Science 31/5/1 2025-2026 English Medium Class 10 Question Paper Solution

Identify the part that controls the closing and opening of the stomatal pore in leaves of plants.

Select the correct option.

Stomata

Epidermal cells

Guard cells

Chloroplasts

Identify the endocrine gland that regulates the growth of human body.

Pituitary gland

Thyroid gland

Pancreas

Adrenal gland

Choose the equation of reaction that correctly represents anaerobic respiration in muscles:

\[\ce{Glucose -> Pyruvate ->[Absence][of O2] Ethanol + CO2 + Energy}\]

\[\ce{Glucose ->[O2] Pyruvate ->[O2] Energy}\]

\[\ce{Glucose ->[O2] Pyruvate ->[Lack of][oxygen] Ethanol + Energy}\]

\[\ce{Glucose -> Pyruvate ->[Lack of][oxygen] Lactic acid + Energy}\]

In human beings, the implantation of fertilised egg takes place in which part of female reproductive system?

Oviduct

Cervix

Uterus

Vagina

When a human egg is fertilized by a sperm having ‘Y’ chromosome, the zygote has the following combination of chromosomes:

44 + XX

22 + XX

44 + XY

22 + XY

Which of the following is a non-biodegradable pollutant?

Paper

DDT

Wood

Vegetable peel

In an ecosystem, the decomposers perform an important role. Select the option indicating the role of decomposers.

Convert inorganic materials to simpler forms

Break down complex organic substances to simple inorganic substances.

Break down inorganic substances into organic substances.

Do not act on organic compounds.

Assertion (A): Bacteria that can withstand heat have better chances of survival in a heat wave.

Reason (R): Accumulation of variations in a species increases the chances of its survival in changing environment.

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

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.

Assertion (A): The peristaltic movements occur all along the gut.

Reason (R): The lining of the gut has muscles that contract rhythmically to push the food in regulated manner.

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.

Give a diagrammatic representation of nutrition in Amoeba.

Observe the given figure and identify the labelled parts P, Q, R and S:

Which of the plant hormone is responsible for the following process?

Promote cell division

Which of the plant hormone is responsible for the following process?

Inhibition of growth

Which of the plant hormone is responsible for the following process?

Detection of light

Which of the plant hormones is responsible for the following process?

Wilting of leaves

Briefly mention the steps in double-circulation through human heart.

Based on Mendel’s experiment show the cross between round, yellow seeds of pea plant (RRYY) with wrinkled and green seeds of pea plant (rryy) upto F₂ generation. Write the number of seeds/plants with following genetic (Genotype) makeup in F₂ generation:

1. RRYY
2. rryy

Mention any one harmful effect of using plastic bags on the environment. Suggest better alternatives to the usage of plastic bags.

Paddy fields require a large amount of water. The pesticides and chemical fertilizers used are washed down into the soil or waterbodies. How do these chemicals reach our bodies? What is this phenomenon known as?

(a) Write the structure and function of Bowman’s capsule.    [1]

(b) Although kidneys filter a large amount (about 180 L daily) of fluids, still the excretion from the body is only about a litre or two. Why?    [1]

(c) What is excretion? Why is it necessary for any living organism?    [2]

OR

(c) State two similarities between lungs and kidneys.    [2]

In an angiospermic flower, fertilization is said to take place when male gametes carried in the pollen tube fuse with the female gamete, present in the embryo sac. This results in lot of changes in different parts of the flower. State the changes taking place in the following structures of flower post fertilization:

1. Zygote
2. Ovule
3. Ovary
4. Sepals

Define the following:

Germination

1. Sugarcane does not produce seeds so name the process through which it will be able to reproduce.
2. List any two advantages of this method.
3. Besides sugarcane, give two more examples of plants that reproduce by this method.
4. Why regeneration is not possible in all the types of animals?

The volume ratio of hydrogen and oxygen gases liberated during electrolysis of water is ______.

1 : 2

2 : 1

1 : 3

4 : 1

Which of the following set of compounds does not belong to same homologous series?

CH₄ and C₄H₁₀

C₂H₆ and C₃H₈

C₃H₈ and C₅H₁₂

C₄H₈ and C₅H₁₂

Which of the following is an amphoteric oxide?

Na₂O

K₂O

CO₂

Al₂O₃

Study the following table and select the correct option:

Which of the following will not undergo addition reaction?

C₄H₈

C₂H₂

C₃H₈

C₂H₄

Four solutions, namely glucose, alcohol, hydrochloric acid and sulphuric acid filled in four separate beakers are connected one by one in an electric circuit with a bulb. The solutions in which the bulb will glow when current is passed are ______.

Glucose and alcohol

Alcohol and hydrochloric acid

Glucose and sulphuric acid

Hydrochloric acid and sulphuric acid

Which gas is evolved when magnesium metal reacts with very dilute HNO₃?

Oxygen

Nitrogen

Hydrogen

Nitrogen Dioxide

Assertion (A): Reaction of quick lime with water is an exothermic reaction.

Reason (R): A large amount of heat is evolved on the reaction quick lime and water.

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.

