JKBOSE Class 10th 2025 Science Solved Paper

Note: The below solutions have been prepared in concise language to suit my Govt school children. Plus the answers have been added to respective units wherever necessary.

JKBOSE Class 10th 2025 Annual Regular Science Solved Paper

Section A

Series A

1. Define Radius of curvature of a spherical mirror.

Ans: Radius of Curvature is the distance between Centre of Curvature and the Pole of the spherical mirror.

2. The image formed by a concave mirror is real, inverted and of the same size as the object. What is the position of the object?

Ans: The position of the object is at the Centre of Curvature.

3. The refractive index of Diamond is

(a) 1.77 (b) 1.65 n (c) 2.42 (d) 2.13

Ans: (c) 2.42

4. The S.I unit of Potential difference is

(a) Watt (b) Ampere (c) Volt (d) None of these

Ans: C. Volt

5. Name the device used to measure potential difference across a conductor?

Ans: Voltmeter

6. Which of the following processes involve chemical reaction?

(a) Storing of oxygen under high pressure in a gas cylinder (b) Keeping petrol in a china dish in open air

Ans: (c) Heating copper wire in presence of air at high temperature

7. Food cans are coated with Tin and not with Zinc because

(a) Zinc is costly than Tin (b) Zine has a high melting point than Tin

Ans: (d) Zinc is less reactive than Tin

8. Name two metals, which are mostly found in nature in free native state.

Ans: Gold and Platinum

9. Buckminster fullerene is allotropic form of

(a) Phosphorus (b) Sulphur (c) Carbon (d) Tin

Ans: (c) Carbon

10. The general formula of Alkenes is

(a) CnH2n+2 (b) CnH2n (c) CnH2n-2 (d) None of them

Ans: (b) CnH2n

11. Soil erosion is prevented by:

(a) Overgrazing (b) Removal of vegetation (c) Afforestation (d) Deforestation

Ans: (c) Afforestation

12. The estimated sunlight captured by the green plants in a terrestrial ecosystem is:

(a) 10% (b) 20% (c) 2% (d) 1%

Ans: (a) 10%

13. In a monohybrid cross, we get a Genotypic ratio of

(a) 1:2:1 (b) 1:1:2 (c) 3:1 (d) 2:1:2

Ans: (a) 1:2:1

14. Exchange of genetic material takes place in

(a) Vegetative reproduction (b) Asexual reproduction (C) Sexual reproduction (d) Budding

Ans: (C) Sexual reproduction

15. A zygote which has an x-chromosome inherited from the father will develop into a

(a) Boy (b) Girl (c) X-chromosome doesn't determine the sex of a child

(d) Either boy or girl

Ans: (a) Boy

16. Assertion (A) If a graph is plotted between the current flowing and potential difference, the graph is a straight line passing through the origin.

Reason (R) The current is directly proportional to the potential difference.

Ans: A and R are true and R is the correct explanation of A

17. Assertion (A) If the first member of a homologous series is methanol, its third member will be Ethanol

Reason (R) All the members of a homologous series show similar chemical properties.

Ans: A is false but R is true

18. Assertion (A) Insulin regulates blood sugar level of the body.

Reason (R): Insufficient secretion of Insulin will cause diabetes mellitus.

Ans: A and R are true and R is not the correct explanation of A

Series B

1. No matter how far you stand from a mirror your image appears erect. The mirror is likely to be

(a) Plane (b) Convex (c) Concave (d) Either plane or convex

Ans: (d) Either plane or convex

2. A ray of light passing through optical centre of a concave lens.

(a) bends towards normal (b) bends away from normal (c) doesn't bend at all (d) None of the above

Ans: (c) doesn't bend at all

3. Define one Dioptre of power of a Lens.

Ans: When the focal length of a lens is 1 meter, Its power is said to be one Dioptre.

