CBSE 10th exams 2019: The Board exams for class 10 will be held in February 2019. Students all across India are preparing for their Central Board of Secondary Education (CBSE) class 10 board exam. Here is a chance to check your preparedness for the boards.
Check out this science sample paper for class 10 CBSE board exam. Time yourself to access yourself properly. This sample paper is prepared to be completed in three hours and is maximum marks for 80.
CBSE Class 10 2019: Check this sample paper of Science
(i) The question paper comprises of five sections – A, B, C, D and E. You are to attempt all the sections.
(ii) All questions are compulsory.
(iii) Question numbers 1 and 2 in Section-A are one mark questions. They are to be answered in one word or in one sentence.
(iv) Question numbers 3 to 5 in Section- B are two marks questions. These are to be answered in about 30 words each.
(v) Question numbers 6 to 15 in Section-C are three marks questions. These are to be answered in about 50 words each.
(vi) Question numbers 16 to 21 in Section-D are 5 marks questions. These are to be answered in about 70 words each.
(vii) Question numbers 22 to 27, in Section- E, are based on practical skills. Each question is a two marks question. These are to be answered in brief
Q.1 State the role of decomposers in the ecosystem. 
Q.2 Mention any two ancient water harvesting techniques practised in Rajasthan. 
Q.3 List two distinguishing feature between acquired and inherited traits. 
Q.4 A substance Z, which is an oxide of a group 2 element, is used intensively in the cement industry. This element is present in bones also. On treatment with water, it forms a solution which turns red litmus blue. Identify Z and also write the chemical reactions involved. 
Q.5 Draw diagrams showing defects for eye using (i) -1.5D lens and (ii) +2.5 D lens. 
Q.6 a. Name the organ which is the site of complete digestion. [1+2]
b. Write the names and function of enzymes present in pancreatic juice.
Q.7 Compound X is available in the form of pellets or flakes in the lab. On the basis of the reactions given below. [1+1+1]
Write the name and chemical formulae of A, B and C.
Q.8 Mention three advantages of a solar cell?
Q.9 Suggest different chemical processes used for obtaining a metal from its oxides for metals in the middle of the reactivity series, bottom of the reactivity series and metals towards the top of the reactivity series. Support your answer with one example each. 
Q.10 a. Name the reproductive parts of a flower. [1+2]
b. Testes are located outside the abdominal cavity in scrotum. Why?
Q.11 In the electrolysis of water : 
a) Name the gas collected at anode and cathode
b) Why is the volume of gas collected at one electrode double than the other?
c) What would happen if dil H 2 SO 4 is not added to water?
Q.12 Rahul and Shashi are driving through Connaught Place in New Delhi. Their care was moving at a very slow speed. There was such a heavy traffic in the lane that their car was hardly moving. Rahul said to Shashi, “If the manufacturing of vehicles keep on increasing, it would become difficult to live in cities. We must take some measures to address the problem”. 
a. How can we address to this kind of problem of heavy traffic?
b. What are fossil fuels?
c. What values are shown by Rahul?
Q.13 Differentiate between the arrangement of elements in Mendeleev’s periodic table and Modern periodic table. 
Q.14 ‘pH has a great importance in our daily life’. Explain by giving three examples. 
A compound which is prepared from gypsum has the property of hardening when mixed with a proper quantity of water. Identify the compound and write its chemical formula. Write the chemical equation for its preparation. Mention any one use of the compound.
Q.15 A current of 1 ampere flows in a series circuit containing an electric lamp and a conductor of 5 ohm when connected to a 10 V battery. Calculate the resistance of the electric lamp. Now if a resistance of 10 ohm is connected in parallel with this series combination, what change (if any) in current flowing through 5 ohm conductor and potential difference across the lamp will take place? [1+1+1]
Q.16. a. i. Draw a neat diagram of human brain. [2+2+1]
ii. Label medulla and cerebellum. Write their functions.
b. ‘Both overproduction and underproduction of growth hormones lead to disorders in body’. Explain.
Q.17 You are given balls and stick model of six carbon atoms and fourteen hydrogen atoms and sufficient number of sticks. In how many ways one can join the models of six carbon atoms and fourteen hydrogen atoms to form different molecules of C6H14. 
Q.18 i. 10 mm long pin is placed vertically in front of a concave mirror. A 5 mm long image of the awl pin is formed at 30 cm in front of the mirror. Find the focal length of this mirror. [1+1+1+1+1]
ii. Figure below shows a ray of light as it travels from medium A to medium B. Find the refractive index of the medium B relative to medium A is
iii. Rays from Sun converge at a point 15 cm in front of a concave mirror. Where an object should be placed so that the size of its image is equal to the size of the object? 30cm
iv. The refractive index of diamond with respect to glass is 1.6 and an absolute refractive index of glass is 1.5. Find out the absolute refractive index of diamond.
v. Size of image of an object by a mirror having a focal length of 20 cm is observed to be reduced to 1/3rd of its size. At what distance the object has been placed from the mirror?
Q.19 i. Find out the following in the electric circuit given in figure below: [3+1+1]
a. potential difference across 4 ohm resistance
b. power dissipated in 4 ohm resistor
c. the difference in ammeter readings.
ii. What will be the energy used by the battery if the battery has to drive 6.28 X 10 18 electrons with potential difference of 20 V across the terminal?
iii. What is the minimum resistance which can be made using five resistors each of 1/5 ohm?
Q.20 a. Observe the given diagram and answer the questions. [1+2+2]
i. Identify the given labels.
ii. Give the functions of C and D
b. With the help of ray diagram name all the parts in sequence, through which atmospheric air
reaches the last part of our lungs.
Q.21 i. How to convert AC generator into DC generator? [1+3+1]
ii. A magnetic compass needle is placed in the plane of paper near point A as shown in the figure
below. In which plane should a straight current-carrying conductor be placed so that it passes
through A and there is no change in the deflection of the compass? Under what condition is the
deflection maximum and why?
iii. AB is a current carrying conductor in the plane of the paper as shown in the figure below. What are the directions of magnetic fields produced by it at points P and Q? Given r1> r2, where will the strength of the magnetic field be larger?
Q.22 Jiya was observing the temporary mount of leaf peel. She observed the opened stomata.
Draw a neat labelled diagram of the same. 
Q.23 What do you observe when you drop a few drops of acetic acid to a test tube containing:
a) Phenolphthalein c) distilled water 
b) Universal indicator d) sodium hydrogen carbonate
Q.24 Observe the diagram and identify X and Y. Give the function of X. 
Q.25 Riya performs two set of experiments to study the length of the foam formed which are as
Set I: she takes 10 ml of distilled water in test tube “A” and adds 5-6 drops of liquid soap in it and shakes the test tube vigorously.
Set II: she takes 10 ml of distilled water in a test tube “A” and adds 5-6 drops of liquid soap with half spoonful of CaSO4 in it and shakes the test tube.
Write your observation and reason.
Q .26 A student carries out an experiment and plots the V-I graph of three samples of nichrome
wire with resistances R1, R2 and R3 respectively.[Refer the figure below] Which of the
following is true and why?
(a) R1 = R2 = R3 b) R1> R2 > R3 c) R3 > R2 > R1 (d) R2 > R3 >R1 
Q.27 Under which of the following conditions a concave mirror can form an image larger than
the actual object? With the help of a diagram support your answer.
a. When the object is kept at a distance equal to its radius of curvature
b. When an object is kept at a distance less than its focal length
c. When an object is placed between the focus and centre of curvature
d. When an object is kept at a distance greater than its radius of curvature
— The paper is authored by TGT Science, VidyaGyan School, Bulandshahr