CBSE Class 10 Science Sample Paper 2023-24: Prepare Like a Pro with Solutions

The CBSE Class 10 Science Sample Paper 2023-24 is an official document released by the Central Board of Secondary Education (CBSE) to help students prepare for the board exams. The sample paper contains questions from all the chapters in the CBSE Class 10 Science syllabus, along with solutions.

Solving the sample paper is a great way to get a feel for the exam pattern and to identify the important topics that you need to focus on. The solutions will help you to understand the correct way to answer the questions and to avoid common mistakes.

Here are some tips on how to use the CBSE Class 10 Science Sample Paper 2023-24 to prepare like a pro:

• Time yourself: When you solve the sample paper, time yourself to see how long it takes you to complete it. This will help you to identify the areas where you need to improve your speed and accuracy.
• Mark your mistakes: After you have solved the sample paper, mark your mistakes. This will help you to identify the topics that you need to revise and to practice more.
• Use the solutions: The solutions to the sample paper are a valuable resource. Use them to understand the correct way to answer the questions and to avoid common mistakes.
• Discuss the sample paper with your friends and classmates: Discussing the sample paper with your friends and classmates is a great way to learn from each other and to clarify any doubts that you may have.

By following these tips, you can use the CBSE Class 10 Science Sample Paper 2023-24 to prepare like a pro and to achieve top marks in your board exams.

Note: In case you have doubt in any question or need an explanation of the answer, do comment below. I will be more than happy to help. 😊😊

Class	10
Subject	Science
Content	Official Sample Paper with Solutions
Session	2023-24
Board	CBSE (useful for State Boards also)

CBSE Class 10 Science Official Sample Paper for 2023-24

General Instructions:

i. This question paper consists of 39 questions in 5 sections. ii. All questions are compulsory. However, an internal choice is provided in some questions. A student is expected to attempt only one of these questions. iii. Section A consists of 20 objective-type questions carrying 1 mark each. iv. Section B consists of 6 Very Short questions carrying 02 marks each. Answers to these questions should be in the range of 30 to 50 words. v. Section C consists of 7 Short Answer type questions carrying 03 marks each. Answers to these questions should be in the range of 50 to 80 words. vi. Section D consists of 3 Long Answer type questions carrying 05 marks each. Answers to these questions should be in the range of 80 to 120 words. vii. Section E consists of 3 source-based/case-based units of assessment of 04 marks each with sub-parts.

Section-A Select and write the most appropriate option out of the four options given for each of the questions 1 - 20. There is no negative mark for incorrect response.

Q. No. 1)

Identify the product that represents the solid state in the above reaction.
a) Barium chloride
b) Barium sulphate
c) Sodium chloride
d) Sodium sulphate

Ans. Option (b)

Q. No. 2) The color of the solution observed after 30 minutes of placing zinc metal to copper sulphate solution is
a) Blue
b) Colourless
c) Dirty green
d) Reddish Brown

Ans. Option (b)

Q. No. 3) Mild non-corrosive basic salt is
a) Ca(OH)₂
b) NaCl
c) NaOH
d) NaHCO₃

Ans. Option (d)

Q. No. 4) On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colorless gas is produced when a burning match stick is brought near it. Which of the following correctly represents the metal ‘X’?
a) Sodium
b) Sulphur
c) Copper
d) Silver

Ans. Option (a)

Q. No. 5) Which one of the following correctly represents Sodium oxide?

Ans. Option (b)

Q. No. 6) An element with atomic number_____ will form a basic oxide.
a) 7 (2,5)
b) 17 (2,8,7)
c) 14 (2,8,4)
d) 11 (2,8,1)

Ans. Option (d)

Q. No. 7) An element ‘M' has 50% of the electrons filled in the 3rd shell as in the 2nd shell. The atomic number of ‘M’ is:
a) 10
b) 12
c) 14
d) 18

Ans. Option (c)

Q. No. 8) Generally food is broken and absorbed within the body of organisms. In which of the following organisms is it done outside the body?
a) Amoeba
b) Mushroom
c) Paramoecium
d) Lice

Ans. Option (b)

