Subject: Science
Class X
Time Allowed: 3 hours
Max. Marks: 80
General Instructions:
The question paper comprises of five sections A, B, C, D and E. There are 46 questions in the question paper. All questions are compulsory.
Section A -Question number 1 to 32 are of one mark each. These questions contain very short answer questions, multiple choice questions and assertion reason questions.
Section B-Question number 33to36 are case based questions. Each question carries four marks. Answer any four questions out of the five questions given for each case study.
Section C-Question number37 to 40 are of two marks each.
Section D-Question number 41 to 43 are three marks each.
Section E-Question number 44 to 46 are five marks each.
Section – A
1. Name the tissue which transports soluble products of photosynthesis in a plant.
2. The image shows the structure of an artery.
Which statement clearly expresses the reason for thick walls in arteries?
a) to carry large amount of blood
b) to allow easy exchange of gases with cells
c) to ensure blood flows in only one direction
d) to sustain the high pressure of blood from the heart
3. A student sets up an experiment to study the role of enzymes in digestion of food.
In which test tube, the digestion of protein will occur?
a) Test tube A as pepsin will break down into simple molecules
b) Test tube B as HCl will breakdown protein into simple molecules.
c) Test tubes A as pepsin will breakdown protein into simple molecules.
d) Test tube B as HCl will activate pepsin for breakdown of protein into simple molecules.
4. Oxygen liberated during photosynthesis comes from
a) Water
b) Chlorophyll
c) Carbon dioxide
d) Glucose
5. Choose the event that does not occur in photosynthesis
a) Absorption of light energy by chlorophyll
b) Reduction of carbon dioxide to carbohydrate
c) Oxidation of carbon to carbon dioxide
d) Conversion of light energy to chemical energy
6. Nephron is a unit of filtration in kidneys that filters waste material. It selectively reabsorbs water with the help of capillaries that surround it. What is the likely benefit of this?
a) It makes the process of filtration at Bowman’s capsule easier.
b) It helps keep the output of urine constant throughout the day.
c) It helps to uptake and store excess amounts of water in the body for later use
d) It maintains the concentration of urine based on the amount of water present in the body.
7. Find the angle of incidence and angle of reflection from the diagram given below.
8. The refractive index of dense flint glass is 1.65 and for alcohol it is 1.36 with respect to air. What is the refractive index of the dense flint glass with respect to alcohol?
9. The Rays from Sun converge at a point 9 cm behind the convex lens. Where should an object be placed so that size of its image is equal to the size of the object?
10. When an object is kept at finite distance from concave lens, a diminished image is formed in front of the lens. The image is
a) Real and erect
b) Real and inverted
c) Virtual and inverted
d) Virtual and erect
11. Which of the following is NOT an exothermic process?
a) Reaction of water with quick lime
b) Dilution of an acid.
c) Decomposition of vegetable matter into compost
d) Sublimation of Naphthalene
12. An aqueous solution turns red litmus solution blue. Excess addition of which of the following solution can reverse the change?
a) Baking soda
b) Vinegar
c) Washing soda
d) Lime water
13. Reema took 5 ml of Lead Nitrate solution in a beaker and added approximately 4ml of Potassium iodide solution to it. What would she observe?
a) The solution turned red.
b) Yellow precipitate was formed.
c) White precipitate was formed.
d) The reaction mixture became hot.
14. Vinay observed that the stain of curry on a white shirt becomes reddish brown when soap is scrubbed on it, but it turns yellow again when the shirt is washed with plenty of water. What might be the reason for his observation?
i. Soap is acidic in nature
ii. Soap is basic in nature
iii. Turmeric is a natural indicator which gives reddish tinge in bases
iv. Turmeric is a natural indicator which gives reddish tinge in acids.
a) i and ii
b) ii and iii
c) i and iv
d) ii and iv
15. During the preparation of hydrogen chloride gas on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to
a) absorb the evolved gas
b) moisten the gas
c) absorb moisture from the gas
d) absorb chloride ions from the evolved gas
16. How will you protect yourself from the heat generated while diluting a concentrated acid?
a) By adding acid to water with constant stirring
b) By adding water to acid with constant stirring
c) By adding water to acid followed by base
d) By adding base to acid with constant stirring.
