TN Board Class 10 Science Solved Previous Year Question Papers 2019

A student should make it a habit to solve previous year question papers regularly so that they prepare for their exams in a better way. With the help of these previous year papers, students can analyse the strength and weaknesses of the subject. After analysing, they should work on those points and improve them. Thus, TN Board Class 10 Science Solved Previous Year Question Papers 2019 is indeed the best resource for the students to prepare most efficiently for the board exams. Students can first solve the question paper themselves and then refer to the TN Board Class 10 Science Solved Previous Year Question Papers 2019 to self gauge their performance and preparation level.

In this article, we have provided PDF of Tamil Nadu Board Class 10 Science solved previous year question papers. The solutions provided for the question paper of Class 10 Science are solved by subject matter experts and each question is explained elaborately with proper diagrams and required examples.

TN Board Class 10 Science Solved Question Paper 2019

1. Which of the following is inheritable?

• an altered gene in sperm,
• an altered gene in liver cells,
• an altered gene in skin cells,
• an altered gene in udder cells.

Answer: An altered gene in sperm

2. Which one of the following is not a hereditary disease?

• Thalassemia
• Down’s syndrome
• Alzheimer’s disease
• Haemophilia

Answer: Alzheimer’s disease

3. Spinal nerves are ___

• Sensory nerves
• Motor nerves
• Mixed nerves
• Innervating the brain

Answer: Mixed nerves

4. During post fertilization, the ovule changes into a/an ___

• Seed
• Fruit
• Endosperm
• Peicarp

Answer: Seed

5. Carnivorous animals use ____ teeth to tear flesh.

• Incisors
• Canines
• Premolars
• Molars

Answer: Canines

6. ____ of green plants are called ‘factories of food production’.

• Mitochondria
• Chloroplasts,
• Endoplasmic
• Reticulum
• Nucleus

Answer: Chloroplasts

7. Find the odd one out.

• Bio-alcohol
• Green diesel
• Bio-ethers
• Petroleum

Answer: Petroleum

8. Dispersed medium+ Dispersion medium

• True Solution
• Colloidal Solution
• Suspension
• All

Answer: Colloidal Solution

9. When aqueous solution of Silver Nitrate and Sodium chloride are mixed……precipitate is immediately formed.

• White
• Yellow
• Red
• Blue

Answer: White

10. ____ is used in making electromagnets.

• Pig iron
• Steel
• Wrought iron
• Nickel steel

Answer: Nickel Steel

11. ____ is the functional group of ketones.

Answer:

12. One light year is equal to ___

(365.25 × 24 × 60 × 60 × 3 × 10⁸m, 60 × 60 × 3 × 10⁸m, 1 × 24 × 60 × 60 × 3 × 10⁸m, 360 × 24 × 60 × 60 × 3 × 10⁸m)

Answer: 365.25 × 24 × 60 × 60 × 3 × 10⁸m

13. The value of ‘G’ is

(6.673 X 10¹¹ Nm²kg^-2, 6.673 X 10^-11 Nm²kg^-2, 6.673 x 10¹¹Nm^-2kg^-2, 6.673 X 10^-11 Nm²kg²)

Answer: 6.67×10^-11 Nm²/kg²

14. How much work is done in moving a charge of 2 C across two points having a potential difference 10 V?

• 5 J
• 20 J
• 0.2 J
• 2 J

Answer: 20 J

15. A device that reverses the direction of flow of current through a circuit is called

• Voltmeter
• Ammeter
• Commutator
• Transformer

Answer: Commutator

16. Name the sources of somatic stem cells.

Answer: The sources of somatic stem cells are Bone Marrow, Cord Blood

17. (i) I was born when the diploid nucleus of the udder cells injected into the cytoplasm of the enucleated ovum and implanted into the uterus of the surrogate mother.

(ii) I coined the term vaccine and vaccination for protective inoculation.

Answer i: Dolly the first mammal cloned sheep.

Answer ii: Edward Jenner

18. Fill in the blanks:

(i) The first vaccine which is produced by Biotechnology was used against

(ii) Biotechnologically synthesized ____ is used to cure pernicious anemia.

Answer i: Hepatitis B

Answer ii: Vitamin b-12 shots/injections

19. What are the symptoms of Malaria?

Answer: Symptoms of malaria are exhibited within 7 to 18 days of being infected. Common symptoms include:

• Fever, fatigue, chills, vomiting, and headaches
• Diarrhoea, anaemia and muscle pain
• Profuse sweating and convulsions
• Bloody stools.
• In severe cases, malaria can be devastating; it can lead to seizures, coma and eventually, death.