Q. No. 9) Receptors are usually located in sense organs. Gustatory receptors are present in
a) tongue
b) nose
c) eye
d) ear

Ans. Option (a)

Q. No. 10) A farmer wants to grow banana plants genetically similar enough to the plants already
available in his field. Which one of the following methods would you suggest for this purpose?
a) Regeneration
b) Budding
c) Vegetative propagation
d) Sexual reproduction

Ans. Option (c)

Q. No. 11) The height of a plant is regulated by:
a) DNA which is directly influenced by growth hormone.
b) Genes that regulate the proteins directly.
c) Growth hormones under the influence of the enzymes coded by a gene.
d) Growth hormones directly under the influence of a gene.

Ans. Option (c)

Q. No. 12) A sportsman, after a long break from his routine exercise, suffered muscular cramps during a heavy exercise session. This happened due to:
a) lack of carbon dioxide and formation of pyruvate.
b) presence of oxygen and formation of ethanol.
c) lack of oxygen and formation of lactic acid.
d) lack of oxygen and formation of carbon dioxide.

Ans. Option (c)

Q. No. 13) An object is placed in front of a convex mirror. Its image is formed:
a) at a distance equal to the object's distance in front of the mirror.
b) at twice the distance of the object in front of the mirror.
c) half the distance of the object in front of the mirror.
d) behind the mirror and its position varies according to the object's distance

Ans. Option (d)

Q. No. 14) When light enters the atmosphere it strikes extremely fine particles, which deflect the rays of light in all possible directions, This is due to -
a) reflection of light
b) atmospheric refraction
c) scattering of light
d) dispersion of light

Ans. Option (c)

Q. No. 15) In 1987, an agreement was formulated by the United Nations Environment Programme (UNEP) to freeze the production of “X” to prevent the depletion of “Y”. “X” and “Y” respectively referred here are:
a) Ozone; CFCs
b) CFCs; rays UV
c) CFCs; Ozone
d) UV rays; Diatomic oxygen

Ans. Option (c)

Q. No. 16) Which of the following features relates to biodegradable substances?
a) Broken down by biological processes
b) Remain inert
c) Persist in the environment for a long time
d) May harm the ecosystem

Ans. Option (a)

Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer these questions by selecting the appropriate option given below:
a) Both A and R are true, and R is the correct explanation of A.
b) Both A and R are true, and R is not the correct explanation of A.
c) A is true but R is false.
d) A is false but R is true.

Q. No. 17) Assertion: Rusting of Iron is endothermic in nature.
Reason: As the reaction is slow, the release of heat is barely evident.

Ans. Option (d)

Q. No. 18) Assertion: The probability of survival of an organism produced through sexual reproduction is more than that of an organism produced through asexual mode.
Reason: Variations provide advantages to individuals for survival.

Ans. Option (a)

Q. No. 19) Assertion: A compass needle is placed near a current-carrying wire. The deflection of the compass needle decreases when the magnitude of the current in the wire is increased.
Reason: The strength of a magnetic field at a point near the conductor increases by increasing the current.

Ans. Option (d)

Q. No. 20) Assertion: Biodegradable substances result in the formation of compost and natural replenishment.
Reason: It is due to the breakdown of complex inorganic substances into simple organic substances.

Ans. Option (c)

Section-B Questions No. 21 to 26 are very short answer questions

Q. No. 21) "Dil. HCl is added to Zn granules.” How will you prove that chemical change has taken place here? Support your response with two arguments. (02 marks)

Ans.

• Bubbles of gas/ Evolution of gas
• Change in color (Zn - silvery grey to black)
• Change in temperature.

Q. No. 22) State the post-fertilization changes that lead to fruit formation in plants. (02 marks)

Ans.

• After fertilization, the zygote divides several times to form an embryo within the ovule.
• The ovule develops a tough coat and is gradually converted into a seed.
• The ovary grows rapidly and ripens to form a fruit.
• The petals, sepals, stamens, style, and stigma may shrivel and fall off.