17. Name the following
a) An enzyme secreted from gastric glands in stomach that acts on proteins
b) Cells that surround a stomatal pole.
18. What is the advantage of having a four chambered heart?
Direction: In the question number 19 to 24, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
b) Both the Assertion and the Reason are correct and the Reason is the not the correct explanation of the Assertion.
c) Assertion is true but the Reason is false
d) The statement of the Assertion is false but the Reason is true
19. Assertion: Simple diffusion cannot meet requirements of all the cells in multicellular organisms.
Reason: All cells present in the body of multicellular organisms are not in direct contact with the surrounding environment.
20. Assertion: Pyruvate is a 4 carbon compound
Reason: It is formed in the cytoplasm as the first step of cellular respiration.
21. Assertion: Sky predominantly appears light blue on account of scattering of light.
Reason: Wavelength of blue is least.
22. Assertion: A rainbow formed in sky usually after a rain shower is a natural example of the spectrum of white light.
Reason: Tiny water droplets hanging in atmosphere act like tiny prism and from spectrum due to reflection, dispersion and internal reflection of light.
24. Assertion: pH of ammonium chloride solution is less than 7.
Reason: Solution of a salt of weak base and strong acid is acidic.
24. Assertion: Copper sulphate crystals are wet because it contains water of crystallisation.
Reason: Water of crystallisation is the fixed number of molecules of water present in one formula unit of salt.
25. Why is transpiration important for plants.
26. In the reaction of: MnO2 + 4HCl — > MnCl2 + 2H2O + Cl2 Which option in the given table correctly represents the substance oxidised and the reducing agent.
| Option | Substance Oxidized | Reducing Agent |
| a | MnO2 | MnCl2 |
| b | HCl | HCl |
| c | Cl2 | MnO2 |
| d | HCl | Cl2 |
27. Which of the following statements is INCORRECT?
a) Bleaching powder is used in removal of hardness in water.
b) Baking soda is used as antacid
c) Common salt can be used in preparation of hydrogen and chlorine
d) Plaster of Paris is used in setting of fractured bones.
28. The refractive index of transparent medium is greater than one because
a) speed of light in vacuum < speed of light in transparent medium
b) speed of light in vacuum >speed of light in transparent medium
c) speed of light in vacuum = speed of light in transparent medium
d) frequency of light waves changes when t moves from rarer to denser medium
29. The correct sequencing of angle of incidence, angle of emergence, angle of refraction and lateral displacement shown in the following diagram by digits 1, 2, 3 and 4 is
a) 2,4,1,3
b) 2,1,4,3
c) 1,2,4,3
d) 2,1,3,4
30. due to atmospheric refraction of sunlight, the time from sunrise to sunset is lengthened by about:
a) 6 min
b) 5 min
c) 2 min
d) 4 min
31. Rewrite the following equation in balanced form
Pb(NO3)2 — > PbO + NO2 + O2
32. Electrolysis of water is a decomposition reaction. What is the ratio of volume of hydrogen to oxygen gas liberated during this reaction?
Section – B
Case study-based questions. Do any four question out of five
33. Abhilasha, a student of Class IX loves to eat street food from the hawkers. One day, she developed a mild fever with pain in the abdomen and loss of appetite. When taken to the doctor, she was prescribed certain tests. The test results indicated that she was suffering from Hepatitis A. the doctor advised her to take a lot of fruit juices and a low-fat diet as her body cannot digest fat properly.
a) Which organ of her body is affected in this disease?
i) Liver
ii) Pancreas
iii) Spleen
iv) Stomach
b) Name the juice secreted by this organ?
c) What are the functions of the juice secreted by this organ?
d) In which part of the alimentary canal, digestion of food is affected?
e) Name the enzyme responsible for digestion of fat.
34. The pH of a solution is a measure of its hydrogen ion (H+) concentration. Itis measured generally using pH scale. The values on pH scale ranges from 0 to 14. A pH of 1 is very acidic and corresponds to a high concentration of H ions. A pH of 14 is very basic and corresponds to a low concentration of H ions. The pH of a neutral solution is 7.
