Science 31/1/1 2025-2026 English Medium Class 10 Question Paper Solution

Which structure in a leaf is mainly responsible for gaseous exchange?

Xylem

Stomata

Phloem

Cuticle

Identify the type of reproduction shown in the diagram given below:

Budding

Fragmentation

Spore Formation

Binary Fission

Identify the correct statement for spirogyra, leishmania and hydra:

they reproduce sexually.

they are unicellular.

they are multicellular.

they reproduce asexually.

Human brain has various parts or regions that help in different actions, responses and coordination. From the following, identify the part responsible for precision of voluntary actions:

Cerebrum

Cerebellum

Medulla

Pons

Pancreas secretes pancreatic juice which contain certain enzyme that helps in digestion of food.

Choose the correct option from the following:

Trypsin digests emulsified fats and lipase digests proteins.

Trypsin digests proteins and lipase digests emulsified fats.

Trypsin and lipase both digests fats.

Trypsin digests proteins and lipase digests carbohydrates.

Sex is determined by different factors in various species. However, in human beings, it is determined genetically.

Which amongst the following option(s) is/are correct for human beings?

1. Gamete carrying X chromosome from female parent.
2. Gamete carrying X chromosome from male parent.
3. Gamete carrying Y chromosome from male parent.

(ii) and (iii)

(i) only

(i) and (iii)

(iii) only

Which of the following group is not ‘biodegradable’?

Vegetable peels, dead leaves, paper

Cow dung, leather bag, water

Polythene bag, rubber band, ball pen

Paper, fruits, bones

Assertion (A): Reflex actions do not involve thinking.

Reason (R): Most reflex actions are controlled by the spinal cord.

Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (А).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

Assertion (A): In human beings, the respiratory pigment is haemoglobin present in red blood cells.

Reason (R): Haemoglobin has a very high affinity for carbon dioxide.

Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation ofthe Assertion (А).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

What is the function of diaphragm in human respiratory system?

Where is the diaphragm present in the human body?

State two differences between the act of chewing food and salivation on sight of food.

List any two differences between pollination and fertilization.

Draw a neat diagram to show germination of pollen on the female reproductive part of the flower. Name and label only the following parts:

1. The part that receives the pollen grain.
2. The structure that carries the male germ cell to reach the female germ cell.

Given below is a pyramid showing various trophic levels in an ecosystem:

1. From the organisms listed below, identify which one is to be placed at which trophic level?
   Deer, Grass, Lion, Snake, Rabbit
2. Discuss the reason why primary consumers will have more energy as compared to secondary consumers?
3. Why is the base of the pyramid broad?

State the difference between nephron and neuron.

Differentiate between the following pair of terms:

Motor nerve and sensory nerve.

Give difference between the following:

Consumers and decomposers

Answer the following questions:

(a) Why only tall pea plants were observed in F₁ progeny?    [1]

(b) By which method did Mendel obtain F₂ progeny?    [1]

(c) (i) Write one difference between dominant and recessive trait.    [2]

OR

(c) (ii) Write two observations made by Mendel about F₁ progeny.    [2]

Given below is a certain situation. Analyse it and describe its possible impact:

A population of bacteria living in temperate waters whose temperature increased by global warming.

Given below is a certain situation. Analyse it and describe its possible impact:

The sperm encounters the egg when it reaches the oviduct in human females.

Given below is a certain situation. Analyse it and describe its possible impact:

Self pollination does not occur in a flower that contains only pistil.

Given below is a certain situation. Analyse it and describe its possible impact:

Egg does not get fertilised in a human female.

Given below is a certain situation. Analyse it and describe its possible impact:

When the seed is placed under appropriate condition of water and air in the soil?

Given below is a certain situation. Analyse and describe what would happen when:

Spores are liberated from blob-like structures of the bread mould?

What happens when Bryophyllum leaf falls on the wet soil?

Given below is a certain situation. Analyse and describe what would happen when:

A pollen from different species land on the stigma of totally unrelated species?

Given below is a certain situation. Analyse and describe what would happen when:

Copper-T is placed in the uterus of a human female?

Given below are certain situations. Analyse and describe what would happen when:

Spirogyra breaks into smaller fragments upon maturation?

1. \[\ce{AgNO3 + NaCl -> NaNO3 + AgCl}\]
2. \[\ce{K2SO4 + BaCl2 -> BaSO4 + 2KCl}\]

Which of the following options clearly describes both the reactions?

(i) is double displacement, (ii) is displacement reaction.

Both, (i) and (ii) are displacement reactions and precipitation reactions.

Both, (i) and (ii) are double displacement reactions and precipitation reactions.

(i) is displacement, (ii) is double displacement reaction.

Which one of the following can be used as an acid-base indicator by a visually impaired (blind) student?

Turmeric

Vanilla essence

Methyl orange

Litmus

The gases evolved on heating lead (II) nitrate crystals are ______.

NO and O₂

N₂ and NO₂

NO₂ and H₂

NO₂ and O₂

The formula of functional group for aldehyde is ______.

–COOH

–CHO

\[\begin{array}{cc}
\ce{- C -}\\
\phantom{.}||\\
\phantom{.}\ce{O}\\
\end{array}\]

–OH

Which of the following is a poor conductor of electricity?

Pb

Cu

Ag

Al

The natural sources of oxalic acid, lactic acid and methanoic acid respectively are ______.

tomato, curd, ant-sting

tomato, orange, nettle-sting

orange, milk, ant-sting

orange, sour milk, nettle-sting

When an element ‘X’ reacts with water, it starts floating. Identify the element ‘X’:

Potassium

Calcium

Sodium

Iron

Assertion (A): Carbon shares its valence electrons with other atoms of carbon or with atoms of other elements.

