10th Science Quarterly Exam 2024
Question Paper & Solutions
(Ariyalur District)
PART - I
ii) Choose the most suitable answer and write the code with the corresponding answer.
1. To project the rockets which of the following principle(s) is/are required?
2. Where should an object be placed so that a real and inverted image of same size is obtained by a convex lens.
3. A charge of 12 coulomb flows through a bulb in 5 second. What is the current through the bulb?
4. Which of the following has the smallest mass?
5. .......... is an important metal to form amalgam
6. A 25% alcohol solution means
7. The animals which give birth to young ones are
8. Which is the sequence of correct blood flow
9. Vomiting centre is located in
10. Which one is referred as "Master Gland"?
11. Syngamy results in the formation of ..........
12. 9:3:3:1 ratio is due to
PART - II
13. Define inertia. Give its classification.
Answer:
Inertia: The inherent property of a body to resist any change in its state of rest or the state of uniform motion, unless it is influenced by an external unbalanced force, is known as inertia.
Classification:
- Inertia of rest: The resistance of a body to change its state of rest. (e.g., A person standing in a bus leans backward when the bus starts suddenly).
- Inertia of motion: The resistance of a body to change its state of uniform motion. (e.g., An athlete runs some distance before jumping to gain inertia of motion).
- Inertia of direction: The resistance of a body to change its direction of motion. (e.g., When a car makes a sharp turn, you tend to lean sideways).
14. Distinguish between ideal and real gas.
Answer:
| Ideal Gas | Real Gas |
|---|---|
| The volume occupied by the molecules is negligible compared to the volume of the gas. | The volume occupied by the molecules is not negligible compared to the volume of the gas. |
| There is no force of attraction or repulsion between the molecules. | There is a force of attraction or repulsion between the molecules. |
| Obeys gas laws (Boyle's Law, Charles' Law) under all conditions of temperature and pressure. | Obeys gas laws only at high temperature and low pressure. |
15. Match the following:
- Galvanisation - Silver - tin amalgam
- Calcination - Alumino thermic process
- Redox reaction - Heating in the absence of air
- Dental filling - Coating with Zn
Answer:
- Galvanisation - Coating with Zn
- Calcination - Heating in the absence of air
- Redox reaction - Alumino thermic process
- Dental filling - Silver - tin amalgam
16. Define Atomicity. Give any two examples for hetero diatomic molecules.
Answer:
Atomicity: The number of atoms present in one molecule of an element is called the atomicity of that element.
Hetero diatomic molecules: Molecules made of two different atoms.
Examples:
- Hydrogen Chloride (HCl)
- Carbon Monoxide (CO)
17. The aquatic animals live more in cold region. Why?
Answer:
The solubility of gases in liquids decreases with an increase in temperature. In cold regions, the water temperature is low. Therefore, more oxygen is dissolved in the water of cold regions compared to warm regions. As aquatic animals need dissolved oxygen for breathing, they feel more comfortable and live more in cold regions.
18. What is respiratory quotient?
Answer:
Respiratory Quotient (RQ) is the ratio of the volume of carbon dioxide evolved to the volume of oxygen consumed during respiration.
RQ = Volume of CO₂ evolved / Volume of O₂ consumed
19. Write the dental formula of rabbit.
Answer:
The dental formula of a rabbit is I 2/1, C 0/0, PM 3/2, M 3/3. This can be written as:
(2033 / 1023)
20. Identify the parts A, B, C and D in the given figure.
Answer:
- A: Capsule
- B: Cortex
- C: Blood vessels
- D: Medulla
21. What are Okazaki fragments?
Answer:
During DNA replication, the lagging strand is synthesized discontinuously in short segments. These short, newly synthesized DNA fragments that are formed on the lagging template strand are called Okazaki fragments. They are later joined together by the enzyme DNA ligase to form a continuous strand.
22. (Compulsory) The work done in moving a charge of 10 C across two points in a circuit is 100 J. What is the potential difference between the points?