The pH value of three substances is given below:
Substance pH
Tomato Juice 4
Water 7
Baking Soda 9
a) Arrange them in order of their increasing Hydrogen ion concentration.
b) A few drops of Phenolphthalein are added to baking soda solution whose pH is 9. How will the colour of the indicator change?
c) Which of the above substances is best used for a person suffering from acidity?
d) How will the pH of tomato juice change if it is diluted by adding some water?
e) Name one synthetic indicator besides phenolphthalein.
35. Mirror formula is a relation between object distance (u), image distance (v) and focal length (f) of a spherical mirror.
It can be written as 1/u + 1/v = 1/f = 1/R
Where, R is the radius of curvature of the mirror.
This formula is valid in all situations for all spherical mirrors for all positions of the object. One case of image formation by concave mirror is shown below
Consider the case, in which a mirror forms a real image of height 4 cm of an object of height 1 cm placed 20 cm away from mirror.
Read the above passage carefully and give the answer of the following questions:
i) The distance from the object to its image is:
a) 20 cm b) 80 cm c) 60 cm d) 70 cm
ii) The focal length of the mirror is:
a) -16 cm b) 12 cm c) -15 cm d) 10 cm
iii) The radius of curvature of the mirror is:
a) -16 cm b) -14 cm c) -30 cm d) -32 cm
iv) The magnification of the image is:
a) 3 b) -6 c) -4 d) 8
36. Smita was unable to see distinctly words written on the blackboard of her classroom from her seat and had to come closer to the blackboard to read the words clearly. So she got her eyes tested in an eye clinic. The doctor suggested her to use spectacles with lens of power -1.5D continuously. Smita also observed that her grandmother always uses spectacles whether reading a newspaper or watching a television.
i) Name the type of defect Smita is suffering from and the lens used for correcting the defect?
ii) What is the value of near point and far point for Smita’s eye?
iii) Name the eye defect Smita’s grandmother is suffering from?
iv) What type of lens is being used by Smita’s grandmother for correcting the defect.
Section – C
37. How is oxygen and carbon dioxide transported in human beings?
38. What are the two main functions of lymph?
39. Comment on the statement that for viewing of nearby objects ciliary muscles contract and for viewing far off objects ciliary muscles are relaxed.
40. Give reasons for the following:
i) Plaster of Paris is stored in moisture proof container
ii) Baking powder makes the cake fluffy and spongy.
Section – D
41. a) What is meant by power of lens?
b) State and define the SI unit of power of lens.
c) A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with each other. Calculate the lens power of this combination.
42. A compound A is used in the manufacture of cement. When dissolved in water it evolves a large amount of heat and forms compound B.
i) Identify A and B
ii) Write chemical equation for the reaction of A with water
iii) List two types of reaction in which this reaction may be classified.
43. During respiration pyruvic acid is produced as end product of glycolysis. State the end products formed from iron further breakdown in each of the following cases.
a) In absence of oxygen in yeast
b) Lack of oxygen in muscles
c) Presence of oxygen in mitochondria
Section – E
44. i) What is meant by least distance of distinct vision? How does this vary between the very young and old people?
ii) What happens to the image distance in the normal human eye when we decrease the distance of an object, say 10 m to 1 m? Justify your answer.
iii) What is the name of screen of eye where image of object is formed? What is the nature of image formed on the screen?
45. i) Dry HCl gas does not change the colour of dry litmus blue. Give reason.
ii) What is milk of magnesia? Where is it used?
iii) A student dropped a few pieces of marble in dilute HCl in a test tube. A brisk effervescence of a gas was evolved which was then passed through lime water
a) Identify the gas
b) What change would you observe in lime water.
c) Write balanced equations for both the changes observed.
46. a) Define excretion.
b) Name the basic filtration unit present in the kidney.
c) Draw excretory system in human beings and label the following organs of excretory system which perform following function:
i) form urine
ii) is a long tube which collects urine from kidney
iii) store urine until it is passed out.