CBSE Class 10 Science Assertion Reason MCQs
CBSE Class 10 Science – Assertion Reason MCQs
Class: 10 | Subject: Science
Section: Exam Oriented
Topic: Assertion & Reason MCQs
Based on Latest CBSE Board Examination Pattern
Section: Exam Oriented
Topic: Assertion & Reason MCQs
Based on Latest CBSE Board Examination Pattern
Each question has two statements — Assertion (A) and Reason (R). Select the correct option:
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.
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.
1. Assertion: Acids conduct electricity.
Reason: They produce ions in aqueous solution.
Reason: They produce ions in aqueous solution.
Answer: A
Acids ionize in water producing H⁺ ions which conduct electricity. Hence R explains A.
Acids ionize in water producing H⁺ ions which conduct electricity. Hence R explains A.
2. Assertion: Rusting is oxidation.
Reason: Iron gains electrons.
Reason: Iron gains electrons.
Answer: C
Rusting is oxidation where iron loses electrons, not gains.
Rusting is oxidation where iron loses electrons, not gains.
3. Assertion: Concave mirror can form real image.
Reason: It is a converging mirror.
Reason: It is a converging mirror.
Answer: A
Concave mirrors converge rays forming real images when object is beyond focus.
Concave mirrors converge rays forming real images when object is beyond focus.
4. Assertion: Plants respire all the time.
Reason: Respiration releases energy.
Reason: Respiration releases energy.
Answer: A
Plants need energy continuously, so respiration occurs day & night.
Plants need energy continuously, so respiration occurs day & night.
5. Assertion: All metals conduct electricity.
Reason: They have free electrons.
Reason: They have free electrons.
Answer: A
Free electrons move under potential difference causing conduction.
Free electrons move under potential difference causing conduction.
6. Assertion: Ozone protects Earth.
Reason: It absorbs UV radiation.
Reason: It absorbs UV radiation.
Answer: A
Ozone layer filters harmful UV rays preventing biological damage.
Ozone layer filters harmful UV rays preventing biological damage.
7. Assertion: Diamond conducts electricity.
Reason: It has free electrons.
Reason: It has free electrons.
Answer: D
Diamond has no free electrons; graphite conducts electricity.
Diamond has no free electrons; graphite conducts electricity.
8. Assertion: Human heart shows double circulation.
Reason: Blood passes twice through heart.
Reason: Blood passes twice through heart.
Answer: A
Pulmonary + systemic circulation together form double circulation.
Pulmonary + systemic circulation together form double circulation.
9. Assertion: Bases turn red litmus blue.
Reason: They release OH⁻ ions.
Reason: They release OH⁻ ions.
Answer: A
Hydroxide ions give basic nature causing indicator change.
Hydroxide ions give basic nature causing indicator change.
10. Assertion: Electric fuse has low melting point.
Reason: It protects circuit.
Reason: It protects circuit.
Answer: A
It melts during overload breaking circuit.
It melts during overload breaking circuit.
11. Photosynthesis needs sunlight / Chlorophyll traps light
A – Correct explanation.
12. Metals are malleable / Layers slide
A.
13. Myopia corrected by concave lens / Diverges light
A.
14. Water is universal solvent / Dissolves many substances
A.
15. Transpiration cools plants / Evaporation causes cooling
A.
16. Alloys resist corrosion / Homogeneous mixture
B – True but not explanation.
17. Refraction occurs in glass / Speed changes
A.
18. ATP is energy currency / Stores energy
A.
19. Coal is fossil fuel / Formed from plants
A.
20. Sound needs medium / Travels via particles
A.