Q. No. 23) What is the purpose of making urine in the human body? Name the organs that store and release the urine. (02 marks)

Ans. To filter out nitrogenous waste products like urea and uric acid from the blood in humans.
Organ for storage: Urinary Bladder
Organ for release: Urethra

OR

Why do arteries have thick and elastic walls whereas veins have valves? (02 marks)

Ans.

• The blood emerges from the heart under high pressure and flows through arteries. Hence, to bear this pressure the arteries have thick and elastic walls.
• Veins have valves to ensure that the blood flows in one direction only.

Q. No. 24) The refractive indices of three media are given below:

Medium	Refractive Index
A	1.6
B	1.8
C	1.5

A ray of light is traveling from A to B and another ray is traveling from B to C.
(a) In which of the two cases the refracted ray bends towards the normal?
(b) In which case does the speed of light increase in the second medium?
Give reasons for your answer. (02 marks)

Ans. a. When light travels from an optically rarer medium to an optically denser medium it moves towards the normal. Since n_B > n_A the light ray will bend towards the normal on passing from medium A to B.

b. The speed of the light will increase when the light travels from B to C. Since n_C<n_B and v=(^c/_n), the speed of the light ray will increase in the second medium.

Q. No. 25) A piece of wire of resistance R is cut into three equal parts. These parts are then connected in parallel. If the equivalent resistance of this parallel combination is R₁, what is the value of the ratio R₁: R? (02 marks)

Ans. The resistance of each part is ^𝑅/₃ Ω (as resistance is proportional to the length of the wire.)

OR

Refer to the image below and state how the magnetic field pattern indicates regions where the magnetic field is stronger outside the magnet. What happens to the magnetic field when the current in the circuit is reversed? (02 marks)

Ans. The magnetic field strength is higher in the region where the field lines are crowded. This means the field strength is maximum near the poles and it reduces as we go away from the poles.

The direction of the magnetic field is also reversed.

Q. No. 26) Study the food chain given below and answer the questions that follow:

a) If the amount of energy available at the third trophic level is 100 joules, then how much energy will be available at the producer level? Justify your answer.
b) Is it possible to have 2 more trophic levels in this food chain just before the fourth trophic level? Justify your answer. (02 marks)

Ans. a) 10000J because only 10 % of energy is available for the next trophic level.
b) No, since the loss of energy at each step is so great that very little usable energy will remain after 4 trophic levels.

Section-C Question No. 27 to 33 are short answer questions

Q. No. 27) The given reaction shows one of the processes to extract metals like Iron and Manganese.

MnO₂ (s) + Al(s) → Mn(l) + Al₂O₃(s) + Heat

a) Give the reason why the above reaction is known as a thermite reaction.
b) Identify the substance oxidized and reduced in the above reaction.
c) Give a reason why Aluminium is preferably used in thermite reactions. (03 marks)

Ans. a) The above reaction is known as a thermite reaction as the reaction is a highly exothermic reaction.
OR
the metal (Mn/Fe) obtained will be in a molten/ liquid state.
b) Substance oxidized - Al(s)
Substance reduced – MnO₂ (s)
c) Aluminium is preferably used in thermite reactions as it is placed above Fe and Mn in the reactivity series of metals.
OR
Al is more reactive than Fe/ Mn.

Q. No. 28) An element ‘M’ with electronic configuration 2 8 3 combines separately with Cl^-, SO4^-2 anions. Write the chemical formulae of the compounds formed. Predict with the suitable reason the nature of the bond formed by element ‘M’ in general. How will the electrical conductivity of the compounds formed vary with respect to ‘M’? (03 marks)

Ans.

• MCl₃; M₂(SO₄)₃
• M in general forms Ionic bond. It can acquire a stable electronic configuration of neon (2, 8) by losing its three valence electrons to form M³⁺cation.
• Compounds formed will conduct electricity in liquid / molten state but not in solid state in contrast to ‘M’.

OR

A reddish-brown metal ‘X’, when heated in air, gives a black compound ‘Y’, which when heated in the presence of H₂ gas gives ‘X’ back. ‘X’ is refined by the process of electrolysis; this refined form of ‘X’ is used in electrical wiring.
Identify ‘X’ and ‘Y’. Draw a well-labeled diagram to represent the process of refining ‘X’. (03 marks)

Ans.

a) ‘X’ - Copper/ Cu and ‘Y’ - CuO
b) Diagram to represent the process of refining ‘X

Q. No. 29) We are advised to take iodized salt in our diet by doctors. Justify it's importance in our
body. (03 marks)

Ans.

