appear to twinkle while planets generally do not?
(b) Why does the Sun appear reddish at sunrise?[3]
(b) Why does the Sun appear reddish at sunrise?[3]
Q37.Three resistors of 4 Ω, 6 Ω and 12 Ω are connected in parallel across a 6 V battery.
(a) Calculate the equivalent resistance.
(b) Calculate the total current.
(c) Calculate the current through the 6 Ω resistor.[3]
(a) Calculate the equivalent resistance.
(b) Calculate the total current.
(c) Calculate the current through the 6 Ω resistor.[3]
Q38.Read the following passage:
Electric power is given by P = VI = I²R = V²/R.
Household appliances are connected in parallel.
Nichrome is commonly used in heating elements because of its suitable resistance
and ability to withstand high temperatures.
(a) Why is nichrome preferred for heating elements? [1]
(b) A 220 V, 1100 W electric kettle is used. Calculate the current drawn. [1]
(c) A 2000 W geyser operates for 2 hours daily and four 100 W lamps operate for 5 hours daily. Calculate the electrical energy consumed in 30 days. [2]
(b) A 220 V, 1100 W electric kettle is used. Calculate the current drawn. [1]
(c) A 2000 W geyser operates for 2 hours daily and four 100 W lamps operate for 5 hours daily. Calculate the electrical energy consumed in 30 days. [2]
OR
(c) Two bulbs rated 220 V, 60 W and 220 V, 100 W are connected in parallel. Which has greater resistance and which glows brighter? Give reasons. [2]Q39.(a) A convex lens of focal length 20 cm forms a real, inverted image three times the size of the object. Calculate the object distance and image distance. Draw a ray diagram.
(b) Define the power of a lens. A person wears spectacles of power –2.5 D. Identify the type of lens and calculate its focal length.[5]
(b) Describe an experiment demonstrating the force experienced by a current-carrying conductor in a magnetic field.
(c) State three factors affecting the magnitude of the force.
(b) Define the power of a lens. A person wears spectacles of power –2.5 D. Identify the type of lens and calculate its focal length.[5]
OR
(a) State Fleming’s Left-Hand Rule.(b) Describe an experiment demonstrating the force experienced by a current-carrying conductor in a magnetic field.
(c) State three factors affecting the magnitude of the force.
ADEPT YOURSELF
ANSWER KEY & MARKING POINTS
| Q.No. | Answer / Value Points |
|---|---|
| 1 | (c) Emulsifies fats into smaller droplets. |
| 2 | (c) Changes in water content of guard cells. |
| 3 | (b) Receptor → Sensory neuron → Spinal cord → Motor neuron → Effector. |
| 4 | (a) Tallness is dominant. |
| 5 | (b) 28 days. |
| 6 | (c) 20 J. |
| 7 | Both A and R are true and R correctly explains A. |
| 8 | Both A and R are true and R correctly explains A. |
| 9 | Small intestine; fatty acids and glycerol. |
| 10 | Xylem mainly transports water and minerals; phloem transports food. Xylem transport is mainly upward, whereas phloem translocation can occur in different directions according to source and sink. |
| 11 | Phototropism is growth in response to light. Auxin accumulates more on the shaded side, causing greater elongation there and bending towards light. |
| 12 | F₁: Rr, all round. F₂: RR, Rr, Rr, rr. Phenotypic ratio = 3:1; genotypic ratio = 1:2:1. |
| 13 | Ozone absorbs harmful UV radiation. CFCs are major ozone-depleting substances. Montreal Protocol, 1987. |
| 14 | (a) Iodine is required for thyroxine synthesis. (b) Pancreas; e.g. trypsin/lipase and insulin. (c) Insulin promotes uptake/storage of glucose and lowers blood glucose. |
| 16 | (b) Hydrogen burns with a pop sound. |
| 17 | (b) Sulphate ion. |
| 18 | (b) Al₂O₃ and ZnO. |
| 19 | (c) –COOH. |
| 20 | (b) Oxidation followed by reduction. |
| 21 | Both A and R are true and R correctly explains A. |
| 22 | Na₂CO₃. 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂. Use: antacid/baking agent. |
| 23 | M = sodium. 2Na + 2H₂O → 2NaOH + H₂. Group 1. |
| 24 | Catenation: self-linking of carbon atoms. Tetravalency: carbon forms four covalent bonds. |
| 25 | Al has greater affinity for oxygen than carbon. Thermite: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + heat. |
| 26 | CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O. With NaOH, saponification occurs. |
| 27 | CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂. |
| 28 | (b) Concave mirror. |
| 29 | (d) Violet. |
| 30 | (c) 2A. |
| 31 | (b) Parallel straight lines. |
| 32 | Both A and R are true and R correctly explains A. |
| 33 | Both A and R are true and R correctly explains A. |
| 34 | Using mirror formula: v = –30 cm; magnification = –2. Image is real, inverted and magnified. |
| 35 | Snell’s law: sin i/sin r = constant. Relative refractive index = speed in first medium / speed in second medium. |
| 36 | Stars twinkle due to atmospheric refraction. Planets are extended sources. The Sun appears reddish at sunrise because shorter wavelengths are scattered more during the longer atmospheric path. |
| 37 | Equivalent resistance = 2 Ω; total current = 3 A; current through 6 Ω resistor = 1 A. |
| 38 | Kettle current = P/V = 1100/220 = 5 A. Daily energy = 6 kWh; 30-day energy = 180 kWh. |
| 39 | For the lens: m = –3, u ≈ –26.67 cm and v = 80 cm. For –2.5 D, lens is concave and f = –0.4 m = –40 cm. |