CBSE Class 10 Science Sample Paper 2023-24 With Answers

The CBSE Class 10 Science Sample Paper 2023-24 is designed according to the latest competency-based exam pattern issued by the board. It includes a balanced mix of objective, short answer, long answer, and case-based questions to assess conceptual understanding and application skills.

CBSE Class 10 Science Sample Paper 2023-24 – Solved

Sample Question Paper 2023-24
Class X
Science (Subject Code – 086)

Max. Marks: 80 Time Allowed: 3 hours

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. Answer 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 (1 mark each)

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

1.

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

Answer: b) Barium sulphate

Explanation: The reaction between sodium sulphate and barium chloride is a double displacement reaction. It produces sodium chloride (aqueous) and barium sulphate, which forms as a white insoluble precipitate (solid).

2. The colour 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

Answer: b) Colourless

Explanation: Zinc is more reactive than copper and displaces it from the copper sulphate solution. The blue colour of copper sulphate fades as colourless zinc sulphate is formed.

3. Mild non-corrosive basic salt is
a) Ca (OH)2
b) NaCl
c) NaOH
d) NaHCO3

Answer: d) NaHCO3

Explanation: NaHCO3 (Sodium Hydrogen Carbonate or Baking Soda) is a mild, non-corrosive basic salt often used as an antacid. Ca(OH)2 and NaOH are bases (alkalis), not salts, and NaCl is a neutral salt.

4. On adding dilute sulphuric acid to a test tube containing a metal ‘X’, a colourless gas is
produced when a burning match stick is brought near it. Which of the following correctly
represents metal ‘X’?
a) Sodium
b) Sulphur
c) Copper
d) Silver

Answer: a) Sodium

Explanation: The gas produced is Hydrogen (H2), which burns with a “pop” sound when a match is brought near it. For this to occur with dilute acid, the metal must be more reactive than hydrogen. Copper and Silver are less reactive than hydrogen and will not react. Sulphur is a non-metal. Sodium is a reactive metal that displaces hydrogen from acids

5. Which one of the following correctly represents Sodium oxide?

The correct representation of Sodium oxide is 2Na+ [O]2−. This ionic compound is formed when each of the two sodium atoms donates one electron to the oxygen atom.

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)

Answer: d) 11 (2,8,1)

Explanation: Basic oxides are typically formed by metals. The element with atomic number 11 is Sodium (electronic configuration 2, 8, 1). As a metal, it readily loses an electron to form a basic oxide (Na2O). Elements with atomic numbers 7 (Nitrogen), 14 (Silicon), and 17 (Chlorine) are non-metals or metalloids which generally form acidic oxides.

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

Answer: c) 14

Explanation: The 2nd shell can hold a maximum of 8 electrons. If the 3rd shell has 50% of that amount, it holds 4 electrons .

• The configuration is: K=2, L=8, M=4.
• Total atomic number = 2 + 8 + 4 = 14. (This element is Silicon).

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

Answer: b) Mushroom

Explanation: Mushrooms (fungi) exhibit saprophytic nutrition. They break down complex organic matter outside their bodies using enzymes and then absorb the simpler nutrients. Amoeba and Paramecium digest food internally (holozoic nutrition), and Lice are parasites.

9 . Receptors are usually located in sense organs. Gustatory receptors are present in
a) tongue
b) nose
c) eye
d) ear

Answer: a) tongue

Explanation: Gustatory receptors are specialized for the sense of taste and are located on the tongue. (Olfactory receptors are found in the nose for smell).

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

Answer: c) Vegetative propagation

Explanation: Vegetative propagation is a form of asexual reproduction that produces offspring genetically identical to the parent plant (clones). This is the standard method for maintaining specific traits in crops like bananas.

11.Height of a plant is regulated by:
a) DNA which is directly influenced by growth hormone.
b) Genes which regulate the proteins directly.
c) Growth hormones under the influence of the enzymes coded by a gene.
d) Growth hormones directly under the influence a gene.