• Iodine is essential for the synthesis of thyroxin hormone.
• Thyroxin regulates carbohydrate, protein, and fat metabolism in the body.
• Thyroxin provides the best balance for growth in the body.

Q. No. 30) What is the probability of a girl or a boy being born in a family? Justify your answer. (03 marks)

Ans. There are 50% chance that a girl may be born and a 50% chance that a boy may be born.

It can be explained as follows:

• Most human chromosomes have a maternal copy and a paternal copy. We have 22 such chromosomes. One pair of chromosomes called sex chromosomes is odd in not always being a perfect pair. Women have a perfect pair of sex chromosomes, both called X. (XX)
• But men have a mismatched pair of sex chromosomes in which one is a normal-sized – X chromosome while the other is a short one called a Y chromosome. (XY)
• A child receives one chromosome from the mother which is essentially the X chromosome.
• A child who inherits an X chromosome from her father will be a girl, and one who inherits a Y chromosome from him will be a boy.

Q. No. 31) (i) Explain why the refractive index of any material with respect to air is always greater 1.
(ii) In the figure below a light ray travels from air into the semi-circular plastic block. Give a reason why the ray does not deviate at the semi-circular boundary of the plastic block.

(iii) Complete the ray diagram of the above scenario when the light ray comes out of the plastic block from the top flat end. (03 marks)

Ans.

Q. No. 32) (i) State the law that explains the heating effect of current with respect to the measurable properties in an electrical circuit.
(ii) List the factors on which the resistance of a conductor depends. (03 marks)

Ans. i. Joule's law of heating states that the heat dissipated across a resistor is directly proportional to:
(a) the square of the current flowing through it
(b) The resistance of the conductor
(c) duration of flow of current.

H= I²𝑅𝑡 (alternative answer).

ii. Resistance of a conductor depends on

1. the length of the conductor
2. the area of the cross-section
3. nature of material
4. temperature of the conductor.

Q. No. 33) Anannya responded to the question: Why do electrical appliances with metallic bodies are connected to the mains through a three-pin plug, whereas an electric bulb can be connected with a two-pin plug?
She wrote: Three-pin connections reduce heating of connecting wires.
(i) Is her answer correct or incorrect? Justify.
(ii) What is the function of a fuse in a domestic circuit? (03 marks)

Ans. (i) Anannya’s answer is wrong. Electrical appliances with metallic bodies need an earth wire which provides a low resistance conducting path to the flow of current, in case there is an accidental leakage of current through the conducting body of the appliances.

(ii) An electrical fuse is a safety device that operates to provide protection against the overflow of current in an electrical circuit. An important component of an electrical fuse is a metal wire or strip that melts when excess current flows through it.

Section-D Question No. 34 to 36 are long answer questions.

Q. No. 34) a) Rehmat classified the reaction between Methane and Chlorine in the presence of sunlight as a substitution reaction. Support Rehmat’s view with suitable justification and illustrate the reaction with the help of a balanced chemical equation.
b) Chlorine gas was prepared using electrolysis of brine solution. Write the chemical equation to represent the change. Identify the other products formed in the process and give one application of each. (05 marks)

Ans. a) Rehmat’s observation is correct as the hydrogen atoms are substituted by hetero atom i.e., Cl.
CH4 + Cl2 → CH₃Cl + HCl (in the presence of sunlight)
OR
Any other relevant equation in the chain reaction
2NaCl(aq) + 2H₂O(l) → 2NaOH(aq) + Cl₂ (g) + H₂ (g)
OR
NaCl → Na⁺ + Cl^-.
2Cl^-→ Cl₂ + 2e^- (At anode)
H₂O → H⁺ + OH^-
2H⁺ + 2e → H₂ (At cathode)
Na⁺ + OH^- → NaOH

b) Sodium hydroxide/ NaOH/ Caustic soda
Hydrogen

Uses: Sodium hydroxide/ NaOH/ Caustic soda

• Degreasing of metals
• Preparation of soaps and detergents
• Papermaking
• Artificial fibres