Answer:
Given:
- Charge (Q) = 10 C
- Work done (W) = 100 J
Formula for Potential Difference (V):
V = W / Q
Calculation:
V = 100 J / 10 C
V = 10 Volts
The potential difference between the points is 10 V.
PART - III
23. State and prove the law of conservation of linear momentum.
Answer:
Statement: In the absence of an external unbalanced force, the algebraic sum of the momentum of a system of bodies remains constant.
Proof:
Let two bodies A and B of masses m₁ and m₂ move with initial velocity u₁ and u₂ in a straight line (u₁ > u₂). They collide for a short time 't' and separate with final velocities v₁ and v₂.
During collision, the force exerted by body A on B (FB) is:
FB = m₂(v₂ - u₂)/t
The force exerted by body B on A (FA) is:
FA = m₁(v₁ - u₁)/t
By Newton's third law of motion, the force exerted by A on B is equal and opposite to the force exerted by B on A.
FA = -FB
m₁(v₁ - u₁)/t = -[m₂(v₂ - u₂)/t]
m₁v₁ - m₁u₁ = -m₂v₂ + m₂u₂
m₁v₁ + m₂v₂ = m₁u₁ + m₂u₂
This shows that the total momentum after collision is equal to the total momentum before collision, provided no external force acts on the system. Hence, the law is proved.
24. Differentiate convex lens and concave lens.
Answer:
| Feature | Convex Lens | Concave Lens |
|---|---|---|
| Shape | Thicker at the center, thinner at the edges. | Thinner at the center, thicker at the edges. |
| Action on Light | Converging lens. It converges a parallel beam of light. | Diverging lens. It diverges a parallel beam of light. |
| Focal Point | Has a real focus. | Has a virtual focus. |
| Image Formed | Forms real and inverted images (mostly), and one case of virtual and erect image. | Forms virtual, erect, and diminished images. |
25. Derive the ideal gas equation
Answer:
The ideal gas equation is derived by combining the three gas laws: Boyle's Law, Charles' Law, and Avogadro's Law.
1. Boyle's Law: At constant temperature (T) and number of moles (n), the volume (V) of a gas is inversely proportional to its pressure (P).
V ∝ 1/P (at constant T and n) ... (1)
2. Charles' Law: At constant pressure (P) and number of moles (n), the volume (V) of a gas is directly proportional to its absolute temperature (T).
V ∝ T (at constant P and n) ... (2)
3. Avogadro's Law: At constant temperature (T) and pressure (P), the volume (V) of a gas is directly proportional to the number of moles (n).
V ∝ n (at constant T and P) ... (3)
Combining equations (1), (2), and (3), we get:
V ∝ (1/P) × T × n
V ∝ nT/P
V = R (nT/P), where R is the proportionality constant called the Universal Gas Constant.
Rearranging the equation, we get the ideal gas equation:
PV = nRT
26. Give the salient features of "Modern atomic theory"
Answer:
The salient features of Modern Atomic Theory are:
- An atom is no longer indivisible. It is made up of subatomic particles like protons, neutrons, and electrons.
- Atoms of the same element may not be similar in all respects. They can have different atomic masses (Isotopes, e.g., 12C, 13C, 14C).
- Atoms of different elements may have the same atomic mass (Isobars, e.g., 40Ar, 40Ca).
- An atom is the smallest particle that takes part in a chemical reaction.
- The mass of an atom can be converted into energy according to the equation E = mc².
- The ratio in which atoms combine may not be simple whole numbers (e.g., in sucrose C12H22O11, the ratio is 12:22:11).
27. 'A' is a reddish brown metal, which combines with O₂ at < 1370K gives B, a black coloured compound. At a temperature >1370K, A gives C which is red in colour. Find A, B and C with reaction.
Answer:
The reddish-brown metal 'A' is Copper (Cu).
Finding B:
Copper (A) combines with Oxygen (O₂) at a temperature below 1370K to form a black compound, which is Copper(II) oxide (CuO).
