NBSE Question Papers Science Term-1 (Set-1) for Class 10

Class 10  TERM-I SET-1 Series NBSE/X/2021 Code No. 086/10/1 Roll No.  Candidates must write the Code No. on the title page of the OMR sheet. l Please check that this question paper contains 12 printed pages. l Code number given on the right hand side of the question paper should be written on the title page of the OMR sheet. l Please check that this question paper contains 60 questions. l 15 minutes time has been allotted to read this question paper. SCIENCE Time Allowed : 90 Minutes Maximum Marks : 40 General Instructions: 1. The question paper contains three sections. 2. Section A has 24 questions. Attempt any 20 questions. 3. Section B has 24 questions. Attempt any 20 questions. 4. Section C has 12 questions. Attempt any 10 questions. 5. All questions carry equal marks. 6. There is no negative marking. NBSE 2021 1 [P[P.T.T.O.O..

SECTION-A Section — A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 1. To facilitate electrolysis of water we add a few drops of acids like sulphuric acid because (a) it acts as a catalyst (b) it prevents the decomposition of electrodes used (c) it makes the water a good conductor of electricity (d) None of these 2. In an attempt to demonstrate electrical conductivity through an electrolyte, the alongside apparatus was set up. Which among the following statements is/are correct? I. Bulb will not glow because electrolyte is not acidic. II. Bulb will glow because NaOH is a strong base and furnishes ions for conduction. III. Bulb will not glow because circuit is incomplete. IV. Bulb will not glow because it depends upon the type of electrolytic solution. (a) I and III (b) II and IV (c) II only (d) IV only 3. The composition of aqua regia is (a) Dil. HCl : Conc. HCl = 3 : 1 (b) Conc. HCl : Dil. HNO3 = 3 : 1 (c) Conc. HCl : Conc. HNO3 = 3 : 1 (d) Dil. HCl : Dil. HNO3 = 3 : 1 4. A researcher adds barium hydroxide to hydrochloric acid to form a white coloured barium chloride. Which option gives the balanced chemical equation of the reaction? (a) 2HCl + Ba(OH)2 → BaCl2 + O2 + 2H2 (b) 2HCl + Ba(OH)2 → BaCl2 + 2H2O (c) HCl + Ba(OH) → BaOCl + H2 (d) HCl + Ba(OH) → BaCl + H2O 5. The equation shows the reaction of hydrochloric acid with sodium hydroxide HCl + NaOH → NaCl + H2O If the pH of the salt is 7, what are the positive and negative radicals in the salt? (a) Na-negative radical; Cl – negative radical (b) Na-positive radical; Cl – negative radical (c) Na-positive radical; Cl – positive radical (d) Na-negative radical; Cl – positive radical NBSE 2021 2

6. The reaction between iron oxide and hydrogen is given below: Fe3O4 + 4H2 → 3 Fe + 4H2O Which option shows the correct substance which undergo oxidation and reduction? Option Oxidation Reduction (a) H2 Fe3O4 (b) Fe3O4 H2 (c) H2O Fe3O4 (d) Fe H2 7. When crystals of lead nitrate are heated strongly in a dry test tube (a) Crystals immediately melt (b) A brown residue is left (c) White fumes appear in the tube (d) A yellow residue is left 8. An element X on exposure to moist air turns reddish brown and a new compound Y is formed. The substance X and Y are (a) X = Fe, Y = Fe2O3 (b) X = Ag, Y = Ag2S (c) X = Cu, Y = CuO (d) X = Al, Y = Al2O3 9. A student sets up an experiment to study human respiration using lime water, test tube and a straw. The student fills a freshly prepared lime water in a test tube and blows air through the straw into the lime water. It was observed that the solution turns cloudy. What can be evaluated from this observation? (a) Oxygen is exhaled during respiration. (b) Water vapours are produced during respiration. (c) Carbon dioxide is exhaled during respiration. (d) Glucose is produced during respiration. 10. Which of the following gives the correct increasing order of acidic strength? (a) Water < acetic acid < hydrochloric acid (b) Water < hydrochloric acid < acetic acid (c) Acetic acid < water < hydrochloric acid (d) Hydrochloric acid < water < acetic acid 11. Which component is excreted by plants during photosynthesis? (a) Glucose (b) Light energy (c) Carbon dioxide (d) Oxygen 12. What is the likely benefit of a nephron? (a) It helps to keep the output of urine constant throughout the day (b) It helps to uptake and store excess amount of water in the body for later use (c) It makes the process of filtration at bowman's capsule easier (d) It maintains the concentration of urine based on the amount of water present in the body 13. Which option correctly shows the transport of oxygen to the cell? (a) lungs → pulmonary vein → left atrium → left ventricle → aorta → body cells. (b) lungs → pulmonary artery → right atrium → right ventricle → vena cava → body cells. (c) lungs → pulmonary artery → left atrium → left ventricle → vena cava → body cells. (d) lungs → pulmonary vein → right atrium → right ventricle → aorta → body cells. NBSE 2021 3 [P[P.T.T.O.O..