Reason (R): The shared electrons belong to the outermost shells of both the atoms and lead to both atoms attaining the noble gas configuration.

Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (А).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

What are amphoteric oxides?

Categorise the following based on their nature:

ZnO, Na₂O, CO₂

Name the substance oxidised and reduced in the following reaction:

\[\ce{ZnO + C -> Zn + CO}\]

Balance the following chemical reaction:

\[\ce{Pb(NO3)2 + KI -> PbI2 + KNO3}\]

Give one example of electrolytic decomposition.

Give one example of decomposition by sunlight.

Explain chlor-alkali process with chemical equation. Name the products formed at anode and cathode.

Write the preparation of the following compound with balanced chemical equation:

Baking Soda

How is bleaching powder prepared? Write a chemical equation of the reaction involved in the preparation of bleaching powder.

Write the preparation of the following compound with balanced chemical equation:

Plaster of Paris

Read the following passage and answer the questions given below:

(a) Why carbonate or sulphide ores are converted to oxides before extraction of metal from it?    [1]

(b) Write a reaction in which Aluminium is used as a reducing agent to obtain metal from its oxide.    [1]

(c) (i) How is copper obtained from its ore (Cu₂S)? Give equations of the reactions.    [2]

OR

(c) (ii) (I) Why highly reactive metals cannot be obtained from their oxides by using carbon as a reducing agent?    [1]

(II) Why solder, an alloy of lead and tin, is used for welding electrical wires together?    [1]

Give reasons for the following:

Covalent compounds are poor conductor of electricity.

Give reasons for the following:

Soap does not form lather in hard water.

Give reasons for the following:

Carbon shows catenation but silicon does not.

Give the balanced chemical equation of the following reaction:

Oxidation of ethanol by acidified potassium dichromate.

Write the chemical equation for the following:

Hydrogenation of ethene.

Mohan heated ethanol with a compound ‘X’ in the presence of a few drops of conc. H₂SO₄ and observed a sweet smelling compound ‘Y’ is formed. When ‘Y’ is treated with sodium hydroxide it gives back ethanol and a compound ‘Z’.

1. Identify ‘X’, ‘Y’ and ‘X’.
2. Write the role of conc. H₂SO₄ in the reaction.
3. Write the chemical equations involved and name the reactions.

A convex lens of focal length 15 cm, is forming a real image. If the size of image is same as the size of object, then position of object and position of inage will be, respectively ______.

−15 cm and −15 cm from lens

–15 cm and +15 cm from lens

–30 cm and +30 cm from lens

–30 cm and –30 cm from lens

When you look at an object very close to your eyes, the ______.

Ciliary muscles of your eye contract and the eye lens becomes thick.

Ciliary muscles of your eye get relaxed and the eye lens becomes thick.

Ciliary muscles of your eye contract and the eye lens becomes thin.

Ciliary muscles of your eye get relaxed and the eye lens becomes thin.

Assertion (A): When rays of white light pass through a prism, on emerging they give spectrum of seven colours.

Reason (R): It is due to the scattering of light that red light bends minimum and violet light bends the maximum.

Both, Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).

Both, Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).

Assertion (A) is true, but Reason (R) is false.

Assertion (A) is false, but Reason (R) is true.

The given figure shows image formation by a lens. Analyse the figure and answer the following questions:

1. What is the type of lens used for image formation in the given ray diagram?
2. If the real image is formed at a distance of 30 cm from the lens and the size of image is twice the size of the object, then where was the object placed?

The resistance of a wire of 0.01 cm radius and 1.0 cm length is 7 Ω. Calculate its resistivity.

An electric heater is rated 220 V; 11 A. Calculate the power consumed if the heater is operated at 200 V.

A person is unable to read a book placed closer than 1 meter from his eyes. Identify the defect of vision in his eyes. Draw the ray diagrams to show the defect of vision and its correction.

Describe an activity to show that a current carrying conductor, placed in an external magnetic field experiences a force.

Imagine that you are sitting in a chamber with your back to one wall. An electron beam, moving horizontally from back wall towards the front wall, is deflected by a strong magnetic field to your right side. What is the direction of magnetic field?

The pattern of magnetic field due to a current carrying wire depends upon the shape made by that wire. Justify.

A current carrying straight wire AB is shown in the given diagram. Out of X, Y and Z on which point will the strength of magnetic field be maximum and why?

Read the following passage and answer the questions given:

(a) A convex lens of focal length 20 cm is used to form an image. If an object is placed at 40 cm from the lens, what will be the position and nature of image?    [1]

(b) Illustrate the formation of image with the help of ray diagram, when the object is placed between the optical centre and principal focus of concave lens.    [1]

(c) (i) A lens combination consists of a convex lens of focal length 30 cm and a concave lens of focal length 15 cm placed together. Find the equivalent focal length and power of this lens combination.    [2]

OR

(c) (ii) Two lenses are placed in contact. One is a concave lens with focal length 2 m and the other is a convex lens with focal length 1.5 m. What type of lens will the combination behave as (convex or concave)? Give reason.    [2]

Due to change in length and area of cross-section of a conductor, resistance of conductor changes while resistivity does not change. Why?

Why are the conductors of electric heating devices, such as bread-toasters and electric irons, made of an alloy rather than a pure metal?

Define the unit of current.

How many bulbs of resistance 8 each should be connected in parallel combination to draw a current of 2 A from a battery of 4 V?

 Which instrument is used to measure electric current? How should it be connected in a circuit?

State Joule’s law of heating.