4. The S.I. unit of resistance is

(a) Ampere (b) Volt (c) Ohm (d) None of the above

Ans: (c) Ohm

5. If we require the maximum resistance from a number of given resistors; we connect.

(a) All in parallels (b) All in series (c) Less resistors in series more in parallels (d) More resistors in series less in Parallel

Ans: (b) All in series

6. Write the balanced chemical equation for the following chemical reaction:

Barium Chloride + Aluminium Sulphate Barium Sulphate + Aluminium Chloride

Ans: BaCl2 + Al2(SO4)3 -> BaSO4 + AlCl3

7. While cooking, if the bottom of the vessel is getting blackened on the outside, it means

(a) The food is not cooked completely (b) The fuel is wet (c) The fuel is not burning completely (d) None of these

Ans: (c) The fuel is not burning completely

8. Ethane with molecular formula, C2H6 has:

(a) 6 covalent bonds (b) 7 covalent bonds (c) 8 covalent bonds (d) 9 covalent bonds

Ans: (b) 7 covalent bonds

9. Give an example of a metal which is liquid at room temperature.

Ans: Mercury (Hg)

10. Give an example of a metal which is poorest conductor of heat.

Ans: Lead (Pb), Mercury (Hg)

11. A cross between a tall pea plant (TT) and short pea plant (tt) resulted in progeny that were all tall plants because.

(a) Tallness is the dominant trait (b) Shortness is the dominant trait (c) Tallness is the recessive trait (d) Height of pea plant is not governed by genes

Ans: (a) Tallness is the dominant trait

12. The number of pair(s) of sex chromosomes in the zygote of humans is

(a) Four (b) Three (c) One (d) None of the above

Ans: (c) One

13. A trait in an organism is influenced by

(a) Paternal DNA only (b) Maternal DNA only (c) Both Paternal and Maternal DNA (d) None of these

Ans: (c) Both Paternal and Maternal DNA

14. Organisms which synthesize carbohydrates from inorganic compounds using radiant energy are called

(a) Decomposers (b) Producers (c) Herbivores (d) Carnivores

Ans: (b) Producers

15. Which of the following can act on Plastics:

(a) Saprophytes (b) Bacteria (c) Pressure (d) Earthworms

Ans: (b) Bacteria

Notes From Q No's 16 to 18 : Same as Series A

Series C

1. When light enters a medium where its speed increases. It will bend:

(a) Randomly (b) Towards the normal (c) Away from the normal (d) Along the normal

Ans: (c) Away from the normal

2. Define Regular reflection?

Ans: Regular reflection is a type of reflection which occurs on plane polished surfaces.

3. What is the focal length of a convex mirror whose radius of curvature is 32 cm?

Ans: The focal length is 16 cm.

4. List two factors on which resistance of a conductor depends.

Ans: The resistance of the conductor depends on the length and the area of cross section of the wire.

5. Draw the symbols of following components used in electric circuit. (a) Electric Bulb (b) Battery

6. What happens when dilute hydrochloric acid is added to iron fillings? Choose the correct answer.

(a) Hydrogen gas and iron chloride are produced (b) Chlorine gas and iron hydroxide are produced

Ans: (a) Hydrogen gas and iron chloride are produced

17. The ore of lead is called

(a) Cinnabar (b) Argentite (c) Galena (d) None of these

Ans: (c) Galena

8. An element having electronic configuration of 2, 8, 2 is

(a) Metal (b) Non Metal (c) Metalloid (d) None of these

Ans: (a) Metal

9. The number of other carbon atoms to which each carbon atom is bonded in diamond is -

(a) 2 (b) 3 (c) 4 (d) 6

Ans: (c) 4

10. The soap molecule has a

(a) Hydrophilic head and Hydrophobic tail (b) Hydrophobic head and a Hydrophilic tail

Ans: (b) Hydrophobic head and a Hydrophilic tail

11. Name the radiations that are absorbed by Ozone blanket.

Ans: The ozone blanket absorbs Ultra Voilet radiations.

12. Name two basic components of Ecosystem.

Ans: The two basic components of ecosystem are Biotic and Abiotic components.

13. What is the basic unit of Heredity?

(a) Nucleus (b) Gene (c) Cell (d) None of these

Ans: (b) Gene

14. What does DNA stand for

(a) Deoxyribonucleic Acid (b) Discontinuous Nucleic Acid (c) Double Nuclear Acid (d) None of these

Ans: (a) Deoxyribonucleic Acid

15. Who is known as father of Genetics -

(a) Charles Darwin (b) Gregor Mendel (c) James Watson (d) None of these

Ans: (b) Gregor Mendel

Notes From Q No's 16 to 18: Same as Series A

SECTION-B

19. On passing through a glass prism white light splits into its seven constituent colors. What is this phenomenon called and how it is caused?