14. From the given picture of the digestive system, identify the labelled organ which has gastric gland. (a) A (b) B (c) C (d) D 15. What prevents backflow of blood inside the heart during contraction? (a) Valves in heart (b) Thick muscular walls of ventricles (c) Thin walls of atria (d) All of these 16. Match the words of column A with that of column B. Column A Column B A. Phloem (i) Excretion B. Nephron (ii) Translocation of food C . Veins (iii) Clotting of blood D. Platelets (iv) Deoxygenated blood (a) A-(ii), B-(i), C-(iv), D-(iii) (b) A-(iii), B-(ii), C-(i), D-(iv) (c) A-(iv), B-(iii), C-(ii), D-(i) (d) A-(i), B-(iv), C-(iii), D-(ii) 17. An object at a distance of 30 cm from a concave mirror gets its image at the same point, focal length of the mirror is (a) –30 cm (b) 30 cm (c) –15 cm (d) 15 cm 18. In the given setup of two prisms, white light enters from prism P1 and the light emits from P2 to the screen is also white light. Which of the following coloured light is represented by X? (a) Violet (b) Red (c) Blue (d) White 19. You are given three media A, B and C of refractive index 1.33, 1.65 and 1.46 respectively. The medium in which the light will travel faster is (a) A (b) B (c) C (d) Equal in all media NBSE 2021 4

20. White light passes through an equilateral prism then (a) Dispersion takes place at first refracting surface and refraction at second refracting surface. (b) Refraction takes place at first refracting surface and dispersion at second refracting surface. (c) Dispersion takes place at both refracting surface. (d) Refraction takes place at both refracting surface. 21. A student studies that convex mirror always forms virtual image irrespective of its position. What causes the convex mirror to always form a virtual image? (a) Because the reflected ray never intersect. (b) Because the incident ray traces its path back along the principal axis. (c) Because the incident ray of a convex mirror gets absorbed in the mirror. (d) Because the reflected ray converges at a single point. 22. The path of a ray of light coming from air passing through a rectangular glass slab traced by four students are shown as A, B, C and D in figure. Which one of them is correct? (A) (B) (C) (D) (a) A (b) B (c) C (d) D 23. Which of the following gases can be used for storage of fresh sample of an oil for a long time? (a) Carbon dioxide or oxygen (b) Nitrogen or oxygen (c) Carbon dioxide or helium (d) Helium or nitrogen 24. A beam of light is incident through the holes on side A and emerges out of the hole on the other face of the box as shown in the figure. Which of the following could be inside the box? (a) Concave lens (b) Rectangular glass slab (c) Prism (d) Convex lens SECTION-B Section — B consists of 24 questions (Sl. No. 25 to 48). Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 25. Which of the following statements is correct about an aqueous solution of an acid and or a base? (i) Higher the pH, stronger the acid (ii) Higher the pH, weaker the acid (iii) Lower the pH, stronger the acid (iv) Lower the pH, weaker the acid (a) (i) and (iii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv) NBSE 2021 5 [P[P.T.T.O.O..