20. What is Corpora quadrigemina? Name the functions associated with it.

Answer: Corpora quadrigemina is a part of the brain that is formed by the grey matter of nerve cells that is scattered in white matter. It is a group of four colliculi that are found at the dorsal aspect of the mid brain just below the thalamus. The Corpora quadrigemina forms the connection between the mid brain and the hind brain.

The functions associated with it are as follows:

• The corpora quadrigemina has four colliculi, two superior and two inferior.
• The superior colliculi of the corpora quadragemina contain the correlation centers for the optic reflexes while the inferior colliculi contain the correlation centers for auditory reflexes
• In simple terms, it associated with hearing and seeing.

21. Draw the given diagram and label the parts.

Answer:

22. Assertion (A): In summer, we sweat more.

Reason (R): The kidneys expel less urine, since much of water is lost in the form of sweat.

(a) Both (A) and (R) are true and (R) explains (A).

(b) Both (A) and (R) are true but (R) doesn’t explain (A).

(c) (A) is true but (R) is false.

(d) (A) is false but (R) is true.

Answer: a

23. Draw the LS of kidney and label the parts.

Answer:

24. Mention any four adaptations seen in the Camel so that it can live successful1y in deserts.

Answer: The four adaptations seen in the Camel so that it can live successfully in deserts are:

• Two rows of long eye-lashes
• Fat stored in humps
• Thick leathery patches on knees.
• Thick fur and underwool

25. Why diffusion process is not suitable for transportation in multicellular organisms?

Answer: Unicellular organisms have specialised cells and tissues for performing various necessary functions of the body such as intake of food and oxygen. Unlike unicellular organisms, multicellular cells are not in direct contact with the outside environment. Therefore, diffusion cannot meet their oxygen requirements.

26. What are Saprophytes? Give two examples.

Answer: Saprophytes are the living organisms that live and feed on dead and decaying organisms. They are considered extremely important in soil biology. They break down the complex organic matter into simpler substances that is taken up by the plants for various metabolic activities. Thus, saprophytes play a significant role in the ecosystem. Eg: Yeast and Cheese mold.

Saprophytes have certain characteristic features:

• They produce filaments.
• They are devoid of leaves, roots and stem.
• They cannot perform photosynthesis and are heterotrophs.
• They can produce spores.

The saprophytes secrete digestive juices and breakdown the organic matter around them. The fungi grow tubular structures known as hyphae that branch into the dead matter and produce digestive enzymes.

27: Match the methods of nutrition of special organs with suitable examples.

Answer:

28. Study the food chain below, correct it and convert it into a pyramid of energy.

Mulberry ➔ Sparrow ➔ Caterpillar ➔ Kite.

Answer: Mulberry → Caterpillar → Sparrow → Kite

• First, Mulberry because it is a plant which is autotrophic.
• Second, caterpillar that feeds on mulberry which is a primary consumer
• Third, sparrow which is a bird feeds on the caterpillar and it is a secondary consumer.
• Fourth, the kite which eats the sparrow and acts as the tertiary consumer.

29. Why hydrogen is considered to be the best choice among all the alternative fuel options?

Answer: Hydrogen is considered to be the best choice among all the alternative fuel options because it is non-toxic, and reasonably safe to handle and distribute. It has the highest mass energy content.

30. A non-renewable resource is a natural resource. It can be replaced by natural process at a rate equal to or faster than its rate of consumption by humans.

Read this statement and say whether it is correct or incorrect. If it is incorrect, give the correct statement.

Answer: This statement is incorrect because a renewable resource is a natural resource. It can be replaced by natural process at a rate equal to or faster than its rate of consumption by humans.

31. How will you reuse the waste water in your houses?

Answer: We can reuse the waste water in our houses by following ways:

• By watering yards and gardens
• Filtering septic systems.
• By irrigating fields.

32. What is called Brownian movement?

Answer: The random zig-zag motion of a particle observed under high power ultra-microscope is known as Brownian Movement. This motion resembles the exact motion of pollen grains in water as explained by Robert Brown, hence, the name Brownian movement.

More significantly, Albert Einstein’s later explained the Brownian motion more clearly in his paper stating that the pollen was moved by water molecules. This discovery served as great evidence of the existence of atoms and molecules.