Ans: Dispersion means the split of white light into seven colours.
When the rays of light enter Prism, it splits into spectrum of seven colours called VIBGYOR i.e, Violet, Indigo, Blue, Green, Yellow, Orange, Red.
The light splits because different colours bend at different angles inside prism.
The red light bends least and Violet bends most.

20. What precautions should be taken to avoid the overloading of domestic electric circuits?

Ans: Following precautions should be taken to avoid the overloading of domestic electric circuits:
1. Wires of appropriate power rating and good insulation should be used.
2. There should be separate circuit for heating appliances.
3. Fuse or MCB should be installed.

21. Why does a compass needle get deflected when brought near a bar magnet?

Ans: The compass needle is a small magnet with one end acting as North pole and other as South pole.
When it is bought near a bar magnet, the needle gets deflected due to attraction or replusion.

22. Identify the substance oxidized and the substance reduced in the following reactions

(i) 4Na(s) + O2(g) → 2Na₂O(s) (ii) CuO(s) + H₂(g) → Cu(s) + H₂O(1)

Ans: (I): Sodium is getting oxidized.

(ii) Copper is getting reduced where as Hydrogen is getting oxidized.

23. Why is sodium kept immersed in kerosene oil?

Ans: Sodium is kept immersed in kerosene oil because sodium reacts with both air and water.
Na + O2 _____> Na2O
Na2O + H2O _____> NaOH

24. Why does an aqueous solution of an acid conduct electricity?

Ans: An aqueous solution of acid contains H+ and other anions . Hence it conducts electricity.

25. Which part of the brain maintains posture and equilibrium of the body?

Ans: The Cerebellum maintains posture and equilibrium of the body.

26. What is the importance of DNA copying in reproduction?

Ans: DNA copying mantains body design and perfection in different generations of a species.
Error in DNA copying can lead to abnormalities in the population.

27. Draw a labelled diagram of the longitudinal section of a flower?

Ans:

28. What are the functions performed by the testis in human beings?

Ans: The testes produce sperms and male sex hormone called testosterone.

Series B

19. Question repeated as Q.no 19 of Series A

20. List the properties of magnetic field lines

Ans: Properties of Magnetic Field Lines are:
(i) Magnetic lines of force start from the north pole and travel to the south pole outside the magnet.
(ii) They travel from South to North inside the magnet
(iii) They never intersect each other
(iv) Their magnitude decreases as we move away from the magnet.

21. Question repeated as Q.no 21 of Series A

22. Question repeated as Q.no 22 of Series A

23. Differentiate between Calcination and Roasting.

Ans: Calcination means heating of an ore in absence of oxygen where as Roasting means heating of ore in presence of oxygen.

24. Question repeated as Q.no 24 of Series A

25. Question repeated as Q.no 25 of Series A

26. Question repeated as Q.no 26 of Series A

27. How does binary fission differ from multiple fission?

Ans:

28. Question repeated as Q.no 28 of Series A

Series C

19. Question repeated as Q.no 19 of Series A

20. Draw magnetic field lines around a bar magnet.

Ans:

21. Question repeated as Q.no 21 of Series A

22. Question repeated as Q.no 22 of Series A

23. Give reasons: Platinum, gold and silver are used to make Jewellery.

Ans: Platinum, Gold, Silver are used to make jewellery because they have lustre and do not undergo corrosion.

24. Question repeated as Q.no 24 of Series A

25. Question repeated as Q.no 25 of Series A

26. Question repeated as Q.no 26 of Series A

27. How does the embryo get nourishment inside the mother's body?

Ans: The embryo gets its nourishment through the Placenta.

28. Question repeated as Q.no 28 of Series A

SECTION-C

29. An electric motor takes 5A current from a 220 volt line, determine the power and energy consumed in 2 hours.

Ans: Given, I = 5A, V = 220 V, T = 2 Hrs i.e. 7200 s P= ?, E = ?

We Know that,

P = V x I,

P = 5 x 220

P = 1100 W.

Now, Energy Consumed = P x T

E = 1100 x 7200

E = 7920000 J

OR. An electric iron of resistance 20 Ohm takes a current of 5A. Calculate the heat developed in 30 seconds.