Reaction: 2Cu(s) + O₂(g) --(<1370K)--> 2CuO(s)
So, A = Copper (Cu) and B = Copper(II) oxide (CuO) (black).
Finding C:
At a temperature above 1370K, Copper (A) reacts with Oxygen to form a red compound, which is Copper(I) oxide (Cu₂O).
Reaction: 4Cu(s) + O₂(g) --(>1370K)--> 2Cu₂O(s)
So, C = Copper(I) oxide (Cu₂O) (red).
28. Differentiate - Monocot root and Dicot root
Answer:
| Feature | Monocot Root | Dicot Root |
|---|---|---|
| Number of Xylem Bundles | Polyarch (many xylem bundles). | Tetrarch (four xylem bundles). |
| Pith | Large and well-developed at the center. | Small or absent. |
| Secondary Growth | Does not occur. | Occurs, due to the presence of cambium. |
| Cortex | Wide cortex. | Comparatively narrow cortex. |
29. With a neat labeled diagram explain the structure of a neuron.
Answer:
A neuron (nerve cell) is the structural and functional unit of the nervous system. It consists of three main parts:
- Cyton (Cell Body or Soma): It is the main part of the neuron. It has a central nucleus and cytoplasm with characteristic deeply stained particles called Nissl's granules.
- Dendrites: These are short, branched processes that project from the cyton. They receive signals from other neurons and transmit them towards the cell body.
- Axon: This is a single, long, slender projection that arises from the cyton. It conducts nerve impulses away from the cell body to other neurons or to an effector organ (like a muscle or gland). The axon is covered by a protective sheath called the myelin sheath, which is formed by Schwann cells. The myelin sheath is not continuous and has gaps called Nodes of Ranvier. The end of the axon branches into terminal buttons (axon terminals) which contain neurotransmitters.
30. What are the conditions which occur due to lack of ADH and insulin? How are the conditions different from one another.
Answer:
Lack of ADH (Antidiuretic Hormone): Leads to a condition called Diabetes Insipidus.
Lack of Insulin: Leads to a condition called Diabetes Mellitus.
Differences:
| Feature | Diabetes Insipidus (Lack of ADH) | Diabetes Mellitus (Lack of Insulin) |
|---|---|---|
| Cause | Impaired synthesis or release of ADH from the posterior pituitary gland. | Failure of beta-cells of the pancreas to produce sufficient insulin. |
| Primary Effect | Kidneys are unable to reabsorb water, leading to excretion of large volumes of dilute urine (polyuria). | Body cells are unable to utilize glucose from the blood, leading to high blood sugar (hyperglycemia). |
| Urine Characteristics | Urine is dilute and does not contain glucose. | Urine is concentrated and contains glucose (glycosuria). |
| Symptoms | Extreme thirst (polydipsia) and frequent urination of large volumes of water. | High blood sugar, thirst, frequent urination, presence of glucose and ketone bodies in urine. |
31. With a neat labeled diagram describe the parts of a typical angiospermic ovule.
Answer:
A typical angiospermic ovule is a small structure attached to the placenta by a stalk called the funicle.
The main parts are:
- Funicle: The stalk that attaches the ovule to the placenta.
- Hilum: The point of attachment of the funicle to the body of the ovule.
- Nucellus: The main body of the ovule, composed of mass of parenchymatous tissue. It provides nourishment to the developing embryo.
- Integuments: One or two protective layers surrounding the nucellus.
- Micropyle: A small opening at the apex of the integuments through which the pollen tube usually enters.
- Chalaza: The basal part of the ovule, opposite to the micropyle, where the nucellus, integuments, and funicle meet.
- Embryo Sac (Female Gametophyte): A large, oval cell located within the nucellus. It contains the egg cell and other associated cells.
32. (Compulsory)
(i) A solution is prepared by dissolving 45 g of Sodium Chloride in 180 g of water. Calculate the mass percentage of solute.
