CBSE Class X Science Sample Question Paper 2019-20 : cbseacademic.nic.in

Name of the Board : CBSE Academic
Class : X STD
Document Type : Sample Question Paper
Subject : Science
Year : 2019-20
Website : http://cbseacademic.nic.in/SQP_CLASSX_2019_20.html

CBSE X Science Question Paper

Download Question Paper of Class X Science Sample Question Paper 2019-20 is now available in the official website of CBSE Academic.

Related : CBSE Mathematics Sample Question Paper 2019-20 : www.pdfquestion.in/34417.html

Section A

1 Define catenation. 1
2 How does valency of an element vary across a period? 1

3 Answer question numbers 3(a) – 3(d) on the basis of your understanding of the following paragraph and the related studied concepts. Renewable energy sources such as wind energy are vital for the Indian economy, not only from the point of view of supply, but also from the perspective of environmental and social benefits.

India is the world’s fifth largest wind-power producer and the largest windmill facilities in India are installed in Tamil Nadu. Muppandal is a small village of Tamil Nadu and one of the most important sites of wind-farm in the state.

It uses wind from the Arabian Sea to produce renewable energy. The suitability of Muppandal as a site for wind farms stems from its geographical location as it has access to the seasonal monsoon winds.

3(a) State the principle behind electric generator. 1
3(b) The output frequency of wind turbine is 50 Hz. What is meant by this statement? 1
3(c) Why do you think Muppandal is at an advantageous position for this project? 1
3(d) Based on the data represented in the graph below, which of the two cities A or B would be an ideal location for establishing a wind-farm and why?

4 Question numbers 4(a) – 4(d) are based on the two tables given below. Study these tables related to blood sugar levels and answer the questions that follow.

4(a) Refer to Table B showing the blood report of the levels of glucose of patients X and Y. Infer the disease which can be diagnosed from the given data.

4(b) Identify the hormone whose level in the blood is responsible for the above disease. 1

4(c) Which one of the following diets would you recommended to the affected patient?
i) High sugar and low fat diet.
ii) Low sugar and high protein diet.
iii) High Fat and low fiber diet.
iv) Low sugar and high fiber diet.

4(d) Refer to the Table A and suggest the value of the mean blood glucose level beyond which doctor’s advice is necessary
i) 180 mg/dL
ii) 115 mg/dL
iii) 50 mg/dL
iv) 80 mg/dL

5 When we enter a dark room coming from outside, immediately the things inside the room do not appear clear to our eyes. This is because
i) pupils do not open at all in the dark.
ii) pupils take time to adjust.
iii) light travels slower in a dark room.
iv) pupils open very quickly in the dark.
OR
The phenomena of light responsible for the working of the human eye is
i) reflection
ii) refraction
iii) power of accommodation
iv) persistence of vision

6. When a 4V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resister is
i) 4 O
ii) 40 O
iii) 400 O
iv) 0.4 O

7 Unit of electric power may also be expressed as
i) volt-ampere
ii) kilowatt-hour
iii) watt-second
iv) joule-second

8 It was found that water from a river was contaminated with Coliform bacteria. Which one of the following pollutant might have got mixed with the water?
i) Fertilizer run off
ii) Industrial waste
iii) Pesticides
iv) Human faecal matter
OR
Which one of the following stakeholders of forests causes the maximum damage to forest?
i) People who live in or around the forest
ii) The forest department of the government
iii) The wildlife and native enthusiasts
iv) The industrialists

Section B

15 (i) Write two observations when lead nitrate is heated in a test tube.
(ii) Name the type of reaction.
(iii) Write a balanced chemical equation to represent the above reaction.

16 A compound ‘X’ of sodium is used as an antacid and it decomposes on strong heating.
(i) Name the compound ‘X’ and give its chemical formula.
(ii) Write a balanced chemical equation to represent the decomposition of ‘X’.
(iii) Give one use of compound ‘X’ besides an antacid.
OR
You are provided with 90 mL of distilled water and 10 mL of concentrated sulphuric acid to prepare dilute sulphuric acid.
(i) What is the correct way of preparing dilute sulphuric acid? Give reason.
(ii) How will the concentration of H3O + ions change on dilution?

17 Two elements X and Y have atomic numbers 12 and 16 respectively. To which period of the modern periodic table do these two elements belong? What type of bond will be formed between them and why? Also give the chemical formula of the compound formed.

18 (i) Create a terrestrial food chain depicting four trophic levels.
(ii) Why do we not find food chains of more than four trophic levels in nature?
OR
How will you create an artificial aquatic ecosystem, which is self-sustainable?

19 Explain the processes of aerobic respiration in mitochondria of a cell and anaerobic respiration in yeast and muscle with the help of word equations.

20 In a pea plant, the trait of flowers bearing purple colour (PP) is dominant over white colour (pp). Explain the inheritance pattern of F1 and F2 generations with the help of a cross following the rules of inheritance of traits. State the visible characters of F1and F2 progenies.

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Section C

25 Metal X is found in nature as its sulphide XS. It is used in the galvanisation of iron articles. Identify the metal X. How will you convert this sulphide ore into the metal? Explain with equations.

OR
State the reason for the following
(i) Aluminium oxide is called an amphoteric oxide.
(ii) An iron strip dipped in a blue copper sulphate solution turns the blue solution pale green.
(iii) Hydrogen gas is not evolved when most metals react with nitric acid.
(iv) Calcium does not occur in free state in nature.
(v) Sodium or potassium metals are kept immersed under kerosene.

26 The formulae of four organic compounds are given below
C2H4 CH3COOH C2H5OH C2H6
(i) Which one of these compounds A, B, C or D is a saturated hydrocarbon?
(ii) Identify the organic acid and give its structural formula.

(iii) Which of the above compounds when heated at 443K in the presence of concentrated H2SO4 forms ethene as the major product? What is the role played by concentrated H2SO4 in this reaction? Also write the chemical equation involved.

(iv) Give a chemical equation when B and C react with each other in presence of concentrated H2SO4. Name the major product formed and mention one of its important use.