CBSE Class 10th Science Sample Paper (2024-25)

General Instructions:

1. The question paper comprises five sections – A, B, C, D, and E. All questions are compulsory.
2. Internal choice is provided in some questions. You have to attempt only one of the choices in such questions.
3. All questions in Section A are one-mark questions comprising MCQs, very short answer, and assertion-reason type questions. They are to be answered in one word or one sentence.
4. All questions in Section B are three-mark, short answer type questions. These are to be answered in about 50-60 words each.
5. All questions in Section C are five-mark, long answer type questions. These are to be answered in about 80-90 words each.
6. All questions in Section D are two-mark, case-based questions. These are to be answered in about 30-40 words each.
7. All questions in Section E are four-mark, case study-based questions. These are to be answered in about 100-120 words each.
8. Use of calculators is not permitted.

Section A: Objective Type Questions (1 mark each)

1. Which of the following is a non-renewable source of energy?
   • a) Solar energy
   • b) Wind energy
   • c) Coal
   • d) Hydropower
2. The chemical formula of baking soda is:
   • a) NaCl
   • b) NaHCO₃
   • c) Na₂CO₃
   • d) NaOH
3. Which gas is evolved when zinc reacts with hydrochloric acid?
   • a) Oxygen
   • b) Hydrogen
   • c) Nitrogen
   • d) Carbon dioxide
4. The SI unit of electric current is:
   • a) Volt
   • b) Ampere
   • c) Ohm
   • d) Watt
5. Which of the following is a plant hormone?
   • a) Insulin
   • b) Thyroxine
   • c) Auxin
   • d) Adrenaline
6. Assertion (A): Metals are good conductors of electricity. Reason (R): Metals have free electrons.
   • a) Both A and R are true, and R is the correct explanation of A.
   • b) Both A and R are true, but R is not the correct explanation of A.
   • c) A is true, but R is false.
   • d) A is false, but R is true.

Section B: Short Answer Questions (3 marks each)

7. Explain the process of photosynthesis with a balanced chemical equation.
8. Describe the structure of a neuron and its functions.
9. What are the differences between acids and bases? Provide examples.
10. Explain the working principle of an electric motor.
11. Describe the process of digestion in the human body.

Section C: Long Answer Questions (5 marks each)

12. Explain the carbon cycle with the help of a diagram.
13. Discuss the various methods of contraception and their importance.
14. Describe the process of extraction of metals from their ores.
15. Explain the structure and functioning of the human heart.
16. Discuss the impact of human activities on the environment and suggest measures to reduce pollution.

Section D: Case-Based Questions (2 marks each)

17. Describe the steps to test the presence of starch in a leaf.
18. How would you prepare a temporary mount of a leaf peel to observe stomata?
19. Explain the procedure to determine the pH of a given solution using pH paper.
20. Describe the method to separate the components of a mixture using chromatography.

Section E: Case Study-Based Questions (4 marks each)

21. Read the following passage and answer the questions that follow: "A farmer noticed that his crops were not growing well. He tested the soil and found that it was deficient in nitrogen. He decided to use a nitrogen-based fertilizer to improve the soil quality."

• a) Why is nitrogen important for plant growth?
• b) What are the effects of nitrogen deficiency on plants?
• c) Suggest two natural ways to increase nitrogen content in the soil.
• d) What precautions should the farmer take while using chemical fertilizers?

22. Read the following passage and answer the questions that follow: "A student conducted an experiment to study the effect of different temperatures on the rate of fermentation. She used yeast and sugar solutions and measured the amount of carbon dioxide produced at different temperatures."

• a) What is fermentation?
• b) How does temperature affect the rate of fermentation?
• c) Why is yeast used in fermentation experiments?
• d) What are the by-products of fermentation?

Answer Key

Solution Key for CBSE Class 10th Science Sample Paper (2024-25)

Section A: Objective Type Questions (1 mark each)

1. c) Coal
2. b) NaHCO₃
3. b) Hydrogen
4. b) Ampere
5. c) Auxin
6. a) Both A and R are true, and R is the correct explanation of A.

