Please refer to Class 10 Science Sample Paper Set A below provided with solutions. All Class 10 Science Sample Paper have been prepared based on the latest syllabus and examination guidelines issued by CBSE, NCERT and KVS. All questions have been provided with solutions.
Class 10 Science Sample Paper Set A
Time: 3 Hours Maximum Marks: 80
(i) The question paper comprises four sections A, B, C and D. There are 36 questions in the question papers. All questions are compulsory.
(ii) Section–A – question no. 1 to 20 – all questions and parts thereof are of one mark each. These questions contain multiple choice questions (MCQs), very short answer questions and assertion – reason type questions. Answers to these should be given in one word or one sentence.
(iii) Section–B – question no. 21 to 26 are short answer type questions, carrying 2 marks each. Answers to these questions should in the range of 30 to 50 words.
(iv) Section–C – question no. 27 to 33 are short answer type questions, carrying 3 marks each. Answers to these questions should in the range of 50 to 80 words.
(v) Section–D – question no. – 34 to 36 are long answer type questions carrying 5 marks each. Answer to these questions should be in the range of 80 to 120 words.
(vi) There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
(vii) Wherever necessary, neat and properly labeled diagrams should be drawn.
Question 1. List two observations when iron nails are immersed in copper sulphate solution for about 20 minutes. (1 Marks)
Why should a magnesium ribbon be cleaned before burning in air?
Answer. Iron nail become brownish in colour and the blue colour of copper sulphate solution fade
To remove the oxide layer (which is formed due to the reaction of magnesium with air), the presence of which slows down the oxidation process.
Question 2. Write chemical name and formula of a salt used to set fractured bones in hospitals. (1 Marks)
Answer. Calcium sulphate hemihydrate CaSO4. ½ H2O
Question 3. Which of the following compounds can have a triple bond? (1 Marks)
Answer. b) C3H4
Question 4. Why does the Sun appear white at noon? (1 Marks)
Answer. The light is least scattered at noon.
Question 5. Both a spherical mirror and a spherical lens have a focal length of + 10 cm.What type of mirror and lens are these?
Name the part of a lens through which a ray of light passes without suffering any deviation (1 Marks)
Answer. Both are convex
Question 6. A pencil when dipped in water in a glass tumbler appears to be bent at the interface of air and water. Will the pencil appear to be bent to the same extent, if instead of water we use liquids like, kerosene or turpentine? Support your answer with reason. (1 Marks)
Answer. No. Bending will be different in different liquids since velocity of light at the interface separating two media depends on the relative refractive index of the medium.
Question 7. Which diagram shows the magnetic field lines around a current carrying circular loop ? (1 Marks)
Answer. Option b)
Question 8. The phenomenon of electromagnetic induction is: (1 Marks)
a) the process of charging a body.
b) the process of generating magnetic field due to a current passing through a coil.
c) producing induced current in a coil due to relative motion between a magnet and the coil.
d) the process of rotating a coil of an electric motor.
Answer. Option c) producing induced current in a coil due to relative motion between a magnet and the coil
Question 9. Which will have more electrical resistivity a piece of paper or a metal? (1 Marks)
Answer. A piece of paper
Question 10. Veins are thin walled and have valves. Justify. (1 Marks)
Answer. Veins have thin walls because the blood there is no longer under pressure and they have valves to ensure blood flow in one direction.
Question 11. Why the rate of breathing in aquatic organisms is much faster than that seen in terrestrial organisms? (1 Marks)
Trachea in Human beings does not collapse. Why? (1 Marks)
Answer. The amount of dissolved oxygen in water is low compared to the amount of oxygen in the air.
Because of presence of cartilaginous rings in trachea.
Question 12. We often use the word environment. What does it mean? (1 Marks)
Name any two man-made ecosystems.
Answer. A unit of biosphere in which biotic and abiotic components interact with each other.
Crop fields/ Gardens/ Aquarium/ Parks/ (any other two)
Question 13. Define excretion. (1 Marks)
For question numbers 14, 15 and 16, two statements are given- one labeled Assertion (A) and the other labeled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below:
a) Both A and R are true, and R is correct explanation of the assertion.
b) Both A and R are true, but R is not the correct explanation of the assertion.
c) A is true, but R is false.
d) A is false, but R is true.
Answer. Process involved in removal of nitrogenous / harmful metabolic waste from the body.
Question 14. Assertion: Copper is kept open in air, it slowly loses its shining brown surface and gains a green coating (1 Marks)
Reason: Copper is highly reactive metal.
Answer. c) A is true, but R is false.
Question 15. Assertion: Energy flow in food chains is always unidirectional. (1 Marks)
Reason: Only 10% energy is transferred to the next trophic level.
