X Sci 2

CBSE CLASS X SCIENCE

MODEL QUESTION PAPER - 2

Class: X	Academic Session: 2026-27
Subject: Science (Ch: 1, 2, 3, 5, 6, 9, 10, 11)	Time Allowed: 1.5 Hours
Coverage: Physics, Chemistry, Biology	Max. Marks: 40

SECTION A: MULTIPLE CHOICE QUESTIONS [10 MARKS]

Q1. Which of the following is an example of a thermal decomposition reaction? [1]

(A) Electrolysis of water

(B) Heating of ferrous sulphate crystals

(C) Burning of natural gas

(D) Digestion of food in body

Q2. What is the nature of an aqueous solution having a pH value of 3? [1]

(A) Strongly basic

(B) Neutral

(C) Strongly acidic

(D) Weakly acidic

Q3. Which of the following non-metals is a liquid at room temperature? [1]

(A) Iodine

(B) Carbon

(C) Bromine

(D) Phosphorus

Q4. Nitrogenous waste products like urea and uric acid are removed from blood in humans by: [1]

(A) Lungs

(B) Kidneys

(C) Liver

(D) Small Intestine

Q5. Wilting of leaves in plants is caused by the hormone: [1]

(A) Gibberellin

(B) Auxin

(C) Abscisic Acid

(D) Cytokinin

Q6. The image formed by a concave mirror is observed to be virtual, erect, and larger than the object. Where should the object be placed? [1]

(A) At the focus

(B) Between focus and pole

(C) Beyond the center of curvature

(D) At center of curvature

Q7. Which color of light suffers the maximum deviation while passing through a glass prism? [1]

(A) Red

(B) Violet

(C) Yellow

(D) Green

Q8. Hypermetropia is corrected by using a lens of suitable: [1]

(A) Concave nature

(B) Convex nature

(C) Bifocal nature

(D) Cylindrical nature

Q9. What is the power of a convex lens of focal length 0.5 m? [1]

(A) +2.0 D

(B) −2.0 D

(C) +0.5 D

(D) −0.5 D

Q10. Which of the following oxides is amphoteric in nature? [1]

(A) Na₂O

(B) MgO

(C) Al₂O₃

(D) SO₂

SECTION B: FILL IN THE BLANKS [10 MARKS]

Q11. Rusting of iron is an example of ____________________ reaction. [1]

Q12. The chemical formula of Plaster of Paris is ____________________. [1]

Q13. Metals react with oxygen to form ____________________ oxides. [1]

Q14. The green pigment in leaves essential for photosynthesis is called ____________________. [1]

Q15. The structural unit of human nervous system is the ____________________. [1]

Q16. The center of the reflecting surface of a spherical mirror is called its ____________________. [1]

Q17. Lens formula relates object distance (u), image distance (v), and focal length (f) as ____________________. [1]

Q18. Advanced sunrise and delayed sunset occur due to atmospheric ____________________. [1]

Q19. The part of human eye that controls the amount of light entering it is the ____________________. [1]

Q20. The gland that secretes insulin to regulate blood sugar levels is the ____________________. [1]

SECTION C: SHORT ANSWER QUESTIONS [10 MARKS]

Q21. What is a redox reaction? Identify the substance oxidized and reduced in: CuO + H₂ → Cu + H₂O. [2]

Q22. Why does distilled water not conduct electricity, whereas rainwater does? [2]

Q23. Mention two differences between aerobic and anaerobic respiration. [2]

Q24. An object is placed 10 cm in front of a concave mirror of focal length 15 cm. Find the position of the image. [2]

Q25. What is Tyndall effect? Give one practical example observed in daily life. [2]

SECTION D: LONG ANSWER & CASE STUDY QUESTIONS [10 MARKS]

Q26. [5]
(a) Draw a ray diagram showing refraction of light through a convex lens when object is placed between F₁ and 2F₁.
(b) A concave lens has focal length of 15 cm. At what distance should an object be placed so that it forms an image at 10 cm from the lens?
(c) Calculate the magnification produced by the lens.

Q27. CASE STUDY BASED QUESTION: [5]

Read the passage given below and answer the questions that follow:

Coordination in human beings is carried out by both nervous system and endocrine system. While nervous signals travel as electrical impulses along neurons providing rapid control, chemical regulation via hormones released by endocrine glands offers prolonged metabolic control over growth, development, and balance.

Sub-questions:
(a) Which part of the human brain maintains posture and equilibrium of the body? [1]
(b) Name the hormone responsible for secondary sexual changes in human males and the gland that secretes it. [1]
(c) Explain reflex arc with a simple sequence showing how hand is pulled back upon touching a hot object. [3]

ANSWER KEY & MARKING SCHEME

SECTION A: MCQs

Q. No.	Correct Answer	Q. No.	Correct Answer
Q1	(B) Heating of ferrous sulphate crystals	Q6	(B) Between focus and pole
Q2	(C) Strongly acidic	Q7	(B) Violet
Q3	(C) Bromine	Q8	(B) Convex nature
Q4	(B) Kidneys	Q9	(A) +2.0 D
Q5	(C) Abscisic Acid	Q10	(C) Al2O3

SECTION B: Fill in the Blanks

Q. No.	Answer	Q. No.	Answer
Q11	Oxidation / Corrosion	Q16	Pole
Q12	CaSO4·½H2O	Q17	1/f = 1/v − 1/u
Q13	Basic	Q18	Refraction
Q14	Chlorophyll	Q19	Iris / Pupil
Q15	Neuron	Q20	Pancreas

SECTION C: Short Answers (2 Marks Each)

Q21: A reaction in which oxidation and reduction occur simultaneously. Oxidized: H₂; Reduced: CuO. (1 mark definition, 1 mark identification)

Q22: Distilled water has no dissolved salts/ions to carry charge. Rainwater contains dissolved gases (CO₂, SO₂) forming acids that release free ions. (2 marks)

Q23: Aerobic: takes place in presence of O₂, produces CO₂, water, and 38 ATP. Anaerobic: takes place without O₂, produces ethanol/lactic acid and 2 ATP. (2 marks)

Q24: Mirror formula: 1/f = 1/v + 1/u ⇒ 1/(−15) = 1/v + 1/(−10) ⇒ 1/v = 1/10 − 1/15 = 1/30. Image distance v = +30 cm (Virtual image formed behind mirror). (2 marks)

Q25: Scattering of light beam by colloidal particles making its path visible. Example: Sunlight passing through a dense canopy of forest / dusty room. (2 marks)

SECTION D: Long Answer & Case Study (5 Marks Each)

Q26: (a) Ray diagram description: Real, inverted, magnified image formed beyond 2F₂. (2 marks)
(b) Given f = −15 cm, v = −10 cm. Using 1/f = 1/v − 1/u ⇒ 1/(−15) = 1/(−10) − 1/u ⇒ 1/u = −1/10 + 1/15 = −1/30 ⇒ u = −30 cm. Object distance = 30 cm. (2 marks)
(c) Magnification m = v / u = (−10) / (−30) = +0.33. (1 mark)

Q27: (a) Cerebellum. (1 mark)
(b) Testosterone, secreted by Testes. (1 mark)
(c) Reflex Arc Sequence: Receptor (Skin) → Sensory Neuron → Spinal Cord (Relay Neuron) → Motor Neuron → Effector (Arm Muscle) → Muscle Withdrawal. (3 marks)