Understanding Brownian movement is crucial as it forms a base for the modern atomic theory. The kinetic theory of gases is also based on the Brownian motion model of particles. Additionally, the mathematical models describing Brownian motion are used in a variety of disciplines such as Maths, Physics, Chemistry, Economics, etc.

33. Fill in the blanks

Solute, Solvent, Example

Solid,…….., Smoke

………, Solid, Cork

Answer:

Solute, Solvent, Example

Solid, Gas, Smoke

Gas, Solid, Cork

34. Identify and correct the mistake if any:

1. 2 × R.M.M = V.D
2. The molar volume of gas at STP is 22.4 cm³

Answer: Errors: The molar volume of gas at STP is 22.4 litres

35. The hydroxide ion concentration of a solution is l.0 x 10^-8 M. What is the pH of the solution?

Answer: Solution: pOH = -log¹⁰ [OH^–]

pOH = -log¹⁰ (1.0 × 10⁸)

pOH = 8

pH = 14 – pOH

pH = 14 – 8

pH = 8

So, the pH value of the solution is 8.

36. Which of the following reactions does not take place? State the reason.

1. FeS0₄ +Mg➔ MgS0₄ +Fe
2. ZnSO₄ + Cu ➔ CuSO₄ + Zn

Answer: Among the two the second reaction does not take place because Zinc is more reactive than copper.

37. To design the body of an aircraft, aluminum alloys are used. Give reasons.

Answer: While designing the body of an aircraft, aluminum alloys are used because the alloys are light weighed, have high tensile strength and corrosion resistant.

38. Draw the given diagram and label the parts.

Answer:

39. Assertion: Chemical bonds in organic compounds are covalent in nature.

Reason: Covalent bond is formed by the sharing of electrons in the bonding atoms

Does the reason satisfy the assertion?

Answer: Yes, the reason satisfies the assertion.

40. List out the names of the organisations which are not associated with Chandrayaan -I mission from the following:

(ISRO, BARC, NASA, ESA, WHO, ONGC)

Answer: The organisations which are not associated with Chandrayaan – I are BARC, WHO, ONGC.

41. Two similar trucks are moving with the same velocity on a road. One of them is loaded while the other is empty. Which of the two will require a large force to stop it.

Answer: Among the two trucks the loaded truck will require a large force to stop it because loaded truck has more inertia or greater momentum than the empty truck.

42. An electric bulb is connected to a 240 V generator. The current is 0.65 A. What is the power of the bulb?

Answer: V = 240 V, I = 0.65 A

The power of the bulb, P = VI

= 240 x 0.65

= 156 W

The power of the bulb is 15 W.

43. What are the limitations in harnessing wind energy?

Answer: Limitations in obtaining energy from wind.

• There will not be continuous and consistent production
• Area required to install wind power mill is large.
• Minimum speed of the wind should be 15 km/hour.

44. Find the effective resistance between A and B in the given circuit.

Answer: R_{1 +} R₂ are parallel.

1/R₁₂ = 1/R₁ + 1/R

1/R₁₂ = 1/2 + 1/1

1/R/12 = 3/2

R₁₂/1 = 2/3Ω

R/12 = 2/3 Ω

R₃, R₄ are parallel

1/R₃₄ = 1/R₃ + 1/R₄

1/R₃₄ = 1/2 + 1/1

1/R₃₄ = 3/2

R₃₄/1 = 2/3 Ω

R₃₄ = 2/3 Ω

R₁₂, R₅, R₃₄ series

R_S = R₁₂ + R₅ + R₃₄

R_S = 2/3 + 2 + 2/3

R_S = 2 + 2 × 3 + 2/3

R_S = 10/3

The effective resistance between A and B in the given circuit R_S = 3.33Ω

45. Define Power of Lens. Give its units.

Answer: The power of a lens is defined as the reciprocal of its focal length, it is 4 represented by the letter ‘p’.

p = 1/f

The SI unit of power of lens is ‘dioptre’ by the letter ‘D’.

46. How can an AC generator be converted into a DC generator?

Answer: An AC generator can be converted into a DC generator by changing slip rings into split ring type commutator. Commutator is an attachment, connected with the armature of a motor or dynamo, through which electrical connection is made and which ensures the current flows as direct current.

47. Assertion (A): When white light is allowed to pass through a prism, it splits into seven colours.

Reason (R): This is due to reflection of light.