Assertion: Use of kulhads is environmental friendly.
Reason: Kulhads are non-biodegradable.
Answer. b) Both A and R are true, but R is not the correct explanation of the assertion.
c) A is true, but R is false.
Question 16. Assertion: When pure breed tall plants are crossed with pure breed short plants, all the plants in F1 progeny are tall. When the tall plants of F1 progeny are crossed, short plants re-appear in F2 progeny. (1 Marks)
Reason: Traits are independently inherited.
Answer. a) Both A and R are true, and R is correct explanation of the assertion.
|Answer Q. No 17 – 20 contain five sub-parts each. You are expected to answer any four sub-parts in these questions.|
Question 17. Read the following and answer any four questions from 17 (i) to 17 (v). (1× 4 marks)
In human beings, the alimentary canal is a long tube with muscular walls, glandular epithelial lining and varying diameter. It extends from mouth to the anal opening (anus). When uncoiled the elementary canal, measures nearly 9 metre long tube in which the ducts of several digestive glands open to secrete their respective digestive secretions. The elementary canal consists of several organs. These organs are given below in order in which they are involved in digesting food: mouth, buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine.
(i) Salivary glands are present in which region of alimentary canal?
(b) Small intestine
(c) Buccal cavity
Answer. (c) Buccal cavity
(ii) Pancreas secretes
(a) Bile salts
(b) Insulin and glucagon
(c) Pepsin and lipase
(d) Amylase and pepsin
Answer. (b) Insulin and glucagon
(iii) Which gland secretes bile?
(c) Small Intestine
(d) None of these
Answer. (b) Liver
(iv) Protein is digested in which of the following organ?
(b) stomach and small intestine
(c) large intestine
(d) None of these
Answer. (b) stomach and small intestine
(v) Which of the following is the final product of the digestion of protein?
(a) Amino acids
(d) None of these
Answer. (a) Amino acids
Question 18. Read the following and answer any four questions from 18 (i) to 18 (v). (1× 4 marks)
The ability of an atom to donate electrons and form positive ion (cation) is known as electro positivity or metallic character. Down the group, metallic character increases due to increase in atomic size and across the period, from left to right electro positivity decreases due to decrease in atomic size.
The ability of an atom to accept electrons to form a negative ion (anion) is called non-metallic character or electronegativity. The elements having high electro-negativity have a higher tendency to gain electrons and form anion. Down the group, electronegativity decreases due to increase in atomic size and across the period, from left to right electronegativity increases due to decrease in atomic size.
(i) Which of the following correctly represents the decreasing order of metallic character of Alkali metals plotted in the graph?
Answer. (c) Cs>Rb>K>Na>Li
(ii) Hydrogen is placed along with Alkali metals in the modern periodic table though it shows non-metallic character
(a) as Hydrogen has one electron & readily loses electron to form negative ion
(b) as Hydrogen can easily lose one electron like alkali metals to form positive ion
(c) as Hydrogen can gain one electron easily like Halogens to form negative ion
(d) as Hydrogen shows the properties of non-metals
Answer. (b) as Hydrogen can easily lose one electron like alkali metals to form positive ion
(iii) Which of the following has highest electronegativity?
Answer. (a) F
(iv) Identify the reason for the gradual change in electronegativity in halogens down the group.
(a) Electronegativity increases down the group due to decrease in atomic size
(b) Electronegativity decreases down the group due to decrease in tendency to lose electrons
(c) Electronegativity decreases down the group due to increase in atomic radius/ tendency to gain electron decreases
(d) Electronegativity increases down the group due to increase in forces of attractions between nucleus & valence electrons
Answer. (c) Electronegativity decreases down the group due to increase in atomic radius/ tendency to gain electron decreases
(v)Which of the following reason correctly justifies that “Fluorine (72pm) has smaller atomic radius than Lithium (152pm)”?
(a) F and Li are in the same group. Atomic size increases down the group
(b) F and Li are in the same period. Atomic size increases across the period due to increase in number of shells
(c) F and Li are in the same group. Atomic size decreases down the group
(d) F and Li are in the same period and across the period atomic size/radius decreases from left to right.
Answer. (d) F and Li are in the same period and across the period atomic size/radius decreases from left to right.
Question 19. Read the following and answer any four questions from 19 (i) to 19 (v) (1× 4 marks)
In the concave mirror nature, position and size of the image formed by a concave mirror depends on the position of the object in relation to points P, F and C. The image formed is real for some positions of the object. It is found to be a virtual image for a certain other position. The image is either magnified, reduced or has the same size, depending on the position of the object
(i) What will be the position of the image if the object is placed at infinity?
(a) Beyond C
(b) Between F and C
(c) At infinity
(d) At the focus P
Answer. (d) At the focus P
(ii) For an image to be of same size as the object what will be the position of the object?