Answer: c) Growth hormones under the influence of the enzymes coded by a gene.

Explanation: Genes code for specific enzymes (proteins). These enzymes catalyze the reactions that produce growth hormones (like auxin). The amount of hormone produced regulates the height of the plant. If the enzyme is efficient, more hormone is produced, resulting in a taller plant.

12. A sportsman, after a long break of 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.

Answer: c) lack of oxygen and formation of lactic acid.

Explanation: During heavy exercise, when the oxygen supply to muscle cells is insufficient to meet energy needs, glucose breaks down via an anaerobic pathway. This incomplete breakdown produces lactic acid, the accumulation of which causes muscle cramps

13. An object is placed in front of a convex mirror. Its image is formed :
a) at a distance equal to the object 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 it’s position varies according to the object distance.

Answer: d) behind the mirror and its position varies according to the object distance.

Explanation: Convex mirrors always form virtual and erect images located behind the mirror (specifically between the pole and the principal focus). While the image is always diminished, its exact position changes as the object is moved closer to or further from the mirror.

14. When light enters the atmosphere it strikes on 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

Answer: c) scattering of light

Explanation: This phenomenon describes the scattering of light. Fine particles in the atmosphere (like air molecules and dust) interact with light and redirect it in different directions. This is why the sky appears blue

15. In 1987, an agreement was formulated by the United Nations Environment Programme
(UNEP) to freeze the production of “X” to prevent 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

Answer: c) CFCs; Ozone

Explanation: The agreement mentioned is the Montreal Protocol. It mandated freezing the production of Chlorofluorocarbons (CFCs – “X”) to prevent the depletion of the Ozone layer (“Y”), which protects the earth from harmful UV radiation.

16. Which of the following features relates to biodegradable substances?
a) Broken down by biological processes
b) Remain inert
c) Persist in environment for long time
d) May harm the ecosystem

Answer: a) Broken down by biological processes

Explanation: Biodegradable substances are materials that can be decomposed by the action of microorganisms (bacteria and fungi) into simpler substances, unlike non-biodegradable materials which persist in the environment

Question No. 17 to 20 consist of two statements – Assertion (A) and Reason (R). Answer
these questions 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.
17. Assertion (A): Rusting of Iron is endothermic in nature. Reason (R): As the reaction is slow, the release of heat is barely evident.

• Answer: d) A is false but R is true.
• Explanation: Rusting is an oxidation reaction, which is exothermic (releases heat), not endothermic. Therefore, the Assertion is false. The Reason is true; because rusting is a very slow process, the heat released dissipates over time and is not easily noticed.

18. Assertion (A): Probability of survival of an organism produced through sexual reproduction is more than that of organism produced through asexual mode. Reason (R): Variations provide advantages to individuals for survival.

• Answer: a) Both A and R are true, and R is the correct explanation of A.
• Explanation: Sexual reproduction involves the fusion of gametes, leading to genetic variations. These variations allow organisms to adapt better to changing environmental conditions, thereby increasing their chances of survival compared to asexual clones.

19. Assertion (A): 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 (R): The strength of a magnetic field at a point near the conductor increases on increasing the current.

• Answer: d) A is false but R is true.
• Explanation: The Assertion is false because increasing the current increases the strength of the magnetic field (as stated correctly in the Reason). A stronger magnetic field would cause a greater (or stronger) deflection of the compass needle, not a decrease.

20. Assertion (A): Biodegradable substances result in the formation of compost and natural replenishment. Reason (R): It is due to breakdown of complex inorganic substances into simple organic substances.

Explanation: The Assertion is true; biodegradable waste forms compost. However, the Reason is false because decomposition involves the breakdown of complex organic substances into simple inorganic substances (like nutrients, water, and gases), not the other way around.

Answer: c) A is true but R is false.

Section-B

Question No. 21 to 26 are very short answer questions

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.

