Title Science-A.pdf ✅

1 HALF YEARLY EXAM (2022-23) CLASS: X SUBJECT: SCIENCE (SET-A) Time : 3 Hours M.M.: 80 General Instructions: 1. This question paper contains 46 questions. 2. Paper divided into four sections A, B, C & D. 3. All questions are compulsory ________________________________________________________________________________ SECTION-A Q1. Why should a chemical equation be balanced? 1C Q2. Give any two observations which proves that heating of lead nitrate is a chemical change. 1C Q3. Why does HCl gas not change colour of dry blue litmus paper. 1C Q4. Give any one use of POP. 1C Q5. Why olfactory indicators can be used by visually impaired students. 1C Q6. Why Excretion is important for every living organism? 1B Q7. Rate of respiration is more in aquatic organisms as compared to terrestrial organisms. Give reason. 1B Q8. How is lymph different from blood? (Any two points) 1B Q9. Name the blood vessels which transfers blood from heart to lungs and vice versa . 1B Q10. Ventricles are thick walled than auricles. Give reason. 1B Q11. Define 1 dioptre of power of a lens. 1P Q12. Why does a ray of light bend from its path when it travels from one medium to another? 1P Q13. Neha visited a dentist in his clinic. She observed that the dentist was holding an Instrument fitted with a mirror. State the nature of this mirror and reason for its use in the Instrument used by dentist. 1P Q14. What is function of iris in the human eye? 1P Q15. List the factors on which scattering of light depends? 1P ASSERTION-REASON BASED QUESTIONS The following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below: A. Both A and R are true and R is the correct explanation of A B. Both A and R are true and R is not the correct explanation of A C. A is true but R is false D. A is False but R is true Q16. Assertion(A): After whitewashing the walls, a shiny white finish on walls is obtained after two to three days. 1C REASON(R): Calcium Oxide reacts with Carbon dioxide to produce Calcium Carbonate which gives shiny white finish. Q17. Assertion(A): Gas bubbles are observed when sodium carbonate is added in dilute hydrochloric acid. REASON(R): Carbon dioxide is given off in the reaction. 1C Q18. Assertion: A synapse helps in transfer of messages from axon end to next dendrite. Reason: Synapse is present as a gap in between two adjacent neurons. 1B Q19. Assertion(A): A gaseous element Hydrogen is given a position in the reactivity series of metals. Reason(R): Hydrogen atom can lose electron to form cation. 1C Q20. Assertion (A)- A prism causes dispersion of light but a rectangular glass slab doesn’t cause
2 dispersion of light. Reason(R) - Dispersion of light is the phenomenon of splitting of a beam of white light into its constituent colours. 1P OR Assertion (A) – power of a lens is inversely proportional to its focal length. Reason (R) – power of a convex lens is having positive sign and that of a concave lens is negative. Q21. CuSO4 + H2S → CuS + H2SO4 1C The type of chemical reaction is a) Combination b) Decomposition c) Displacement d) Double Displacement Q22. The longest fibre on the cell body of a neuron is called 1B (a) sheath (b) cytoplasm (c) axon (d) dendrites Q23. Pb + H2O2→PbO + H2O The substance oxidised and substance reduced in the above equation are as follows: 1C a) Pb,H2O2 b) H2O2, PbO c) PbO,H2O d) Pb,H2O Q24. Which of the following indicator will not appear red in HCl: 1C (A) Blue litmus (B) Red Litmus (C) Methyl Orange (D) Phenolphthalein Q25. The highest coordinating centre in the human body is 1B (a) spinal cord (b) heart (c) brain (d) kidney Q26. Which option correctly shows the order of events when we touch a hot object? 1B (a) Hot object → receptors in skin → sensory neuron → motor neurons → pull the hand away (b) Hot object → receptors in skin → spinal cord → sensory neuron → motor neurons → pull the hand away (c) Hot object → receptors in skin → sensory neuron → spinal cord → motor neurons →pull the hand away (d) Hot object → receptors in skin → spinal cord → sensory neuron → pull the hand away Q27. Identify the picture shown 1B (a) Neuromuscular junction (b) Neuron (c) Muscle fibre (d) Reflex arc Q28. Which of the following statements is correct about receptors? 1B (a) Gustatory receptors detect taste while olfactory receptors detect smell (b) Both gustatory and olfactory receptors detect smell