Hydrogen -

• Fuels
• Margarine
• Manufacture of ammonia for fertilizers

OR

Raina while doing certain reactions observed that heating of substance ‘X’ with a vinegar-like smell with a substance ‘Y’ (which is used as an industrial solvent) in the presence of conc. Sulphuric acid in a water bath gives a sweet-smelling liquid ‘Z’ having molecular formula C₄H₈O₂. When heated with caustic soda (NaOH), ‘Z’ gives back the sodium salt and the compound ‘Y’.

Identify ‘X’, ‘Y’, and ‘Z’. Illustrate the changes with the help of suitable chemical equations. (05 marks)

Ans. X - Ethanoic acid/ acetic acid/ CH₃COOH
Y - Ethanol/ Ethyl alcohol/ C₂H₅OH
Z - Ethyl ethanoate/ Ester – CH₃COOC₂H₅

Q. No. 35) Given below are certain situations. Analyze and describe its possible impact on a person:
a) Testes of a male boy are not able to descend into the scrotum during his embryonic development.
b) Vas deferens of a man is plugged.
c) Prostate and seminal vesicles are not functional.
d) Egg is not fertilized in a human female.
e) Placenta does not attach to the uterus optimally. (05 marks)

Ans.

a) Sperm formation will be adversely affected because it requires a lower temperature than the body temperature.
b) Vas deferens is a passage for transfer of sperms, so sperms will not be transferred further.
c) When the prostate and seminal vesicles are not functional, they will not add secretions for nourishment and medium for the transport of sperm.
d) When an egg is not fertilized in a human female, it lives for about one day. Then, the thickened lining of the uterus breaks leading to the discharge of blood and mucus along with the unfertilized egg. This is called menstruation.
e) Nutrition and oxygen will not be provided to the growing embryo affecting its growth, which could have serious implications as well.

OR

a) A doctor has advised Sameer to reduce sugar intake in his diet and do regular exercise after checking his blood test reports. Which disease do you think Sameer is suffering from? Name the hormone responsible for this disease and the organ producing the hormone.
b) Which hormone is present in the areas of rapid cell division in a plant and which hormone inhibits the growth? (05 marks)

Ans. a) Sameer is suffering from diabetes

• Insulin
• Pancreas

b)

• Cytokinins
• Abscisic Acid

Q. No. 36)

The above image shows a thin lens of focal length 5 m.
(i) What is the kind of lens shown in the above figure?
(ii) If a real inverted image is to be formed by this lens at a distance of 7m from the optical centre, then show with calculation where should the object be placed.
(iii) Draw a neatly labeled diagram of the image formation mentioned in (ii). (05 marks)

Ans. i. Convex lens

ii. ¹/_f = ¹/_v - ¹/_u

In this case, v= 7m and f=5m.
Putting the values in the equation we get,

The object will be placed 17.5 m on the left of the convex lens.

iii.

OR

A 10 cm long pencil is placed 5 cm in front of a concave mirror having a radius of curvature of 40 cm.(i) Determine the position of the image formed by this mirror.
(ii) What is the size of the image?
(iii) Draw a ray diagram to show the formation of the image as mentioned in the part (i). (05 marks)

Ans. i.

The image is obtained at 6.67 cm behind the mirror.

ii. m = ^h'/_h = - ^v/_u = - ^20/3/_-5 = 4/3

⇒ h'/10 = 4/3

⇒ h' = 40/3 cm

iii.

SECTION - E Questions No. 37 to 39 are case-based/data-based questions with 2 to 3 short sub-parts. Internal choice is provided in one of these sub-parts.