Ans: When dilute hydrochloric acid (HCl) is added to zinc (Zn) granules, a chemical change takes place. This can be proved by the following two observations:

1. Evolution of Gas:
   Bubbles of hydrogen gas (H₂) are produced during the reaction. The gas can be tested by bringing a burning matchstick near it, which produces a ‘pop’ sound, confirming hydrogen gas formation.
2. Formation of a New Substance:
   Zinc reacts with hydrochloric acid to form a new substance called zinc chloride (ZnCl₂) in solution.

Chemical equation:$$Zn + 2HCl \rightarrow ZnCl_2 + H_2 \uparrow$$

Thus, the formation of hydrogen gas and a new compound (zinc chloride) proves that a chemical change has occurred.

22 State the post-fertilisation changes that lead to fruit formation in plants. 2

After fertilisation, the following post-fertilisation changes occur in plants that lead to fruit formation:

1. Ovary develops into fruit:
   The ovary of the flower enlarges and develops into a fruit, while the ovary wall forms the pericarp (fruit wall).
2. Ovules develop into seeds:
   The fertilised ovules inside the ovary develop into seeds, which contain the embryo.

Thus, after fertilisation, the ovary becomes the fruit and the ovules become seeds.

23 What is the purpose of making urine in the human body? Name the organs that stores and releases the urine.
OR
Why do arteries have thick and elastic walls whereas veins have valves?

Option 1:

Purpose of making urine:
Urine is formed to remove waste products (such as urea, excess salts, and water) from the blood and maintain the balance of fluids in the body.

Organs that store and release urine:

• Urinary bladder – stores urine.
• Urethra – releases urine outside the body.

OR

Reason:

• Arteries have thick and elastic walls because blood flows through them at high pressure from the heart.
• Veins have valves to prevent the backflow of blood since blood flows in them at low pressure back to the heart.

24. The refractive indices of three media are given below:

A ray of light is travelling from A to B and another ray is travelling 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.

Rule:

• Light bends towards the normal when it goes from a rarer medium (lower refractive index) to a denser medium (higher refractive index).
• The speed of light increases when it goes from a denser medium to a rarer medium.

(a) Refracted ray bends towards the normal:
The ray bends towards the normal when travelling from A to B, because the refractive index of B is greater than that of A (light goes from rarer to denser medium).

(b) Speed of light increases in the second medium:
The speed of light increases when the ray travels from B to C, because the refractive index of C is less than that of B (light goes from denser to rarer medium).

Thus,

• Towards normal: A → B
• Speed increases: B → C.

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?
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?

Answer:

Option 1:

A wire has resistance R. When it is cut into three equal parts, the resistance of each part becomes:$$\frac{R}{3}$$3R​

These three resistors are connected in parallel.

For three equal resistances in parallel:$$\frac{1}{R_1} = \frac{1}{R/3} + \frac{1}{R/3} + \frac{1}{R/3}$$$$\frac{1}{R_1} = \frac{3}{R} + \frac{3}{R} + \frac{3}{R} = \frac{9}{R}$$$$R_1 = \frac{R}{9}$$

Therefore,$$R_1 : R = \frac{R}{9} : R = 1 : 9$$

OR

The magnetic field is stronger in regions where the field lines are closer together (more crowded) outside the magnet. This indicates a stronger magnetic field.

When the current in the circuit is reversed, the direction of the magnetic field also reverses.

Ans: The magnetic field is stronger where the magnetic field lines are closer together outside the magnet.

When the current in the circuit is reversed, the direction of the magnetic field also reverses.

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.

27. The given reaction shows one of the processes to extract the metals like Iron and Manganese.
MnO₂ (s) + Al(s) → Mn(l) + Al₂O₃(s) + Heat
a) Give reason why the above reaction is known as a thermite reaction.
b) Identify the substance oxidised and reduced in the above reaction.
c) Give a reason why Aluminium is preferably used in thermite reactions.

