CBSE · Science
CBSE GRADE 10 SCIENCE 2023 SET 1
2023
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41 questions
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Q1
mcq
1 mark
The emission of brown fumes in the given experimental set-up is due to (setup: Lead nitrate heated over a Burner, producing Brown fumes)
a.
thermal decomposition of lead nitrate which produces brown fumes of nitrogen dioxide.
Correct Answer
b.
thermal decomposition of lead nitrate which produces brown fumes of lead oxide.
c.
oxidation of lead nitrate forming lead oxide and nitrogen dioxide.
d.
oxidation of lead nitrate forming lead oxide and oxygen.
Step-by-Step AI Explanation
Verified Method
Thermal decomposition of lead nitrate (2Pb(NO3)2 → 2PbO + 4NO2 + O2) releases nitrogen dioxide gas, which is brown in color. B is wrong because lead oxide is a yellow solid. C and D are wrong because this is a decomposition reaction, not oxidation.
Q2
mcq
1 mark
In the experimental setup given below, it is observed that on passing gas produced in the reaction in the solution 'X' the solution 'X' first turns milky and then colourless. (Setup: Dilute Hydrochloric Acid reacting with Sodium carbonate, gas passed into solution X.) The option that justifies the above stated observation is that 'X' is aqueous calcium hydroxide and
a.
it turns milky due to carbon dioxide gas liberated in the reaction and after sometime it becomes colourless due to formation of calcium carbonate.
b.
it turns milky due to formation of calcium carbonate and on passing excess of carbon dioxide it becomes colourless due to formation of calcium hydrogen carbonate which is soluble in water.
Correct Answer
c.
it turns milky due to passing of carbon dioxide through it. It turns colourless as on further passing carbon dioxide, sodium hydrogen carbonate is formed which is soluble in water.
d.
the carbon dioxide liberated during the reaction turns lime water milky due to formation of calcium hydrogen carbonate and after some time it turns colourless due to formation of calcium carbonate which is soluble in water.
Step-by-Step AI Explanation
Verified Method
Carbon dioxide reacts with calcium hydroxide (lime water) to form insoluble calcium carbonate, causing milkiness. Excess CO2 reacts further to form soluble calcium hydrogen carbonate, making the solution colorless. A, C, and D are incorrect due to misidentification of products or chemical properties.
Q3
mcq
1 mark
The table below has information regarding pH and the nature (acidic/basic) of four different solutions. Which one of the options in the table is correct?
a.
Lemon juice | Orange colour of pH paper | Approximate pH value 3 | Basic
b.
Milk of magnesia | Blue colour of pH paper | Approximate pH value 10 | Basic
Correct Answer
c.
Gastric juice | Red colour of pH paper | Approximate pH value 6 | Acidic
d.
Pure water | Yellow colour of pH paper | Approximate pH value 7 | Neutral
Step-by-Step AI Explanation
Verified Method
Milk of magnesia is a mild base (pH ~10) and turns pH paper blue. A is wrong because lemon juice is acidic. C is wrong because gastric juice has a pH closer to 1-2. D is wrong because pure water turns green (pH 7), not yellow.
Q4
mcq
1 mark
MnO₂ + x HCl → MnCl₂ + y H₂O + z Cl₂. In order to balance the above chemical equation, the values of x, y and z respectively are:
a.
6, 2, 2
b.
4, 1, 2
c.
4, 2, 1
Correct Answer
d.
2, 2, 1
Step-by-Step AI Explanation
Verified Method
The balanced equation is MnO2 + 4HCl → MnCl2 + 2H2O + Cl2. Balancing the atoms: Mn (1), O (2), H (4), Cl (4) on both sides. Thus x=4, y=2, z=1.
Q5
mcq
1 mark
Select washing soda from the following:
a.
NaHCO₃
b.
Na₂CO₃.5H₂O
c.
Na₂CO₃.10H₂O
Correct Answer
d.
NaOH
Step-by-Step AI Explanation
Verified Method
Washing soda is sodium carbonate decahydrate, with the formula Na2CO3.10H2O. A is baking soda, B is incorrect hydration, and D is caustic soda.
Q6
mcq
1 mark
Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from the following:
a.
A and C are isomers of hexane and B is benzene.
b.
A is an isomer of hexane, B is benzene and C is an isomer of hexene.
c.
A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.
Correct Answer
d.
A is cyclohexane and B and C are the isomers of benzene.
Step-by-Step AI Explanation
Verified Method
Cyclohexane (A) is a saturated cyclic hydrocarbon, while benzene (B) and other unsaturated cycles (C) contain double bonds. A is not an isomer of hexane (which is non-cyclic), and B/C are not isomers of each other.
Q7
mcq
1 mark
The following diagram shows the electrolytic refining of copper. Which of the following statements is incorrect description of the process?
a.