Define the following term:

Olfactory indicator

Define the term ‘water of crystallization’.

What happens when lead (II) nitrate is heated?

Write balanced chemical equation of the reaction involved in support of your answer.

What happens when iron (II) sulphate is heated?

Write balanced chemical equation of the reaction involved in support of your answer.

What happens when silver chloride is exposed to sunlight?

Write a balanced chemical equation of the reaction involved in support of your answer.

Give the chemical name and formula of Plaster of Paris.

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

Plaster of Paris

Mention the uses of Plaster of Paris.

Name the acid present in ant’s sting.

Give reason:

While diluting an acid, it is recommended that the acid should be added to water.

Give reason:

Baking soda is used as an antacid.

(a) Write structural formula and name of 4^th member of alcohol homologous series.    [1]

(b) What happens when ethanol is heated with alkaline KMnO₄? Write chemical equation involved.    [1]

(c) Write the chemical equation of reaction of ethanol with ethanoic acid in the presence of concentrated H₂SO₄. Write the name of this reaction.    [2]

OR

(c) What happens when ethanol is heated with excess concentrated sulphuric acid at 443 K? Write chemical equation involved. What is the role of concentrated sulphuric acid in this reaction?    [2]

Give reasons for the following:

Ionic compound have generally high melting points and boiling points.

Give reasons for the following:

Solder, an alloy of lead and tin, is used for welding electrical wires.

Give reasons for the following:

Carbon cannot reduce the oxides of Na or Mg.

The reaction of compound ‘X’ with aluminium is used to join railway tracks:

1. Identify the compound ‘X’.
2. Name the reaction.
3. Write the balanced chemical equation of the reaction of compound ‘X’ with aluminium.

Write the balanced chemical equations when a mixture of Cu₂O and Cu₂S is heated.

Write the balanced chemical equations when ZnS is heated in the presence of oxygen.

Give reasons for the following:

The wires carrying current in homes have a coating of PVC.

Give reasons why copper is used to make hot water tanks and not steel (an alloy of iron).

Show the formation of ionic compound CaO with electron dot structure.

[Atomic number: Ca = 20, O = 8]

Rays from the sun converge at a point 25 cm behind a convex lens. The distance at which an object be placed in front of the lens to get a virtual image, is ______.

20 cm

40 cm

50 cm

More than 50 cm

To restore clear vision in persons whose size of the eye ball has reduced, he/she is suggested to use suitable ______.

Converging lens

Diverging lens

Bifocal lens

Cylindrical lens

Assertion (A): The needle of a compass, kept in an external magnetic field, always aligns itself in the North-South direction of the Earth. 

Reason (R): The behaviour of the needle of the compass is similar to the behaviour of a freely suspended bar magnet.

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

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

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

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

1. Relate the speed of light in the given medium with its optical density.
2. Using the information given in the table below, arrange the medium A, B and C in the ascending order of their optical density.
   

   Medium	Speed of light (m/s)
   A	2.25 × 108
   B	2 × 108
   C	2.08 × 108

How does the change in curvature of the eye lens helps us in the process of seeing the nearby objects clearly?

State the range of the power of accommodation of a normal human eye.

Draw a ray diagram to show the correction of eye defect of an old man who can not see an object placed closer than 1 m from his eye, clearly.

Draw the ray diagram for refraction of light through a glass prism and mark angle of refraction and angle of deviation.

When the path of a light ray refracted through a glass prism is reversed how will the angle of deviation change? Explain.

A ray of light after reflection from a concave mirror becomes parallel to its principal axis. Draw a labelled ray diagram to show this.

What is the difference between virtual images of an object formed by a concave mirror and a convex mirror?

“The value of magnification ‘m’ for a mirror is –2.” Calculate the height of object if the height of image is 20 cm.

Why does an electric bulb become dim when an electric heater in parallel circuit is switched ON?

How to connect three resistors each of resistance 8 Ω, so that the equivalent resistance of the combination is 12 Ω? Draw diagram of the combination and justify your answer.

(a) If the ammeter reading is X ampere with nichrome wire of length ‘l’, then what will be the ammeter reading if the length of nichrome wire is doubled with same area of cross-section?

(b) What happens to the ammeter reading if the area of cross-section of nichrome wire is doubled, keeping the length of wire ‘l’ the same?

(c) Define ‘resistivity’. Write its SI unit. Compare the resistivity of an alloy with its constituents metals.

OR

(c) Give reason:

1. Tungsten is used almost exclusively for making the filament of electric lamps.
2. Conductors of bread-toasters are made of an alloy rather than a pure metal.

Draw a diagram showing the magnetic field lines around a bar magnet.

Write any two characteristics of magnetic field lines.

Write the statement of Right hand thumb rule.

The concentric circles representing the magnetic field around a current carrying straight wire become larger and larger as we move away from the wire. How does magnetic field change on these concentric circles?

Draw a diagram to represent the magnetic field lines along the axis of a current carrying solenoid. Mark arrows to show the direction of current in the solenoid and the direction of magnetic field lines.

Describe some salient features of the magnetic lines of field concept.

What is an electromagnet?

How is an electromagnet made?