Ans: Given, R= 20 Ω I = 5A T = 30 S

We know,

H = I × I × R x t
H = 5 × 5 × 20 x 30
H = 15, 000 J
The amount of heat developed by the electric iron in 30 s is 15,000 Joules

30. Why do Stars Twinkle?

Ans: The stars twinkle because of atmospheric refraction. As the light of stars enter earth's atmosphere, It bends due to increase in density of air.
When light is refracted towards us, stars appear brighter. When light refracted away from us, the stars appear dim.

OR. Why does the sky appear dark instead of blue to an astronaut?

Ans: The sky appears blue due to the scattering of white light by dust particles, gases and water vapours present in the atmosphere.

The sky appears dark to astronaut since there is no atmosphere present in the space to scatter the rays of light.

30.B Draw the three ray diagrams for the correction of Myopic eye.

Ans:

OR. (i) What is the far point and near point of the human eye with normal vision?

Ans: Far point is maximum distance up to which an eye can see. It is infinite for normal eye.
Near Point is minimum distance up to which an eye can see. It is 25 cm for normal eye

(ii) What is meant by power of accommodation of the eye?

Ans: Power of accommodation means ability of eye to adjust its focal length to see objects at different distances.
It is possible due to change in thickness of eye lens.
To see distant objects, the lens becomes thin. To see near objects, the lens becomes thick

30C: Draw a labelled diagram of human eye.

Ans:

OR. Why does the sun appears reddish early in the morning?

Ans: During sunrise and sunset, the light has to travel greater distance. Most of the blue light is scattered away but red light scatters the least and reaches to us. Thus sky appears Reddish.

31. The magnetic field in a given region is uniform. Draw a diagram to represent it.

Ans: When the magnetic field in a given region is uniform, it is called uniform magnetic magnetic field.
The magnetic lines are equidistant and Parallel.

OR. How does a solenoid behave like a magnet? Can you determine the north and south poles of a current carrying solenoid with the help of a bar magnet? Explain.

Ans: A solenoid is a coil with number of turns of insulated copper wire wound in the form of cylinder.
When current flows through a solenoid it behaves like a magnet with magnetic field lines similar to a bar magnet.

One end of solenoid behaves as north pole and other end behaves as south pole.
When the north end of a bar magnet is bought near one end of solenoid and gets attracts, that that is South pole of Solenoid. If it gets repelled that that is North pole of bar magnet.

32. Balance the following Chemical equations:

(a) HNO3 + Ca(OH)2 → Ca(NO3)2 + H₂O

Ans: 2 HNO3 + Ca(OH)2 → Ca(NO3)2 + H₂O

b) NaOH + H2SO4 -> Na2SO4 + H2O

Ans: 2 NaOH + H2SO4 -> Na2SO4 + 2 H2O

(c) BaCl₂ + H₂SO₄ → BaSO4 + HCl

Ans: BaCl₂ + H₂SO₄ → BaSO4 + 2 HCl

OR. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.

Ans: The reaction in which a compound splits up into two or more simple substances is called decomposition reaction.
Heat: CaCO3 -> CaO + CO2
Light: AgCl -> Ag + Cl2
Electricity: H2O -> H2 + O2

33. Why does distilled water not conduct electricity where as rain water does?

Ans: Rain water contains impurities in form of ions and salts due to which it conducts electricity. However distilled water does not contain ions.

OR. Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd?

Ans: As the curd is more acidic than milk due to presence of lactic acid. Hence, pH will be less than milk.

34. Why do ionic compounds have high melting points?

Ans: Ionic compounds are formed by the attraction of positive and negative ions.

It takes lot of energy to break these bonds. Therefore, they have high melting and boiling points

Or. Define the following terms (a) Mineral (b) Ore (c) Gangue

Ans: a. Mineral: The compounds of elements along with impurities occuring in earths crust are called minerals.
b. Ore: An Ore is mineral from which the element is extracted.
c. Gangue: The impurities present in the ore is called gangue.

35. What are the differences between Autotrophic and Heterotrophic Nutrition?

Ans:

Autotrophic Nutrition	Heterotrophic Nutrition
In this type of Nutrition, organisms prepare their own food	In this type of nutrition, Organisms depend on others for food
It is of two types: Photoautotrophic and Chemoautotrophic	It is of many types: Holozoic, Saprotrophic, Parasitic
It includes green plants, blue green algae, euglena, some bacteria	It includes animals, non-green plants, fungi, some bacteria

OR. Define Haemoglobin. Explain its importance in transporting oxygen and carbon dioxide in the blood.