The reaction is:$$\text{MnO}_2 (s) + Al(s) \rightarrow Mn(l) + Al_2O_3(s) + \text{Heat}$$

a) Reason why it is called a thermite reaction:
It is called a thermite reaction because aluminium reduces a metal oxide and the reaction produces a large amount of heat, which is sufficient to produce the metal in molten form.

b) Substance oxidised and reduced:

• Aluminium (Al) is oxidised because it combines with oxygen to form Al₂O₃.
• Manganese dioxide (MnO₂) is reduced because it loses oxygen to form Mn.

c) Reason aluminium is used in thermite reactions:
Aluminium is used because it has a high affinity for oxygen and acts as a strong reducing agent, releasing a large amount of heat during the reaction.

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’?

OR

A reddish-brown metal ‘X’, when heated in air, gives a black compound ‘Y’, which when heated in 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’.

Answer: Option 1

Element M has electronic configuration 2, 8, 3, so its valency is 3 (it loses three electrons to form M³⁺).

(a) Chemical formulae of the compounds formed:

• With Cl⁻:
  $M^{3+}$M3+ combines with three $Cl^-$Cl− ions.
  Formula: MCl₃
• With SO₄²⁻:
  Charges must balance.
  Formula: M₂(SO₄)₃

(b) Nature of bond:
The bond formed by element M is mainly ionic (electrovalent) because it loses electrons to form a positive ion (M³⁺) which combines with negative ions.

(c) Electrical conductivity:

• Element M (a metal) conducts electricity in solid state.
• The ionic compounds formed conduct electricity only in molten or aqueous solution because ions become free to move.

OR

Identification:

• X = Copper (Cu)
• Y = Copper(II) oxide (CuO) (black compound)

Reactions:

1. Heating copper in air:

$$2Cu + O_2 \rightarrow 2CuO$$

2. Reduction with hydrogen:

$$CuO + H_2 \rightarrow Cu + H_2O$$

Copper is refined by electrolytic refining and the pure copper is used in electrical wiring.

Diagram of Electrolytic Refining of Copper:

29. We are advised to take iodised salt in our diet by doctors. Justify it’s importance in our body.

Ans: Doctors advise the use of iodised salt because iodine is essential for the proper functioning of the thyroid gland. Iodine is required for the production of the hormone thyroxine, which regulates growth, metabolism, and development of the body.

If the body lacks iodine, it can lead to iodine deficiency disorders such as goitre (swelling of the neck due to enlarged thyroid gland) and may also affect mental development in children.

Therefore, using iodised salt helps prevent iodine deficiency and keeps the thyroid gland functioning properly.

30 What is the probability of a girl or a boy being born in a family? Justify your answer.

31 (i) Explain why the refractive index of any material with respect to air is always greater
(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.

Ans:

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.

Ans: (i) The law that explains the heating effect of current is Joule’s Law of Heating.

It states that the heat produced in a conductor due to electric current is directly proportional to the square of the current, the resistance of the conductor, and the time for which the current flows.

Mathematically:
H = I² R t

Where
H = heat produced
I = current
R = resistance
t = time

(ii) Factors on which the resistance of a conductor depends

Temperature of the conductor – Resistance generally increases with increase in temperature.

Length of the conductor – Resistance increases with increase in length.

Area of cross-section – Resistance decreases when the cross-sectional area increases.

Nature of the material – Different materials have different resistivities.

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?

Ans: (i) Anannya’s answer is incorrect.

Justification:
Electrical appliances with metallic bodies are connected through a three-pin plug to provide earthing. The third pin is the earth wire, which protects the user from electric shock. If there is leakage of current, the excess current flows to the earth, preventing the metallic body from becoming live.

An electric bulb usually has a non-metallic (insulated) outer covering, so it does not require an earth connection and can be connected using a two-pin plug.

(ii) Function of a fuse in a domestic circuit

A fuse is a safety device that protects electrical circuits and appliances from damage due to excessive current or short circuit.

It contains a thin wire of low melting point which melts and breaks the circuit when the current exceeds the safe limit. This stops the flow of electricity and prevents overheating or fire.