26. Which one of the following properties is not generally exhibited by ionic compound? (a) Solubility in water (b) Electrical conductivity in solid state (c) High melting and boiling points (d) Electrical conductivity in molten state 27. Which compound is formed in the chemical reaction between a small strip of magnesium and nitric acid? (a) MgNO3 and H2O (b) Mg(NO3)2 and H2O (c) Mg(NO3)2 and H2 (d) MgNO3 and H2 28. CaOCl2 will liberate Cl2 gas in presence of (i) CO2 (ii) HCl (iii) CO (iv) NO (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (ii) and (iv) 29. Common salt besides being used in kitchen can also be used as the raw material for making (i) Washing soda (ii) Bleaching powder (iii) Baking soda (iv) Slaked lime (a) (i) and (ii) (b) (i), (ii) and (iv) (c) (i) and (iii) (d) (i), (iii) and (iv) 30. The image represents the position of an object corresponding to a convex lens. Where is the image most likely to form? (a) Position P (b) Position Q (c) At F2 (d) Position R Question No. 31 to 34 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. 31. Assertion (A): After white washing the walls, a shiny white finish on walls is obtained after two to three days. Reason (R): Calcium oxide reacts with carbon dioxide to form calcium hydrogen carbonate which gives shiny white finish. 32. Assertion (A): In woody plants, gaseous exchange occurs through lenticels. Reason(R): Lenticels are specialised cells found along with stomata on the stem of woody plants. 33. Assertion (A): Sodium metal is stored under kerosene. Reason (R): Metallic sodium melts when exposed to air. 34. Assertion (A): A white light on passing through prism splits into its component colours such that the red light emerges nearest to the base of the prism. Reason (R): Wavelength of red light is more than other component colours and hence, red light deviates least. NBSE 2021 6

35. In which of the following groups of organisms, food material is broken down outside the body and absorbed? (a) Mushroom, green plants, Amoeba (b) Yeast, mushroom, bread mould (c) Paramecium, amoeba, Cuscuta (d) Cuscuta, lice, tapeworm. 36. Each nephron has a cup shaped upper end called ____, which contains a_____ (a) Bowman’s capsule, Ampulla (b) Capillaries, Bowman’s capsule (c) Ampulla, Glomerulus (d) Bowman’s capsule, Glomerulus 37. A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four student A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant building is obtained almost immediately on it. Which of the following students suggests the correct position of image? Option Student Position of Image (a) A 12.7 cm (b) B 27.7 cm (c) C 57.7 cm (d) D 72.7 cm 38. Which of the following statements is true? (a) A convex lens has 4 dioptre power having a focal length of 0.25 m. (b) A convex lens has –4 dioptre power having a focal length of 0.25 m. (c) A concave lens has 4 dioptre power having a focal length of 0.25 m. (d) A concave lens has –4 dioptre power having a focal length of 0.25 m. 39. In the figure given below, the structures associated with human kidneys are marked (X,Y and Z ). The relative concentrations of urea in these structures is (a) X is sometimes higher than Y (b) Y is always higher than Z [P.T.O. (c) Y is always lower than Z (d) Z is sometimes lower than X NBSE 2021 7

40. In order to obtain a magnification of –0.6(minus 0.6) with a concave mirror, the object must be placed (a) At the focus (b) Between pole and focus (c) Between focus and centre of curvature (d) Beyond the centre of curvature 41. Sunil conducts an activity using an object of height 10 cm and a convex mirror of focal length 20 cm. He placed the object at a distance of 20 cm in front of the mirror. What is likely to be height of the image produced? (a) 15 cm (b) 5 cm (c) 1 cm (d) 20 cm 42. Four students were asked to study the reaction between solution of BaCl2 and sodium sulphate. On mixing the solutions of the two salts in a test tube, they reported their experiments as follows: (a) The colour of mixture became brown (b) The solution forms separate layers (c) A colourless mixture is obtained (d) A white substance settles at the bottom 43. The refractive index of water is 1.33. The speed of light in water will be (a) 1.33 × 108 m/s (b) 3 × 108 m/s (c) 2.26 × 108 m/s (d) 2.66 ×108 m/s 44. While performing an experiment on determination of focal length of a convex lens, four students obtained the image of the same distant tree on the screen as follows: (A) (B) (C) (D) (d) D Which diagram shows the formation of image correctly? (a) A (b) B (c) C NBSE 2021 8

45. A basic solution is added to a test tube. A blue and red litmus paper is dipped into the basic solution. What will happen to both litmus papers? (a) Blue litmus paper: changes colour ; red litmus paper: no colour change (b) Blue litmus paper: changes colour ; red litmus paper: changes colour (c) Blue litmus paper: no colour change ; red litmus paper: changes colour (d) Blue litmus paper: no colour change; red litmus paper: no colour change 46. An experiment is set up as shown. Flasks 1 and 2 contain lime water. Air is pumped through the flasks. What is the appearance of lime water in flasks 1 and 2 after a period of ten minutes? Option Flask 1 Flask 2 (a) White White (b) White Clear (c) Clear White (d) Clear Clear 47. Refractive index of a substance (a) depends on the wavelength of light used (b) is the sole property of the substance (c) depends on the angle of incidence of light (d) None of these 48. In each test tubes A, B, C and D, 2 mL of aqueous solution of Al2(SO4)3 was filled. Clean pieces of zinc was placed in test tube A, clean iron nail was put in test tube B, silver (Ag) was placed in test tube C and a clean copper wire was placed in test tube D. Al2(SO4)3 + Zn Al2(SO4)3 + Fe Al2(SO4)3 + Ag Al2(SO4)3 + Cu (A) (B) (C) (D) Which of the following change observed in test tubes correct? (a) Solution turns light green in test tube B. (b) Solution turns white from colourless in test tube A. (c) Solution turns blue in test tube D. (d) No change is observed in test tubes A, B, C and D. NBSE 2021 9 [P.T.O.