(a) At F
(b) At C
(c) Between C and F
(d) Beyond C
Answer. (b) At C
(iii) If the image formed behind a concave mirror what will be the nature of the image
(d) None of the above
Answer. (c) Both(a)&(b)
(iv)Highly diminished point-size image is formed
(a) At the focus F
(b) At infinity
(c) Behind the mirror
(d) At C
Answer. (a) At the focus F
(v) If the object is placed at F size of the image is…….
(a) Same size
(b) At infinity
(c) Behind the mirror
(d) At C
Answer. (b) At infinity
Question 20. Read the following and answer any four questions from 20 (i) to 20 (v) (1× 4 marks)
A student drew the following schematic of a device that could convert some electricity supplied to it into rotational motion. Then referring to the circuit diagram he assembled and connected the given circuit. To increase the effect he tries manipulating with current and the design of the coil.
(i) the above circuit is a schematic of
(a) A solenoid
(b) An electric generator
(c) A rectangular loop
(d) An electric motor
Answer. (d) An electric motor
(ii) what type of energy conversion is observed in the above device?
(a) Mechanical to Magnetic
(b) Electrical to Magnetic
(c) Electrical to Mechanical
(d) None of the above
Answer. (c) Electrical to Mechanical
(iii) Correct labeling for (i), (ii) and (iii) respectively is
(a) Carbon brush, split ring, soft iron core
(b) Soft iron core, carbon brush, split ring
(c) Soft iron core, split ring, carbon brush
(d) Carbon brush, soft iron core, split ring
Answer. (c) Soft iron core, split ring, carbon brush
(iv)The arm CD of the rectangular coil will experience a force initially in the direction
(c) Towards left
(d) Not well defined
Answer. (a) Upwards
(v) The device used to reverse the direction of current through a circuit is, called
(b) magnetic needle
(d) none of these
Answer. (a) commutator
Question 21. Blood circulation in human heart is called double circulation. Why? (2 marks)
Leaves of a healthy potted plant were coated with Vaseline. Will this plant remain healthy for long? Give reason to justify your answer.
Answer. The blood circulation in human heart is called double circulation because the blood passes through the heart twice in one complete cycle of the body – once through the right half in the form of deoxygenated blood and once through the left half in the form of oxygenated blood.
No, it will not remain healthy. It will soon die because Vaseline covers the stomata. Hence exchange of gases and transpiration stops.
Question 22. Draw labelled diagrams to show the various steps of obtaining nutrition in Amoeba. (2 marks)
Answer. Diagram Page no 98 Figure 6.5 – NCERT textbook
Question 23. Give reason why carbon neither form C4+ cations nor C 4- anions but form covalent compounds which are bad conductors of electricity. (2 marks)
Draw all possible isomers of butane.
Answer. Carbon has 4 valance electrons. It cannot lose 4 electrons because very high amount of energy is needed. It also cannot gain four electrons because 6 protons cannot hold 10 electrons. It can can share four electrons to form four covalent bonds. Covalent compounds do not conduct electricity because they do not form ions.
Question 24. Generally, when metals are treated with mineral acids, hydrogen gas is liberated but when metals (except Mn and Mg), are treated particularly with HNO3, hydrogen is not liberated, why ? (2 marks)
Answer. It is because HNO3 is a strong oxidizing agent. It oxidizes the H2 produced toH2O.
Question 25. In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen. (2 marks)
Name the phenomenon. State the colors seen at X and Y.
Answer. The phenomenon is called dispersion.
Question 26. (a)Name and define the SI unit of current. (2 marks)
(b) Write Joule’s law of heating.
Answer. (a) Ampere,
Flow of 1 coulomb of charge per second / 1 ampere =1 coulomb/1 second
(b) Joule’s law of heating – Heat produced in a resistor is
(i) directly proportional to the square of current for a given resistance,
(ii) directly proportional to the resistance for a given current and
(iii) directly proportional to the time for which the current flows through the resistor / H = I2Rt where, H = Heat produced, I = current, R = Resistance of the conductor and t = Time for which the current flows through the resistor
Note :If the candidate gives only the expression H = I2Rt award ½ mark only.
Question 27. Does genetic combination of mother play a significant role in determining the sex of a newborn? Justify. (3 marks)
A blue colour flower plant denoted by BB is cross bred with that of white colour flower plant denoted by bb.
a) State the colour of flower you would expect in their F1 generation plants.
b) What must be the percentage of white flower plants in F2 generation if flowers of F1 plants are self-pollinated?
c) State the expected ratio of the genotypes BB and Bb in the F2 progeny.