Section-D

Question No. 34 to 36 are long answer questions.
34 a) Rehmat classified the reaction between Methane and Chlorine in 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.

OR

Raina while doing certain reactions observed that heating of substance ‘X’ with vinegar like smell with a substance ‘Y’ (which is used as an industrial solvent) in presence of conc. Sulphuric acid on 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 of and the compound ‘Y’.
Identify ‘X’, ‘Y’, and ‘Z’. Illustrate the changes with the help of suitable chemical equations.

Ans: Option 1

a) Justification of substitution reaction

A substitution reaction is a reaction in which one atom or group of atoms in a molecule is replaced by another atom or group.

In the reaction between methane and chlorine in the presence of sunlight, one hydrogen atom of methane is replaced by a chlorine atom. Therefore, it is called a substitution reaction.

Balanced chemical equation:$$CH_4 + Cl_2 \xrightarrow{sunlight} CH_3Cl + HCl$$

Here, one hydrogen atom of methane is substituted by chlorine to form chloromethane (CH₃Cl).

b) Electrolysis of brine

When brine solution (aqueous NaCl) is electrolysed, chlorine gas is produced at the anode.

Chemical equation:$$2NaCl(aq) + 2H_2O(l) \rightarrow 2NaOH(aq) + Cl_2(g) + H_2(g)$$

Other products formed:

1. Hydrogen gas (H₂)
2. Sodium hydroxide (NaOH)

Applications:

• Hydrogen gas: Used in the manufacture of ammonia and hydrogenation of oils.
• Sodium hydroxide: Used in making soaps, detergents, paper, and textiles.

OR

This reaction represents esterification.

Identification:

• X: Ethanoic acid (CH₃COOH)
• Y: Ethanol (C₂H₅OH)
• Z: Ethyl ethanoate (C₄H₈O₂) — a sweet-smelling ester

Esterification reaction:$$CH_3COOH + C_2H_5OH \xrightarrow{conc.\ H_2SO_4} CH_3COOC_2H_5 + H_2O$$

Ethanoic acid reacts with ethanol in the presence of concentrated sulphuric acid to form ethyl ethanoate (Z) and water.

Reaction with NaOH (alkaline hydrolysis):$$CH_3COOC_2H_5 + NaOH \rightarrow CH_3COONa + C_2H_5OH$$

Thus, ethyl ethanoate (Z) reacts with NaOH to give sodium ethanoate and ethanol (Y).

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 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 fertilised in a human female.
e) Placenta does not attach to the uterus optimally.

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?

Ans: Option 1

a) Testes do not descend into the scrotum:
If the testes do not descend into the scrotum during development, sperm production may be affected because the scrotum provides a lower temperature necessary for sperm formation, which may lead to infertility.

b) Vas deferens is plugged:
If the vas deferens is blocked, sperms cannot travel from the testes to the urethra. Therefore, sperms will not be present in semen, preventing fertilisation.

c) Prostate and seminal vesicles are not functional:
These glands produce fluids that nourish sperms and help in their transport. If they are not functional, semen formation is affected and sperm motility decreases, reducing chances of fertilisation.

d) Egg is not fertilised in a human female:
If the egg is not fertilised, the uterine lining breaks down and is shed, leading to menstruation.

e) Placenta does not attach properly to the uterus:
If the placenta is not properly attached, the foetus may not receive enough nutrients and oxygen, which can cause poor development or miscarriage.

OR

a)
Sameer is likely suffering from Diabetes mellitus.

• Hormone responsible: Insulin
• Organ producing the hormone: Pancreas

Insulin controls the level of glucose in the blood. Lack or improper action of insulin leads to increased blood sugar levels.

b)

The hormone that inhibits plant growth is Abscisic acid (ABA).

The hormone present in areas of rapid cell division in plants is Cytokinin.

36.

The above image shows a thin lens of focal length 5m.
(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 labelled diagram of the image formation mentioned in (ii)

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).