The impure metal from the anode dissolves into the electrolyte.
b.
The pure metal from the electrolyte is deposited on the cathode.
c.
Insoluble impurities settle down at the bottom of the anode.
d.
On passing the current through the electrolyte, the pure metal from the anode dissolves into the electrolyte.
Correct Answer
Step-by-Step AI Explanation
Verified Method
In electrolytic refining, impure metal (anode) dissolves into the electrolyte, but the process is not 'pure metal' dissolving; it is the metal atoms losing electrons to become ions, leaving impurities behind. Thus, calling it 'pure metal' is conceptually incorrect.
Q8
mcq
1 mark
Consider the following statements about small intestine and select the one which is NOT correct:
a.
The length of the small intestine in animals differs as it depends on the type of food they eat.
b.
The small intestine is the site of complete digestion of food.
c.
The small intestine receives secretions from liver and pancreas.
d.
The villi of the small intestine absorb water from the unabsorbed food before it gets removed from the body via the anus.
Correct Answer
Step-by-Step AI Explanation
Verified Method
The absorption of water from unabsorbed food occurs in the large intestine, not the small intestine. Statements A, B, and C are correct biological facts regarding the small intestine.
Q9
mcq
1 mark
An organism which breaks down the food material outside the body and then absorbs it is
a.
a plant parasite, Cuscuta
b.
an animal parasite, Tapeworm
c.
a bacteria, Rhizobium
d.
a fungi, Rhizopus
Correct Answer
Step-by-Step AI Explanation
Verified Method
Fungi like Rhizopus are saprotrophs; they secrete digestive enzymes outside their body to break down organic matter and then absorb the nutrients. Cuscuta and Tapeworms are parasites (ingest nutrients from a living host), and Rhizobium is a nitrogen-fixing bacteria living in root nodules.
Q10
mcq
1 mark
Which of the following metals do not corrode in moist air?
a.
Copper
b.
Iron
c.
Gold
Correct Answer
d.
Silver
Step-by-Step AI Explanation
Verified Method
Gold is a noble metal located at the bottom of the reactivity series, making it highly resistant to corrosion in moist air. Copper, iron, and silver react with gases in the air to form surface compounds (oxides, sulfides, or carbonates) and thus undergo corrosion.
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Q11
mcq
1 mark
Select from the following the correct statement about tropic movement in plants:
a.
It is due to stimulus of touch and temperature.
b.
It does not depend upon the direction of stimulus received.
c.
It is observed only in roots and not in stems.
d.
It is a growth related movement.
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Q12
mcq
1 mark
The statement that correctly describes the characteristic(s) of a gene is:
a.
In individuals of a given species, a specific gene is located on particular chromosome.
b.
A gene is not the information source for making proteins in the cell.
c.
Each chromosome has only one gene located all along its length.
d.
All the inherited traits in human beings are not controlled by genes.
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Q13
mcq
1 mark
In domestic electric circuits the wiring with 15 A current rating is for the electric devices which have
a.
higher power ratings such as geyser.
b.
lower power ratings such as fan.
c.
metallic bodies and low power ratings.
d.
non-metallic bodies and low power ratings.
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Q14
mcq
1 mark
If four identical resistors, of resistance 8 ohm, are first connected in series so as to give an effective resistance Rs, and then connected in parallel so as to give an effective resistance Rp, then the Rs/Rp is
a.
32
b.
2
c.
0.5
d.
16
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Q15
mcq
1 mark
The resultant magnetic field at point 'P' situated midway between two parallel wires (placed horizontally) each carrying a steady current I is
a.
in the same direction as the current in the wires.
b.
in the vertically upward direction.
c.
zero
d.
in the vertically downward direction.
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Q16
mcq
1 mark
If the current I through a resistor is increased by 100% (at constant temperature), the increase in power dissipated will be
a.
100%
b.
200%
c.
300%
d.
400%
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Q17
mcq
1 mark
Assertion (A): Genes inherited from the parents decide the sex of a child.
Reason (R): X chromosome in a male child is inherited from his father.
a.
Both (A) and (R) are true and (R) is the correct explanation of (A).
b.
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
c.
(A) is true, but (R) is false.
d.
(A) is false, but (R) is true.
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Q18
mcq
1 mark
Assertion (A): The colour of aqueous solution of copper sulphate turns colourless when a piece of lead is added to it.
Reason (R): Lead is more reactive than copper, and hence displaces copper from its salt solution.
a.
Both (A) and (R) are true and (R) is the correct explanation of (A).
b.
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
c.
(A) is true, but (R) is false.
d.
(A) is false, but (R) is true.
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Q19
mcq
1 mark
Assertion (A): The strength of the magnetic field produced at the centre of a current carrying circular coil increases on increasing the number of turns in it.
Reason (R): The current in each circular turn has the same direction and the magnetic field due to each turn then just adds up.
a.