Answer. No, because mothers have a pair of X-chromosomes. All children will inherit an ‘X’ chromosome from their mother regardless of whether they are boys or girls.
a) Color of flower in F1 generation – Blue
b) Percent of white flowers in F2 generation- 25%
c) expected ratio of the genotypes BB and Bb in the F2 progeny- 1:2
Question 28. In the given food chain, suppose the amount of energy at fourth trophic level is 5 kJ, what will be the energy available at the producer level? (3 marks)
Grass → Grasshopper → Frog → Snake → Hawk
Give reason why food chains generally consist of only three or four steps.
Answer. 5000 k Joule,
Since so little energy is available for the next level of consumers, food chains generally consist of only three or four steps.
Question 29. Explain the processes of aerobic respiration in mitochondria of a cell and anaerobic respiration in yeast and muscle with the help of word equations. (3 marks)
Question 30. When potassium iodide solution is added to a solution of lead nitrate in a test tube a precipitate is formed. (3 marks)
i) What is the colour of this precipitate and name the compound precipitated.
ii) Write the balanced chemical equation for this reaction.
iii) List two types of reaction in which this reaction can be placed?
Answer. The colour of this precipitate formed is yellow. The compound precipitated is lead iodide
Types of reaction are:
1.Double displacement reaction
Question 31. An element X (atomic number 17) reacts with an element Y (atomic number 20) to form a divalent halide. (3 marks)
a) Where in the periodic table are elements X and Y placed?
b) Classify X and Y as metal (s), non-metal (s) or metalloid (s)
c) What will be the nature of oxide of element Y? Identify the nature of bonding in the compound formed.
Answer. (a) X belongs to Group 17 and 3rd period ,Y belongs to Group 2 and 4th period
(b) X — Non-metal and Y — Metal
(c) Basic oxide; Ionic bonding
Question 32. (i)Explain the formation of magnesium chloride with the help of electron dot structure. (At. Number Mg=12, Cl=17) (3 marks)
(ii)Why do ionic compounds have high melting and boiling points?
(b) Because a considerable amount of energy is required to break the strong inter-ionic attraction.
Question 33. We wish to obtain an equal sized inverted image of a candle flame on a screen kept at distance of 4 m from the candle flame. (3 marks)
(a) Name the type of lens that should be used.
(b) What should be the focal length of the lens and at what distance from the candle flame the lens be placed.
(c) Draw a labelled diagram to show the image formation in this case.
Answer. a) Convex lens
b) Focal length of the lens is 2 m. Distance of candle flame from the lens is 4 m
c) Ray Diagram
Question 34. A cloth strip dipped in onion juice is used for testing a liquid ‘X’. The liquid ‘X’ changes its odor. Which type of an indicator is onion juice? The liquid ‘X’ turns blue litmus red. List the observations the liquid ‘X’ will show on reacting with the following : (5 marks)
(a) Zinc granules
(b) Solid sodium carbonate
Write the chemical equations for the reactions involved.
Define water of crystallization. Give the chemical formula for two compounds as examples. How can it be proved that the water of crystallization makes a difference in the state and colour of the compounds?
Answer. Olfactory indicator
(a) Colourless and Odorless gas is evolved with bubbles.
Zinc + Acid → Zinc Salt + H2 ↑
( or by using any example of acid e.g. HCl/ H2SO4)
(b) Brisk effervescence/ colorless and odorless gas is evolved.
Sodium carbonate + Acid → Sodium salt of Acid + Water + Carbon dioxide↑
( or by using any example of acid like HCl/ H2SO4)
*Water of crystallization is the fixed number of water molecules present in one formula unit of a salt.
*Examples CuSO4 .5H2O
Na2CO3.10 H2O (or Any other)
* Heat a few crystals of hydrated copper sulphate (blue colour) in a dry boiling tube. Water droplets are seen in the boiling tube.
Colour: The colour of copper sulphate changes to white.
State: The blue crystal changes to white powder.
Question 35. Draw a neat diagram showing fertilization in a flower and label (a) Pollen tube, (b) Male germ cell and (c) Female germ cell, on it. (5 marks)
Explain the process of fertilization in a flower. What happens to the (i) ovary and (ii) ovule after fertilization?
Question 36. Draw a schematic diagram of a circuit consisting of a battery of 3 cells of 2 V each, a combination of three resistors of 10 Ω, 20 Ω and 30 Ω connected in parallel, a plug key and an ammeter, all connected in series. (5 marks)
Use this circuit to find the value of the following :
(a) Current through each resistor
(b) Total current in the circuit
(c) Total effective resistance of the circuit
Two identical resistors, each of resistance 15 Ω, are connected in
(i) series and (ii) parallel, in turn to a battery of 6 V. Calculate the ratio of the power consumed in the combination of resistors in each case.