Ans: Haemoglobin is found inside the RBC’s in the blood and carries oxygen to the body parts and brings back carbon dioxide. Deficiency of haemoglobin causes anaemia.
It leads to tiredness and weight loss.

36. How do auxins promote the growth of a tendril around a support?

Ans: The auxins are growth promoters. They stimulates faster growth of the cells on the opposite side and help the tendril to form a coil around the support.

Or. What is the need for a system of control and coordination in an organism?

Ans: The system of control and co-ordination helps manage all life processes and ensure response to the stimuli in the living organisms.

37. What are Trophic Levels? Give an example of food chain and state the different trophic levels in it?

Ans: The distinct sequential steps in food chain where transfer of energy takes place.
E.g In a food chain,
Plant ----> Sheep -----> Man
Plant belongs to first trophic level. Goat belongs to second trophic level and Man belongs to third trophic level.

OR. What is the role of Decomposers in the Ecosystem?

Ans: Decomposers such as bacteria and fungi feed upon dead matter and convert it back into simple substances, which are then released into ecosystem.
Decomposers help in recycling of nutrients.
Without decomposers, an ecosystem will not sustain.

SECTION-D

38 Define Refraction. With the help of a ray diagram explain refraction of light through a glass slab.

Ans: When light enters from one medium to another, It bends towards the normal or away from it. This process is called refraction.

Laws of Refraction:
1. The Incident Ray, Refracted Ray and z normal are all in same plane.
2. The ratio of Sin of angle of incidence to Sin of angle of refraction is always constant. This is also called snells law.

Or. An object 5.0 cm in length is placed at a distance of 20 cm from the convex mirror of radius of curvature 30 cm. Find the position of the image, its nature and size.

Ans: Given, H = 5 U = - 20 F = + 15 (i.e Half of Radius of Curvature) V =? H’ =?

We Know;

1/F = 1/V + 1/U

1/15 = 1/V + 1/ -20

1/V = 1/15 + 1/20

1/V = 4 + 3/ 60

1/V = 7/60

V= 60/7

V = 8.5 cm

Now, Magnification (m) = H’/H = - V/U

H’/5 = - 8.5/-20

H’ = 8.5 x 5/20

H’ = 2.14 cm

+ve sign indicates that the image is erect and thus inverted.

39. Draw the structures of the following compounds

i. 1-Butene ii. 2-Iodopropane iii. 2-Propanol iv. Butanoic Acid v. 3-Pentanone

Ans:

OR. Discuss briefly the physical and chemical properties of Ethanol.

Ans: Ethanol is commonly called as Alcohol. Ethanol is liquid at room temperature. It is a good solvent.
Its melting point is - 117 °C and boiling point is 77 °C. Its formula is C2H5OH.
Chemical Properties:
1. Reaction with Sodium:
Ethanol reacts with Sodium to form Sodium ethoxide.
C2H5OH + Na ______> C2H5O-Na + H2
2. Reaction with sulphuric acid:
Ethanol is heated with Concentrated Sulphuric acid to form Ethene.
C2H5OH + H2SO4 ______> CH2 = CH2 + H2O
Sulphuric acid acts as dehydrating agent.

40. Describe transport of water and food in plants.

Ans: Water: Water and minerals are transported in plants through xylem.
The process is called ascent of sap.
The sap is absorbed by root hairs by osmosis. It is then transported into cortex cells and xylem.
The sap then moves up the plant by transpiration pull, cohesion and adhesion.

Food: The food is made in leaves of plants by the process of photosynthesis.
The food is then transported to other parts of plant through phloem and the process is called translocation

OR (i) What is the role of saliva in the digestion of food?

Ans: Saliva makes food moist which helps us to taste food and easy to swallow
It contains salivary amylase which convert starch to maltose.
It contains maltase, which convert maltose to glucose

(ii) How are fats digested in our body?

Ans: Fats are mainly digested in duodenum. In duodenum, the food gets mixed with bile from liver and pancreatic juices from pancreas.
Bile helps to emulsify fats that break down large fat molecules into smaller droplets. This process is called Emulsification.
Pancreatic juices contain lipase which breaks down fats into fatty acids