(ii) 7.5 litres of ethanol is present in 15 litres of aqueous solution of ethanol. Calculate volume percent of ethanol solution.
Answer:
(i) Mass Percentage Calculation
- Mass of solute (Sodium Chloride) = 45 g
- Mass of solvent (water) = 180 g
- Mass of solution = Mass of solute + Mass of solvent = 45 g + 180 g = 225 g
Formula: Mass % of solute = (Mass of solute / Mass of solution) × 100
Calculation: Mass % = (45 / 225) × 100 = (1/5) × 100 = 20 %
The mass percentage of the solute is 20%.
(ii) Volume Percentage Calculation
- Volume of solute (ethanol) = 7.5 litres
- Volume of solution = 15 litres
Formula: Volume % of solute = (Volume of solute / Volume of solution) × 100
Calculation: Volume % = (7.5 / 15) × 100 = (1/2) × 100 = 50 %
The volume percent of the ethanol solution is 50%.
PART - IV
33. (a)
(i) List any four properties of light
(ii) State Newton's second law
(iii) Define - Ampere
Answer:
(i) Four Properties of Light:
- Rectilinear Propagation: Light travels in a straight line in a homogenous medium.
- Reflection: When light falls on a polished surface, it bounces back.
- Refraction: When light travels from one medium to another, it bends.
- Speed: Light travels at a very high speed of 3 × 10⁸ m/s in a vacuum or air.
(ii) Newton's Second Law of Motion:
The force acting on a body is directly proportional to the rate of change of its linear momentum and the change in momentum takes place in the direction of the force. Mathematically, F ∝ (mv-mu)/t or F = kma. In SI units, k=1, so F = ma.
(iii) Define - Ampere:
One Ampere is defined as the current that flows when one coulomb of charge passes through a cross-section of a conductor in one second. (1 A = 1 C / 1 s).
(OR)
33. (b)
(i) List the merits of LED bulb
(ii) State Boyle's law
Answer:
(i) Merits of LED bulb:
- Energy Efficient: It has a very low power consumption, making it highly energy efficient compared to fluorescent and incandescent lamps.
- Long Lifespan: LED bulbs have a longer lifespan, lasting up to 50,000 hours or more.
- Eco-friendly: They do not contain harmful substances like mercury, making them safer for the environment.
- Durable: Being a solid-state lighting device, they are resistant to shock and vibration.
- Compact Size: LEDs are very small and can be used in a variety of applications.
(ii) Boyle's Law:
Boyle's Law states that when the temperature of a gas is kept constant, the volume of a fixed mass of gas is inversely proportional to its pressure. Mathematically, P ∝ 1/V or PV = constant.
34. a)
(i) Calculate the % of each element in calcium carbonate (C-12, O-16, Ca-40)
(ii) The average atomic mass of hydrogen is ..........
(iii) State two conditions necessary for rusting iron.
Answer:
(i) Percentage composition of Calcium Carbonate (CaCO₃):
Molar mass of CaCO₃ = (1 × Atomic mass of Ca) + (1 × Atomic mass of C) + (3 × Atomic mass of O)
= (1 × 40) + (1 × 12) + (3 × 16) = 40 + 12 + 48 = 100 g/mol
- % of Calcium (Ca): (Mass of Ca / Molar mass of CaCO₃) × 100 = (40 / 100) × 100 = 40%
- % of Carbon (C): (Mass of C / Molar mass of CaCO₃) × 100 = (12 / 100) × 100 = 12%
- % of Oxygen (O): (Mass of O / Molar mass of CaCO₃) × 100 = (48 / 100) × 100 = 48%
(ii) The average atomic mass of hydrogen is 1.008 amu.
(iii) Two conditions necessary for rusting iron:
- Presence of air (oxygen).
- Presence of water (moisture).
(OR)
34. b)
(i) In what way hygroscopic substances differ from deliquescent substances.