(a) Both (A) and (R) are correct and (R) explains (A).

(b) Both (A) and (R) are correct but (R) does not explain (A).

(c) (A) is wrong (R) is correct.

(d) Both (A) and (R) arc wrong.

Answer: b

48. Explain elaborately about Typhoid fever.

Answer: Typhoid: Typhoid is an infectious bacterial disease that mainly spreads through contaminated food or water. It can also spread due to poor hygienic conditions. The major symptoms of this disease are characterized by high fever, loss of appetite and diarrhoea. Salmonella typhi is the bacterium responsible for this disease and humans are the only carriers.

Causes of Typhoid

“Salmonella enterica serotype Typhi”, this microbe is the causative agent for this disease. It is a gram-negative bacteria characterized by a thin cell wall and an outer membrane. The cells are reddish in colour, with some having black stains in the centre.

The bacteria enter the human body through the contaminated foods and water, where it then enters into the intestinal cells of the human body. Later, it passes through the bloodstream and destroys the lymphatic system and spreads throughout the body. This bacterium is mainly carried by the white blood cells present in the liver and also the bone marrow. There, they multiply and re-enter the blood cells, which in turn, causes a number of symptoms to appear in the later stages.

Symptoms of Typhoid

Patients affected with typhoid usually display the following symptoms:

• Malaise or weakness.
• Loss of Appetite
• Abdominal Pain.
• Ulcers
• Constipation
• Hallucinations
• High Fever
• Dehydration
• Skin rashes

Treatment for Typhoid

Sanitation is one of the most important things that one can do to prevent the infection of such diseases. The other way would be the use of antibiotics that can kill the disease-causing germs. Also by maintaining good and hygienic food habits, one can get rid of diseases easily.

49. Explain the Peripheral Nervous System.

Answer: Peripheral nervous system involves the parts of the nervous system outside the brain and the spinal cord. The peripheral nervous system is divided into two parts:

• Somatic Nervous System
• Autonomic Nervous System

Peripheral Nervous System Parts

Following are the major parts of the peripheral nervous system:

• Somatic Nervous System

The main function of the somatic nervous system is to transfer impulses from CNS to skeletal muscles. It consists of

• Cranial Nerves
• Spinal Nerves

Cranial nerves emerge from the brain and there are twelve pairs of cranial nerves. Some of the examples may be the sensory nerves like optic, olfactory, etc.

Spinal nerves have their point of emergence as the spinal cords. There are thirty-one pairs of spinal nerves. They emerge from the spinal cords into dorsal and ventral roots. At the junction of these two roots, the sensory fibers continue into the dorsal root and the motor fibers into the ventral root.

Autonomic Nervous System

The autonomic nervous system relays impulses from the central nervous system to the involuntary organs and smooth muscles of the body.

It is further divided into two parts –

• Sympathetic Nervous System
• Parasympathetic Nervous System

The sympathetic nervous system consists of nerves arising from spinal cord between the neck and waist region. It prepares the body for violent actions against abnormal conditions and is generally stimulated by adrenaline.

The parasympathetic nervous system is located anterior in the head and neck and posterior in the sacral region. It is mainly involved in re-establishment of normal conditions when violent action is over.

50. Describe the structure of a dicot seed.

Answer:

• The seed is bulky, oval and slightly indented on one side. On this side, there is a short longitudinal, whitish ridge called the raphae.
• At one end of the raphae, there is a minute opening known as germ pore or micropyle.
• The embryo is enclosed by the seed coat. It consists of cotyledons attached to the primary axis.
• Rudimentary root portion called the radicle and a rudimentary stem portion known as plumule.
• The tip of the radicle projects outside, and is nearer to the micropyle.
• The plumule is placed between the two cotyledons and consists of a shoot axis and a small bud having two tiny folded leaves.

51. Explain the components of Pond eco-system.

Answer:

1. Pond Ecosystem: Pond can be considered as an example for aquatic ecosystem.

Abiotic factors:

• Inorganic substances like CO_2, H₂, O₂, N, PO₄, CO₃ and S
• Organic substances like carbohydrates, proteins and lipids.

2. Biotic factors:

They include producers and consumers. Producers are the water living plants like Hydrilla, Vallisneria etc. and phytoplankton like Chlamydomonas, Volvox and Spirogyra.