SECTION-C Section – C consists of three Cases followed by questions. There are a total of 12 questions in this section. Attempt any 10 questions from this section. The first attempted 10 questions would be evaluated. Case I. Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety of structures, from hand-held sculptures to massive pillars and buildings. 49. The substance not likely to contain CaCO3 is (a) Dolomite (b) A marble statue (c) Calcined gypsum (d) Sea shells. 50. A student added 10g of calcium carbonate in a rigid container, secured it tightly and started to heat it. After some time, an increase in pressure was observed due to release of gas ‘A’, the pressure reading was then noted at intervals of 5 mins and plotted against time, in a graph as shown below. During which time interval did maximum decomposition took place? 0 5 10 15 Time (min) (a) 15-20 min (b) 10-15 min (c) 5-10 min (d) 0-5 min 51. Gas A, obtained above is a reactant for a very important biochemical process which occurs in the presence of sunlight. Identify the name of the process. (a) Respiration (b) Photosynthesis (c) Transpiration (d) Sphotolysis NBSE 2021 10

52. Calcium oxide can be reduced to calcium, by heating with sodium metal. Which compound would act as an oxidizing agent in the above process? (a) Sodium (b) Sodium oxide (c) Calcium (d) Calcium oxide Case II. Energy is needed to maintain a state Green spots of order in our body. The source of energy and materials is the food we Blue- eat. Some organisms use simple food black materials obtained from inorganic sources and other organisms utilize complex substances. These complex substances have to be broken down into simpler ones before they can be used for the upkeep and growth of the body. Plants prepare their food by photosynthesis. A student (i) (ii) performs an experiment to verify the need Variegated leaf (i) before and (ii) after starch test of carbon dioxide for photosynthesis. The student observed the leaf before and after the experiment as shown above. 53. All non green organisms fall under the category of (a) Autotrophs (b) Heterotrophs (c) Saprotrophs (d) Chemotrophs 54. During the test performed on the leaf as described in the passage the solution used to absorb CO2 is (b) Ethyl alcohol (a) Potassium hydroxide (c) Potassium iodide (d) Iodine 55. The diagram given below represents the cross section of a leaf X Identify X and choose the correct combination of information provided in the following. X Description Function (a) Chlorophyll A green coloured pigment Essential for photosynthesis (b) Chloroplast A cell organelle Conducts photosynthesis (c) Vascular bundle Vascular tissue Transportation in plants (d) Chloroplast A green coloured pigment Essential for photosynthesis NBSE 2021 11 [P.T.O.

56. Study the table given below and select the row that has the incorrect information. Organism Type of heterotrophic nutrition (a) Amoeba Holozoic (b) Mushroom Saprophytic (c) Lice Parasitic (d) Lion Parasitic Case III. A student did an experiment with a convex lens. He puts an object at different distances from the lens. In each case he measured the distance of the image from the lens. A part of his results is recorded in the following table: Object distance 25 30 40 60 120 Image distance 100 60 40 30 24 After comparing his results, he observed when the object shifts from –∞ to F1, the image moves from F2 to +∞. And when the object shifts from F1 to O, the image moves from –∞ to O. 57. The focal length of the lens is (a) 20 cm (b) 25 cm (c) 30 cm (d) 35 cm 58. Where should an object be placed in front of a convex lens to get a real image of the size of the object? (a) At the principal focus of the lens (b) At twice the focal length (c) At infinity (d) Between the optical centre of the lens and its principal focus. 59. Which of this object distances gives the biggest image (a) 30 cm (b) 25 cm (c) 40 cm (d) 60 cm 60. The minimum distance between an object and its real image formed by a convex lens is (a) 2f (b) 3f (c) 4f (d) zero NBSE 2021 12