Ans:

Given:
Length of object (pencil) h = 10 cm
Object distance u = –5 cm (object in front of mirror)
Radius of curvature R = 40 cm

Focal length of concave mirror:$$f = \frac{R}{2} = \frac{40}{2} = 20 \, cm$$

For concave mirror f = –20 cm

(i) Position of the image

Mirror formula:$$\frac{1}{f} = \frac{1}{v} + \frac{1}{u}$$$$\frac{1}{-20} = \frac{1}{v} + \frac{1}{-5}$$$$\frac{1}{-20} = \frac{1}{v} – \frac{1}{5}$$$$\frac{1}{v} = -\frac{1}{20} + \frac{1}{5}$$$$\frac{1}{v} = \frac{3}{20}$$$$v = \frac{20}{3} \approx 6.67 \, cm$$

So, the image is formed 6.67 cm behind the mirror (virtual image).

(ii) Size of the image

Magnification:$$m = \frac{h_i}{h_o} = -\frac{v}{u}$$$$m = -\frac{6.67}{-5} = 1.33$$$$h_i = m \times h_o$$$$h_i = 1.33 \times 10 = 13.3 \, cm$$

So, the image height ≈ 13.3 cm (erect and magnified).

(iii) Ray diagram (description)

• Place the object between the pole (P) and focus (F) of the concave mirror.
• Draw one ray parallel to the principal axis, which reflects through focus (F).
• Draw another ray towards the pole (P) and reflect it obeying the law of reflection.
• Extend the reflected rays behind the mirror where they meet to form a virtual, erect, magnified image.

SECTION – E

Question 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.
37 The table given below shows the hints given by the quiz master in a quiz

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.

38. Figures (a) to (d) given below represent the type of ear lobes present in a family consisting
of 2 children – Rahul, 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:

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 sex of the individual? Give 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?
(Gene for Free ear lobe is represented by F and gene for attached ear lobe is represented
by f for writing the genetic constitution).

OR

Suresh’s parents have attached earl obes. What type of ear lobe can be seen in Suresh
and his sister Siya? Explain by giving the genetic composition of all.

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.

For the official Class 10 Mathematics Solutions, you can visit:

1. NCERT Textbooks (for Class 10):
   

Class-wise Solutions

Class 12:

Class 12 Physics – NCERT Solutions

Class 12 Chemistry – NCERT Solutions

Class 11:

• Class 11 Physics – NCERT Solutions
• Class 11 Chemistry – NCERT Solutions
• Class 11 Biology – NCERT Solutions
• Class 11 Math – NCERT Solutions

Class 10:

• Class 10 Science – NCERT Solutions
• Class 10 Math – NCERT Solutions
• Class 10 Science – CBSE SQP 2024

Class 9:

• Class 9 Science – NCERT Solutions
• Class 9 Math – NCERT Solutions

Class 8:

• Class 8 Science – Oxford Solutions
• Class 8 Science – NCERT Solutions

Class 7:

• Class 7 Science – Oxford Solutions

Class 6:

• Class 6 Science – Oxford Solutions

The CBSE Class 10 Science Sample Paper 2023-24 is a valuable tool for students preparing for their board exams. It not only familiarizes students with the new question pattern but also sharpens their problem-solving and analytical thinking skills. By solving all sections — including objective, case-based, and competency-based questions — students can strengthen their grasp on Physics, Chemistry, and Biology topics in a structured manner.

Moreover, the solutions provided for the CBSE Class 10 Science Sample Paper 2023-24 are explained in simple language, following the NCERT-based approach, which ensures clarity and accuracy. It is highly recommended that students review the marking scheme and answer structure through these solved examples to maximize their performance in the actual exam.

In conclusion, the CBSE Class 10 Science Sample Paper 2023-24 is more than just a practice resource—it is a complete guide for effective revision and exam strategy. Students who solve it thoroughly and learn from the solutions are more likely to perform well and score higher in their final board examination.