Both (A) and (R) are true and (R) is the correct explanation of (A).
b.
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
c.
(A) is true, but (R) is false.
d.
(A) is false, but (R) is true.
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Q20
mcq
1 mark
Assertion (A): Left atrium receives oxygenated blood from pulmonary vein.
Reason (R): Right atrium transfers deoxygenated blood to the right ventricle, which pumps it to the lungs for oxygenation.
a.
Both (A) and (R) are true and (R) is the correct explanation of (A).
b.
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
c.
(A) is true, but (R) is false.
d.
(A) is false, but (R) is true.
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Q21
short answer
2 marks
A plant hormone helps in bending of stem towards light. Name the hormone and explain how is the movement achieved.
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Q22
short answer
2 marks
(a) (i) A compound 'X' which is prepared from gypsum has the property of hardening when mixed with proper quantity of water. Identify 'X' and write its chemical formula.
(ii) State the difference in chemical composition between baking soda and baking powder.
OR
(b) Write balanced chemical equation for the reaction that occurs when:
(i) blue coloured copper sulphate crystals are heated and
(ii) Sodium hydrogen carbonate is heated during cooking.
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Q23
short answer
2 marks
Name the part of the human excretory system where nephrons are found. Write the structure and function of nephrons.
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Q24
short answer
2 marks
Write the constituents of solder alloy. Which property of solder makes it suitable for welding electrical wires?
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Q25
short answer
2 marks
Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
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Q26
short answer
2 marks
(a) A narrow beam XY of white light is passing through a glass prism ABC as shown in the diagram. Trace it on your answer sheet and show the path of the emergent beam as observed on the screen PQ. Name the phenomenon observed and state its cause.
OR
(b) It is observed that the power of an eye to see nearby objects as well as far off objects diminishes with age.
(i) Give reason for the above statement.
(ii) Name the defect that is likely to arise in the eyes in such a condition.
(iii) Draw a labelled ray diagram to show the type of corrective lens used for restoring the vision of such an eye.
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Q27
long answer
3 marks
A chemical compound X is used in glass, soap and paper industries. On treatment with ethanoic acid, it forms salt, water and carbon dioxide.
(a) Identify X.
(b) How is this compound obtained from brine? Write the equations involved.
(c) State the number of molecules of water of crystallization present in compound X.
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Q28
long answer
3 marks
(a) Identify the reducing agent in the following reactions:
(i) 4NH3 + 5O2 → 4NO + 6H2O
(ii) H2O + F2 → HF + HOF
(iii) Fe2O3 + 3CO → 2Fe + 3CO2
(iv) 2H2 + O2 → 2H2O
(b) Define a redox reaction in terms of gain or loss of oxygen.
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Q29
long answer
3 marks
A student wants to project the image of a candle flame on a screen 60 cm in front of a mirror by keeping the candle at a distance of 15 cm from its pole.
(a) Name the type of mirror used.
(b) Also calculate:
(i) Magnification of the image produced
(ii) Distance between object and its image
(c) Draw a ray diagram to show the image formation.
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Q30
short answer
3 marks
(a)
(i) State the role of ATP in cellular respiration.
(ii) What ensures sufficient exchange of gases in plants?
(iii) State the conditions on which the direction of diffusion of gases in plant depend upon.
OR
(b)
(i) What is the internal energy reserve in plants and animals?
(ii) How desert plants perform photosynthesis if their stomata remain closed during the day?
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Q31
short answer
3 marks
(a)
(i) State the rule used to find the force acting on a current carrying conductor placed in a magnetic field.
(ii) Given below are three diagrams showing entry of an electron in a magnetic field. Identify the case in which the force will be (1) maximum and (2) minimum respectively. Give reason for your answer.
OR
(b)
(i) Draw the pattern of magnetic field lines of:
(1) a current carrying solenoid
(2) a bar magnet
(ii) List two distinguishing features between the two fields.
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Q32
short answer
3 marks
(a)
(i) Why does a kitchen garden called an artificial ecosystem while a forest is considered to be a natural ecosystem?
(ii) While designing an artificial ecosystem at home, write any two things to be kept in mind to convert it into a self-sustaining system. Give reason to justify your answer.
OR
(b)
(i) Construct a food chain of four trophic levels comprising the following: Hawk, snake, plants, rat.
(ii) 20,000 J of energy was transferred by the producers to the organism of second trophic level. Calculate the amount of energy that will be transferred by organisms of the third trophic level to the organisms of the fourth trophic level.
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Q33
short answer
A person cannot see distinctly the object placed beyond 5 m from his eyes. Name the defect of vision the person is suffering from. Draw a ray diagram to illustrate this defect. List its two possible causes. Name the lens used for the correction of this defect.