3 (c) Auditory receptors detect smell and olfactory receptors detect taste (d) Olfactory receptors detect taste and gustatory receptors smell Q29. Under which of the following conditions a concave mirror can form a real and inverted image larger than the actual object? 1P a. when object is kept at center of curvature of the mirror. b. when object is kept at a distance less than its focal length. c. when object is placed at principal focus of the mirror. d. when object is placed between its focus point and centre of curvature. Q30. An astronaut lands his spacecraft on the surface of moon and observes the sky. He will find the colour of sky as 1P a. deep blue b. light blue c. white d.black Q31. Refraction of light while passing through earth’s atmosphere of varying optical density is known as 1P a. optical refraction b. atmospheric refraction c. atmospheric dispersion d. Tyndall effect Q32. An optical device forms an erect image of an object placed in front of it. If the size of the image is one half of the object, the optical device is a: 1P a. concave mirror b. convex mirror c. plane mirror d. convex lens CASE STUDY BASED QUESTIONS Q33. Read the following passage and answer the questions from (i) to (iv): (1X4= 4)C In chemistry, a salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions, which results in a compound with no net electric charge. A common example is table salt, with positively charged sodium ions and negatively charged chloride ions. (i) The gases evolved at cathode and anode during electrolysis of aqueous solution of common salt in water are as respectively 1 (a) H2, Cl2 (b) H2, O2 (c) Cl2, H2 (d) O2, Cl2 (ii) Which of the following statement is wrong regarding baking soda. 1 (a) Baking soda is sodium hydrogen carbonate. (b) On heating baking soda, it gives sodium carbonate. (c) It is used in the preparation of soap. (d) It is an ingredient in baking powder. (iii) Identify the basic salt from the following salts: 1 (a) Na2CO3 (b) NH4Cl (c) NaNO3 (d) KCl (iv) Which of the following salts does not contain water of crystallisation? 1 (a) blue vitriol (b) Baking soda (c) Washing soda (d) Gypsum
4 Q34. Read the following passage and answer the questions from (i) to (iv): (1X4= 4) B Double circulation is a type of circulating system in which the blood passes through the heart twice before completing a full circuit of the body. Blood is pumped from the heart to the lungs and returns to the heart before being distributed to other organs and tissues of the body. (i) The given figure is of circulatory system. Identify the labelled parts (A-D) from the list (I-VII). (I) Pulmonary circulation (II) Systemic circulation (III) Superior vena cava (IV) Inferior vena cava (V) Aorta (VI) Veins and venules (VII)Arterioles and capillaries (a) A-(V), B-(lII), C-(I), D-(VII) (b) A-(VII), B-(IV), C-(I), D-(VI) (c) A-(V), B-(III), C-(lI), D-(VII) (d) A-(VII), B-(V), C- (I), D-(VI) (ii) The blood vessel which carries blood from Left Ventricle to body parts (a) Vena cava (b) Aorta (c) Pulmonary vein (d) Pulmonary artery (iii) Incomplete double circulation is seen in (a) mammals (b) pisces (c) aves (d) amphibians. (iv) Which of the following animals shows double circulatory pathway? (a) Snake (b) Frog (c) Eel (d) Whale Q35. Read the following passage and answer the questions from (i) to (iv): (1x4 = 4)B Transpiration is the evaporative loss of water by plants. It occurs mainly through the stoma in the leaves. Besides the loss of water vapour in transpiration, exchange of oxygen and carbon dioxide in the leaf also occurs through pores called stomata. Normally stomata remain open in the day time and close during the night (i) Which of the following will not directly affect transpiration? (a) Temperature (b) Light (c) Wind speed (d) Chlorophyll content of leaves (ii) Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening, carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of following options. (a) The above processes happen only during night time. (b) One process occurs during day time and the other at night. (c) Both processes cannot happen Simultaneously. (d) Both processes can happen together at day time. (iii) Which of the following statements is not true for stomatal apparatus? (a) Guard cells invariably possess chloroplasts and mitochondria. (b) Guard cells are always surrounded by epidermal cells. (c) Stomata are always involved in gaseous exchange. (d) Guard cells do not have cell wall.