Q. No. 37) The table given below shows the hints given by the quiz master in a quiz.

S.No.	HINT
i.	Substance ‘C’ is used as a preservative.
ii.	‘C’ has two carbon atoms; ‘C’ is obtained by the reaction of ‘A’ in the presence of alkaline Potassium permanganate followed by acidification.
iii.	Misuse of ‘A’ in industries is prevented by adding Methanol, Benzene, and pyridine to ‘A’.
iv.	‘F’ is formed on heating ‘A’ in the presence of conc Sulphuric acid.
v.	‘F’ reacts with Hydrogen gas in the presence of Nickel and Palladium catalysts.

Based on the above hints answer the following questions
a) Give the IUPAC names of A and F
b) Illustrate with the help of chemical equations the changes taking place. (A → C and A → F)
OR
Name the chemical reactions which occur in steps 2 and 5. Identify the compounds formed in these steps if ‘A’ is replaced with its next homologue. (04 marks)

Ans. a) A - Ethanol; F - Ethene

b) A → C

A → F

OR

Oxidation, Addition/ Hydrogenation
Propanol, Propene.

Q. No. 38) Figures (a) to (d) given below represent the type of ear lobes present in a family consisting of 2 children – Rahul and Nisha, and their parents.

Excited by his observation of different types of ear lobes present in his family, Rahul conducted a survey of the type of ear lobes found {Figure (e) and (f)} in his classmates. He found two types of ear lobes in his classmates as per the frequency given below:

Sex	Free	Attached
Male	36	14
Female	31	19

On the basis of the above data answer the following questions.
a) Which of the two characteristics - ‘free ear lobe’ or ‘attached ear lobe’ appears to be dominant in this case? Why?
b) Is the inheritance of the free ear lobe linked with the sex of the individual? Give a reason for your answer.
c) What type of ear lobe is present in father, mother, Rahul, and his sister Nisha? Write the genetic constitution of each of these family members which explains the inheritance of this character in this family.
(The gene for the Free ear lobe is represented by F and the gene for the attached ear lobe is represented by f for writing the genetic constitution).
OR
Suresh’s parents have attached ear lobes. What type of ear lobe can be seen in Suresh and his sister Siya? Explain by giving the genetic composition of all. (04 marks)

Ans.

a) Free ear lobe is dominant because it is found in a large majority of the population.
b) No. It is not sex-linked. As per the data of the family as well as the class, it is indicated that free ear lobe is present in males as well as in females.
c) Father – Ff (free ear lobe), Mother – Ff (free ear lobe), Rahul – ff (attached ear lobe) and Nisha – Ff (free ear lobe)
OR
Suresh’s father – ff (attached ear lobe), mother – ff (attached ear lobe), Suresh - ff (attached ear lobe), Siya – ff (attached ear lobe). If both parents have recessive characters, then all the children can have recessive characters only.

Q. No. 39) Vinita and Ahmed demonstrated a circuit that operates the two headlights and the two sidelights of a car, in their school exhibition. Based on their demonstrated circuit, answer the following questions.

(i) State what happens when switch A is connected to

a) Position 2
b) Position 3

(ii) Find the potential difference across each lamp when lit.

(iii) Calculate the current

a. In each 12 Ω lamp when lit.
b. In each 4 Ω lamp when lit.

OR

(iv) Show, with calculations, which type of lamp, 4.0 Ω or 12 Ω, has the higher power. (04 marks)

Ans. (i) a. 12 Ω lamps (only) on.

b. 4 Ω lamps (only) on.

(ii) 12 V for both sets of lamps and all of them are in parallel.

(iii) a. 12 Ω lamps are on when the wire is connected to position 2.

Voltage across both 12 Ω lamps = 12 V.

V=IR (Ohm’s law)

⇒ I = V/R

⇒ I = 12/12 = 1 A.

a. 4 Ω lamps are on when the wire is connected to position 3.

Voltage across both 4 Ω lamps = 12 V.

V=IR (Ohm’s law)

⇒ I = V/R

⇒ I = 12/4 = 3A.

(iv) P = V²/R

All lamps are in parallel and hence the same V for all lamps.

For 4 Ω lamps → P = ^12×12/₄ = 36 W

For 12 Ω lamps → P = ^12×12/₁₂ = 12 W

Hence 4 Ω lamps will have higher power.

Also See: Class 10 Social Science Official Sample Paper for 2023-24 Board Exams