3. Primary consumers or herbivores:

Zooplanktons like insects, larvae of dragon-fly consume the phytoplanktons.

4. Secondary Consumers:

These are certain fishes, frogs, water beetles etc. which feed on the primary consumers in the pond.

5. Tertiary Consumers:

These are big fishes and birds that feed on small fishes.

6. Decomposers:

Several bacteria and fungi form the decomposers in the pond.

52. Nitroglycerine is used as an explosive. -The-equation for _the explosive reaction is:

4C₃H₅(NO₃)₃ ➔ 12CO₂ + 10H₂0 + 6N₂ + O₂

(l) (g) (l) (g) (g)

(Atomic mass of C = 12, H = 1, N = 14, O = 16)

(a) How many moles does the equation show for?

(i) Nitroglycerine

(ii) Gas molecules produced?

(b) How many moles of gas molecules are obtained from 1 mole of nitroglycerine?

(c) What is the mass of 1 mole of nitroglycerine?

Answer: (a) i 4 moles of Nitroglycerine

(ii) 19 moles of gas molecule

b): 4 moles of nitroglycerine gives 19 moles of gas molecules

1 mole of nitroglycerine gives = 19/4 = 4.75 moles of gas molecules

c): Nitroglycerine C₃H₅(NO₃)₃ = (3 x 12) + (5 x1) + (3x 14) + (3 x16)

= 36+ 5 +42+144 = 227g

Mass = No. of moles x molecular mass

= 1 x 227

= 227g

53. (a) What are alkynes? Give an example.

(b) If the molecular mass of an alkynes is 54, then its molecular formula is…….

Answer: (a) Alkanes are organic compounds that consist of single-bonded carbon and hydrogen atoms. The formula for Alkanes is C_nH2_n+2, subdivided into three groups – chain alkanes, cycloalkanes, and the branched alkanes. Example: Ethane ((C₂H₆)

b) Molecular Formula:

H₃C – C ≡ C – CH₃(2-Butyne)

H₃C – CH₂ – C ≡ CH(1-Butyne)

54. (a) A and B are two objects. What happens to the force between two objects, if:

1. the mass of A is doubled.
2. the distance between A and B is doubled.
3. the mass of both A and B are doubled.

(b) What is the relation between ‘g’ and ‘G’?

Answer: a (i) the mass of A is doubled

𝐹′ = Gm₁m₂/d²

𝐹′ = 𝐺2𝑚_𝐴𝑚_𝐵/d²

𝐹′ = 2 (𝐺𝑚_𝐴𝑚_𝐵/d²)

𝐹′ = 2F

Force is doubled.

(ii) the distance between A and B is doubled.

𝐹′ = Gm_Am_B/2d²

𝐹′ = 𝐺2𝑚_𝐴𝑚_𝐵/4d²

𝐹′ = 1/4 (𝐺𝑚_𝐴𝑚_𝐵/d²)

𝐹′ = F/4

Force is decreased by 4 times.

(iii) the mass of both A and B are doubled.

𝐹′ = 𝐺2𝑚_𝐴2𝑚_𝐵/2d²

𝐹′ = 4 (𝐺𝑚_𝐴𝑚_𝐵/d²)

𝐹′ = 4F

Force is increased four times.

(b) The relation between ‘g’ and ‘G’

g = GM/R²

(i) g = acceleration due to gravity

(ii) Its unit is m/s²

(iii) g is independent of mass of the body (g=9.8ms^-2)

(i) G = gravitational constant

(ii) Its unit is Nm²Kg^-2

(iii) G = 6.673×10^-11 Nm2Kg^-2

55. (a) Write the sign convention for reflection by spherical mirrors.

(b) Why convex mirrors are used as rear-view mirrors in vehicles?

Answer:

(a) Sign convention for reflection by spherical mirrors:

• The object is always placed to the left of the mirror.
• All distances parallel to the principal axis are measured from the pole of the mirror.
• All the distances measured to the right of the origin (along +X axis) are taken as positive while those measured to the left of the origin (along -X axis) are taken as negative
• Distances measured perpendicular to and above the principal axis (along +Y axis) are taken as positive.
• Distances measured perpendicular to and below the principal axis (along -Y axis) are taken as negative.

(b) We prefer a convex mirror as a rear-view mirror in vehicles because it gives a wider field of view, which allows the driver to see most of the traffic behind him. Convex mirrors always form a virtual, erect, and diminished image of the objects placed in front of it.