10th Science - Quarterly Exam 2024 - Original Question Paper with Solutions | Chengalpattu District
Solutions
Part - I (12 x 1 = 12)
Choose the correct answer and write it with the option code.
- Impulse is equal to
c) change of momentum
- The eye defect "presbyopia" can be corrected by
d) Bifocal lenses
- The value of universal gas constant
d) 8.31 Jmol⁻¹K⁻¹
- SI unit of resistance is
a) Ohm
- Which of the following represents 1 amu?
c) 1/12th of the mass of a C-12 atom
- What is the formula of Blue vitriol?
d) CuSO₄·5H₂O
- The process of coating the surface of metal with a thin layer of zinc is called
c) galvanization
- Kreb's cycle takes place in
b) mitochondrial matrix
- The segments of leech are known as
a) metameres
- Which of the correct sequence of blood flow
c) atrium → Ventricle → arteries → Vein (Note: This is a simplified representation. Arteries branch into capillaries, which then converge into veins that return blood to the atrium).
- Which hormone is secreted by the thymus gland?
b) Thymosin
- The _______ units form the backbone of the DNA.
d) Sugar phosphate
Part - II (7 x 2 = 14)
Answer any 7 questions. (Q.No. 22 is compulsory)
- State Newton's second law.
Newton's second law of motion states that the rate of change of momentum of a body is directly proportional to the applied external force and takes place in the direction of the force. Mathematically, F ∝ Δp/t, which leads to the equation F = ma (Force = mass × acceleration).
- Distinguish between ideal gas and real gas.
Ideal Gas Real Gas The intermolecular force of attraction is zero. The intermolecular force of attraction is not zero. The volume of the molecules is negligible compared to the volume of the gas. The volume of the molecules is not negligible. Obeys the ideal gas equation (PV=nRT) at all temperatures and pressures. Obeys the ideal gas equation only at high temperatures and low pressures. - What is rust? Give the equation for formation of rust.
Rust is hydrated ferric oxide (Fe₂O₃·xH₂O), a reddish-brown substance formed when iron corrodes by reacting with oxygen and water.
Equation: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (Rust) - Classify the following substances into deliquescent and hygroscopic: Con sulphuric acid, Copper sulphate pentahydrate, Silica gel, Calcium chloride and Gypsum salt.
Deliquescent: Calcium chloride
Hygroscopic: Concentrated sulphuric acid, Copper sulphate pentahydrate, Silica gel, Gypsum salt. - Write the reaction for photosynthesis.
The balanced chemical equation for photosynthesis is:
6CO₂ (Carbon dioxide) + 6H₂O (Water) →(in presence of Sunlight & Chlorophyll) C₆H₁₂O₆ (Glucose) + 6O₂ (Oxygen) - a) Give the common name of the Hirudinaria granulosa. b) What does CNS stand for?
a) The common name of Hirudinaria granulosa is the Indian cattle leech.
b) CNS stands for Central Nervous System. - Draw and label the diagram.
The diagram in the question paper depicts Guard cell in turgid condition.
Guard cells (swollen):
Stoma - What is bolting? How can it be induced artificially?
Bolting is the premature or elongated growth of an internodal stem just before flowering in plants that typically have a rosette-like growth habit (e.g., cabbage, beet).
Artificial Induction: It can be induced artificially by the application of plant hormones like Gibberellins. - What do you understand by the term phenotype and genotype?
Phenotype: The phenotype refers to the observable physical and biochemical characteristics of an organism, such as height, flower color, or blood type. It is determined by both the genotype and environmental factors.
Genotype: The genotype is the genetic constitution or makeup of an organism, representing the set of genes it carries. - The work done in moving a charge of 10C across two points in a circuit is 100J. What is the potential difference between the points?
Given:
- Work done (W) = 100 J
- Charge (Q) = 10 C
V = 100 J / 10 C
V = 10 Volts (V)
The potential difference between the points is 10 V.
Part - III (7 x 4 = 28)
Answer any 7 questions. (Q.No. 32 is compulsory)
- Define inertia. Give its classification.
Inertia: The inherent property of a body to resist any change in its state of rest or state of uniform motion, unless it is influenced by an external unbalanced force.
Classification: Inertia is classified into three types:- Inertia of Rest: The resistance of a body to change its state of rest. (e.g., A passenger jerks backward when a bus suddenly starts).
- Inertia of Motion: The resistance of a body to change its state of uniform motion. (e.g., An athlete runs a certain distance before a long jump to maintain motion).
- Inertia of Direction: The resistance of a body to change its direction of motion. (e.g., Passengers are pushed sideways when a bus takes a sharp turn).
- a) List any 2 properties of light. b) Why does the sky appear in blue colour?
a) Properties of light:
- Rectilinear Propagation: Light travels in a straight line in a homogenous medium.
- Reflection: Light bounces back when it strikes a polished surface.