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Q34
long answer
5 marks
(a) Mention the role of the following organs of human male reproductive system:
(i) Testis
(ii) Scrotum
(iii) Vas-deferens
(iv) Seminal vesicle
(b) What is Placenta? State its function in a human female.
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Q35
long answer
5 marks
(a) An electric iron consumes energy at a rate of 880 W when heating is at the maximum rate and 330 W when the heating is at the minimum. If the source voltage is 220 V, calculate the current and resistance in each case.
(b) What is heating effect of electric current?
(c) Find an expression for the amount of heat produced when a current passes through a resistor for some time.
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Q36
long answer
5 marks
(a) A saturated organic compound 'A' belongs to the homologous series of alcohols. On heating 'A' with concentrated sulphuric acid at 443 K, it forms an unsaturated compound 'B' with molecular mass 28 u. The compound 'B' on addition of one mole of hydrogen in the presence of Nickel, changes to a saturated hydrocarbon 'C'.
(i) Identify A, B and C.
(ii) Write the chemical equations showing the conversion of A into B.
(iii) What happens when compound C undergoes combustion?
(iv) State one industrial application of hydrogenation reaction.
(v) Name the products formed when compound A reacts with sodium.
OR
(b)
(i) With the help of diagram, show the formation of micelles, when soap is applied on oily dirt.
(ii) Take two test tubes X and Y with 10 mL of hard water in each. In test tube 'X', add few drops of soap solution and in test tube Y add a few drops of detergent solution. Shake both the test tubes for the same period.
(1) In which test tube the formation of foam will be more? Why?
(2) In which test tube is a curdy solid formed? Why?
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Q37
long answer
5 marks
(i) Identify A, B and C.
(ii) Write the chemical equations showing the conversion of A into B.
(iii) What happens when compound C undergoes combustion?
(iv) State one industrial application of hydrogenation reaction.
(v) Name the products formed when compound A reacts with sodium.
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Q37
long answer
In order to trace the inheritance of traits Mendel crossed pea plants having one contrasting character or a pair of contrasting characters. When he crossed pea plants having round and yellow seeds with pea plants having wrinkled and green seeds, he observed that no plants with wrinkled and green seeds were obtained in the F1 generation. When the F1 generation pea plants were cross-bred by self-pollination, the F2 generation had seeds with different combinations of shape and colour also.
(a) Write any two pairs of contrasting characteristics of pea plant used by Mendel other than those mentioned above.
(b) Differentiate between dominant and recessive traits.
(c) State the ratio of the combinations observed in the seeds of F2 generation (in the above case). What do you interpret from this result?
OR
(c) Given below is a cross between a pure violet flowered pea plant (V) and a pure white flowered pea plant (v). Diagrammatically explain what type of progeny is obtained in F1 generation and F2 generation. Pure violet flowered plant × Pure white flowered plant. (VV) (vv)
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Q38
long answer
5 marks
(i) With the help of diagram, show the formation of micelles, when soap is applied on oily dirt.
(ii) Take two test tubes X and Y with 10 mL of hard water in each. In test tube 'X', add few drops of soap solution and in test tube Y add a few drops of detergent solution. Shake both the test tubes for the same period.
(1) In which test tube the formation of foam will be more? Why?
(2) In which test tube is a curdy solid formed? Why?
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Q38
long answer
Hold a concave mirror in your hand and direct its reflecting surface towards the sun. Direct the light reflected by the mirror on to a white card-board held close to the mirror. Move the card-board back and forth gradually until you find a bright, sharp spot of light on the board. This spot of light is the image of the sun on the sheet of paper; which is also termed as 'Principal Focus' of the concave mirror.
(a) List two applications of concave mirror.
(b) If the distance between the mirror and the principal focus is 15 cm, find the radius of curvature of the mirror.
(c) Draw a ray diagram to show the type of image formed when an object is placed between pole and focus of a concave mirror.
OR
(c) An object 10 cm in size is placed at 100 cm in front of a concave mirror. If its image is formed at the same point where the object is located, find:
(i) focal length of the mirror, and
(ii) magnification of the image formed with sign as per Cartesian sign convention.
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Q39
long answer
Almost all metals combine with oxygen to form metal oxides. Metal oxides are generally basic in nature. But some metal oxides show both basic as well as acidic behaviour. Different metals show different reactivities towards oxygen. Some react vigorously while some do not react at all.
(a) What happens when copper is heated in air? (Give the equation of the reaction involved).
(b) Why are some metal oxides categorized as amphoteric? Give example.
(c) Complete the following equations:
(i) Na2O + H2O →
(ii) Al2O3 + 2NaOH →
OR
(c) On burning Sulphur in oxygen a colourless gas is produced.
(i) Write chemical equation for the reaction.
(ii) Name the gas formed.
(iii) State the nature of the gas.
(iv) What will be the action of this on a dry litmus paper?
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