Section B: Short Answer Questions (3 marks each)

7. Photosynthesis:
   • Photosynthesis is the process by which green plants use sunlight to synthesize foods with the help of chlorophyll.
   • Balanced chemical equation:6CO2

8. Structure of a Neuron:
   • A neuron consists of three main parts: the cell body (soma), dendrites, and axon.
   • Functions:
     • Cell body: Contains the nucleus and cytoplasm.
     • Dendrites: Receive signals from other neurons.
     • Axon: Transmits signals away from the cell body to other neurons or muscles.
9. Differences between Acids and Bases:
   • Acids:
     • Taste sour.
     • Turn blue litmus paper red.
     • Example: Hydrochloric acid (HCl).
   • Bases:
     • Taste bitter.
     • Turn red litmus paper blue.
     • Example: Sodium hydroxide (NaOH).
10. Working Principle of an Electric Motor:
    • An electric motor converts electrical energy into mechanical energy.
    • It works on the principle of the magnetic effect of current.
    • When a current-carrying conductor is placed in a magnetic field, it experiences a force that causes it to move.
11. Process of Digestion in the Human Body:
    • Digestion begins in the mouth where food is chewed and mixed with saliva.
    • The food then moves to the stomach where it is mixed with gastric juices.
    • In the small intestine, digestive enzymes break down the food into nutrients which are absorbed into the bloodstream.
    • The remaining waste is passed to the large intestine and eventually excreted.

Section C: Long Answer Questions (5 marks each)

12. Carbon Cycle:
    • The carbon cycle is the process by which carbon is exchanged between the atmosphere, land, water, and organisms.
    • Diagram: (Include a diagram showing the carbon cycle)
    • Key processes: Photosynthesis, respiration, decomposition, and combustion.
13. Methods of Contraception:
    • Barrier methods: Condoms, diaphragms.
    • Hormonal methods: Birth control pills, patches.
    • Intrauterine devices (IUDs): Copper IUD, hormonal IUD.
    • Importance: Prevents unwanted pregnancies, reduces the risk of sexually transmitted infections (STIs).
14. Extraction of Metals from Ores:
    • Steps involved:
      • Concentration of ore: Removing impurities.
      • Reduction: Converting the concentrated ore into metal.
      • Refining: Purifying the metal.
    • Example: Extraction of iron from hematite.
15. Structure and Functioning of the Human Heart:
    • The heart has four chambers: two atria and two ventricles.
    • Blood flow: Deoxygenated blood enters the right atrium, moves to the right ventricle, and is pumped to the lungs. Oxygenated blood returns to the left atrium, moves to the left ventricle, and is pumped to the body.
    • The heart functions as a pump to circulate blood throughout the body.
16. Impact of Human Activities on the Environment:
    • Deforestation: Leads to loss of biodiversity and increased carbon dioxide levels.
    • Pollution: Air, water, and soil pollution harm ecosystems and human health.
    • Measures to reduce pollution: Use of renewable energy, recycling, afforestation.

Section D: Case-Based Questions (2 marks each)

17. Test for Starch in a Leaf:
    • Boil the leaf in water to kill it.
    • Immerse the leaf in alcohol to remove chlorophyll.
    • Rinse the leaf in warm water and add iodine solution. A blue-black color indicates the presence of starch.
18. Temporary Mount of a Leaf Peel:
    • Take a small piece of leaf peel.
    • Place it on a slide and add a drop of water.
    • Cover with a cover slip and observe under a microscope.
19. Determine pH Using pH Paper:
    • Dip the pH paper into the solution.
    • Compare the color change with the pH scale to determine the pH.
20. Chromatography Method:
    • Place a drop of the mixture on a chromatography paper.
    • Dip the paper in a solvent.
    • The components of the mixture will separate based on their solubility.

Section E: Case Study-Based Questions (4 marks each)

21. Nitrogen-Based Fertilizer Case Study:
    • a) Nitrogen is important for plant growth as it is a key component of chlorophyll and amino acids.
    • b) Nitrogen deficiency leads to stunted growth, yellowing of leaves, and poor yield.
    • c) Natural ways to increase nitrogen: Crop rotation with legumes, adding compost or manure.
    • d) Precautions: Avoid overuse, follow recommended dosages, and ensure proper mixing with soil.
22. Fermentation Experiment Case Study:
    • a) Fermentation is the process of converting sugar into alcohol and carbon dioxide by yeast.
    • b) Temperature affects the rate of fermentation; higher temperatures increase the rate up to an optimum point.
    • c) Yeast is used because it contains enzymes that catalyze the fermentation process.
    • d) By-products: Alcohol and carbon dioxide.