Class 10 Science
Previous Board Examination – Full Solved Answers (Set 1)
All answers are written in simple student exam-writing style, strictly following CBSE board valuation norms.
Section A – MCQs (Answers)
1. Wind
2. 7
3. –OH
4. Ampere
5. O
Section B – Very Short Answer
6. Define electric current.
Electric current is the flow of electric charge per unit time through a conductor.
7. What is meant by corrosion?
Corrosion is the slow destruction of metals by chemical reaction with air, moisture or acids.
8. Name the pigment responsible for photosynthesis.
Chlorophyll
9. Write the chemical formula of washing soda.
Na2CO3·10H2O
10. What is the function of alveoli?
Alveoli help in the exchange of oxygen and carbon dioxide between blood and air.
Section C – Short Answer
11. State Ohm’s Law.
Ohm’s Law states that at constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends.
V ∝ I or V = IR
12. What is homologous series? Give one example.
A homologous series is a group of organic compounds having the same functional group and similar chemical properties.
Example: Alkanes – CH4, C2H6
13. Explain the process of transpiration.
Transpiration is the loss of water in the form of water vapour from the aerial parts of plants, mainly through stomata.
14. Write any three properties of acids.
1. Acids have a sour taste.
2. They turn blue litmus red.
3. They produce hydrogen gas with metals.
15. What is double circulation? Why is it important?
Double circulation is the circulation of blood twice through the heart in one complete cycle.
It is important because it ensures proper separation of oxygenated and deoxygenated blood.
16. Define refraction of light. Give one example.
Refraction is the bending of light when it passes from one medium to another.
Example: A pencil appears bent in water.
Section D – Long Answer
17. Explain the process of electrolysis.
Electrolysis is the process of decomposition of an electrolyte by passing electric current through it.
When electric current is passed through water, it breaks into hydrogen and oxygen gases.
18. Describe the extraction of metals from their ores.
Extraction of metals involves concentration of ore, roasting or calcination, and reduction.
Highly reactive metals are extracted by electrolysis, while less reactive metals are extracted using carbon.
19. Explain the human heart.
The human heart is a muscular organ with four chambers – two atria and two ventricles.
It pumps oxygenated blood to the body and deoxygenated blood to the lungs.
20. State and explain the laws of reflection of light.
1. The angle of incidence is equal to the angle of reflection.
2. The incident ray, reflected ray and the normal lie in the same plane.
Section E – Case Study Based
21.
a) Rusting
b) Presence of air and moisture
c) Painting and galvanization
Shaktimatha CBSE Learning
Class 10 Science – Previous Board Exam Full Answers (Set 1)
⬅️ Back to Class 10 Science Library
🔬 Class 10 Science – Previous Board Question Papers & Full Answers
This complete library is designed for Class 10 CBSE students to practise previous board exam papers and learn how to write perfect answers in Physics, Chemistry, and Biology.
📝 Previous Board Question Papers
- Question Paper – Set 1
- Question Paper – Set 2
- Question Paper – Set 3
- Question Paper – Set 4
- Question Paper – Set 5
✍️ Full Answers (Student Writing Style)
- Full Answers – Set 1
- Full Answers – Set 2
- Full Answers – Set 3
- Full Answers – Set 4
- Full Answers – Set 5
📚 Additional Board Sets (Practice)
- Additional Question Paper – Set 1A
- Additional Full Answers – Set 1A
- Additional Question Paper – Set 2A
- Additional Full Answers – Set 2A
- Additional Question Paper – Set 3A
- Additional Full Answers – Set 3A
✔ First attempt the question paper on your own
✔ Then compare with full answers
✔ Observe diagrams, keywords, and steps
✔ Practise again to improve speed and accuracy
Prepared with dedication by Shaktimatha Learning ✨
Clear concepts • Exam confidence • Board success
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