(ii) Write the uses of Aluminium
Answer:
(i) Difference between Hygroscopic and Deliquescent Substances:
| Feature | Hygroscopic Substances | Deliquescent Substances |
|---|---|---|
| Action | They absorb moisture from the air when exposed to it. | They absorb enough moisture from the air to dissolve completely and form a solution. |
| Physical State | They do not change their physical state. They can be amorphous or crystalline. | They are crystalline solids that become liquid by absorbing moisture. |
| Examples | Concentrated Sulphuric acid (H₂SO₄), Silica gel, Quicklime (CaO). | Caustic soda (NaOH), Potash (KOH), Calcium chloride (CaCl₂). |
(ii) Uses of Aluminium:
- Used in making household utensils.
- Used for making electrical cables due to its good conductivity and low cost.
- Its alloys (like Duralumin, Magnalium) are used to make parts of aeroplanes and other vehicles due to their strength and light weight.
- Used as a wrapping material (aluminium foil) for food and other products.
- Used in paints and lacquers to prevent corrosion.
35. a)
i) Give the importance of transpiration
ii) Define triple fusion.
iii) What are allosomes?
Answer:
i) Importance of Transpiration:
- Transpiration Pull: It creates a suction force that helps in the upward movement of water and minerals from the roots to the leaves (ascent of sap).
- Cooling Effect: It helps in cooling the surface of the leaves and the plant body by evaporation.
- Absorption of Water: It helps in the continuous absorption of water by the roots.
- Maintains Turgidity: It helps to maintain the shape and turgidity of the plant cells.
ii) Define Triple Fusion:
In flowering plants, during double fertilization, one of the male gametes from the pollen tube fuses with the diploid secondary nucleus (formed by the fusion of two polar nuclei) of the embryo sac. This fusion involves three nuclei (one male gamete and two polar nuclei) and is therefore called triple fusion. It results in the formation of the triploid Primary Endosperm Nucleus (PEN), which develops into the endosperm, a nutritive tissue for the embryo.
iii) What are Allosomes?
Allosomes, also known as sex chromosomes, are the chromosomes that determine the sex of an individual. In humans, there are two types of allosomes: the X chromosome and the Y chromosome. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).
(OR)
35. b)
i) Explain the male reproductive system of Rabbit with a labeled diagram.
ii) Why is the circulation in man referred to as double circulation?
Answer:
i) Male Reproductive System of Rabbit:
[Diagram of Male Reproductive System of Rabbit]
The male reproductive system of a rabbit consists of the following organs:
- Testes: A pair of ovoid-shaped testes are located in the scrotal sacs, outside the abdominal cavity. They produce sperms and the male sex hormone, testosterone.
- Epididymis: A highly coiled tube where sperms are temporarily stored and mature.
- Vas Deferens: A tube that carries sperms from the epididymis to the urethra.
- Urethra: A common passage for both urine and semen. It extends through the penis.
- Accessory Glands: These include the prostate gland, Cowper's gland, and perineal gland. Their secretions mix with sperms to form semen, providing nourishment and a medium for sperm movement.
- Penis: An external copulatory organ used to transfer semen into the female's reproductive tract during mating.
ii) Why is the circulation in man referred to as double circulation?
The circulation in humans is called double circulation because the blood passes through the heart twice for each complete circuit of the body. This system consists of two distinct pathways:
- Pulmonary Circulation: This is the circuit between the heart and the lungs. Deoxygenated blood from the right ventricle is pumped to the lungs via the pulmonary artery. In the lungs, it gets oxygenated and returns to the left atrium of the heart via the pulmonary vein.
- Systemic Circulation: This is the circuit between the heart and the rest of the body (excluding lungs). Oxygenated blood from the left ventricle is pumped to all parts of the body through the aorta. After delivering oxygen and nutrients, the deoxygenated blood is collected by veins and returned to the right atrium of the heart.
This separation of oxygenated and deoxygenated blood allows for a highly efficient supply of oxygen to the body tissues, which is necessary to maintain a constant body temperature and meet high energy demands.