- Refraction: Light bends when it travels from one medium to another.
- Scattering: Light is deflected in various directions by particles in its path.
- Match the items in column I to the items in column II.
Column I Column II Correct Match i) electric current volt i) → ampere
ii) → volt
iii) → ohm meter
iv) → wattii) potential difference ohm meter iii) specific resistance watt iv) electric power ampere - a) What happens when MgSO₄·7H₂O is heated? Write the appropriate equation. b) Define Solubility.
a) Heating of MgSO₄·7H₂O: When Magnesium sulphate heptahydrate (Epsom salt) is heated, it loses its water of crystallization and becomes anhydrous magnesium sulphate, a white crystalline solid.
Equation: MgSO₄·7H₂O(s) →(Heat) MgSO₄(s) + 7H₂O(g)
b) Solubility: Solubility is defined as the maximum amount of a solute (in grams) that can be dissolved in 100 grams of a solvent to form a saturated solution at a specific temperature. - Fill in the blanks and answer the Assertion/Reason question.
Fill in the blanks:
a) Atomic number forms the basis of the modern periodic table.
b) The chief ore of Aluminium is Bauxite (Al₂O₃·2H₂O).
Assertion and Reason:
c) Assertion: Magnesium is used to protect steel from rusting.
Reason: Magnesium is more reactive than iron.
Answer: i) A and R are correct. R explains the A. (Magnesium acts as a sacrificial anode because it is more reactive and corrodes preferentially, thereby protecting the steel). - Differentiate the following: aerobic and anaerobic respiration.
Feature Aerobic Respiration Anaerobic Respiration Oxygen Requirement Occurs in the presence of oxygen. Occurs in the absence of oxygen. Location Cytoplasm and Mitochondria. Only in the Cytoplasm. Breakdown of Glucose Complete oxidation. Incomplete oxidation. End Products Carbon dioxide (CO₂), Water (H₂O). Ethanol and CO₂ (in yeast) or Lactic acid (in muscles). Energy Yield High (approx. 36-38 ATP molecules). Low (only 2 ATP molecules). - List out the parasitic adaptations in leech.
Parasitic adaptations of leech (Hirudinaria) include:
- Suckers: Possesses anterior and posterior suckers for strong attachment to the host.
- Pharynx: A muscular pharynx is present for sucking blood from the host.
- Anticoagulant: The saliva contains hirudin, which prevents the clotting of blood, ensuring a continuous supply.
- Alimentary Canal: The crop is large and can store a large amount of blood, which is digested slowly.
- Anaerobic Respiration: Can respire anaerobically, which is useful when it is attached to a host.
- State whether true or false. a) The phloem is responsible for the translocation of food. b) When guard cells lose water the stomata opens. c) Bring out any two physiological activities of abscisic acid.
a) True. Phloem transports sugars (food) from the leaves to other parts of the plant.
b) False. When guard cells lose water, they become flaccid, and the stomata close.
c) Two physiological activities of abscisic acid (ABA):- Promotes Dormancy: It induces dormancy in buds and seeds, helping them survive unfavourable conditions.
- Stress Hormone: It causes the closure of stomata during water stress (drought) to reduce water loss through transpiration.
- Enumerate the functions of blood.
The main functions of blood are:
- Transport: It transports respiratory gases (O₂ and CO₂), digested food (nutrients), hormones, enzymes, and waste products (like urea).
- Regulation: It helps in regulating body temperature, pH (acid-base balance), and water balance.
- Protection: It protects the body from disease-causing pathogens through white blood cells (WBCs) and antibodies. It also prevents excessive blood loss through the process of clotting (platelets and clotting factors).
- a) Identify the bond between H and F in HF molecule. b) What property forms the basis of Identification? c) How does the property vary in periods and in groups?
a) The bond between Hydrogen (H) and Fluorine (F) in an HF molecule is a polar covalent bond.
b) The property that forms the basis for this identification is the difference in electronegativity between the two atoms. Fluorine is the most electronegative element, while hydrogen has a much lower electronegativity, leading to unequal sharing of electrons.
c) Variation of Electronegativity:- Across a Period (left to right): Electronegativity generally increases due to an increase in nuclear charge and a decrease in atomic size.
- Down a Group (top to bottom): Electronegativity generally decreases due to an increase in atomic size and shielding effect, which reduces the attraction of the nucleus for the bonding electrons.
Part - IV (3 x 7 = 21)
Answer in detail.
- What are the types of inertia? Give an example for each.
[Answered in Part III, Question 23. This is a detailed version.]
Inertia is the inherent property of a body to resist any change in its state of rest or uniform motion unless acted upon by an external force.
There are three types of inertia:1. Inertia of Rest
It is the inability of a body to change its state of rest by itself.
Example: When you vigorously shake the branches of a tree, some of the leaves and fruits get detached and fall down. This is because the branches come into motion while the leaves and fruits tend to remain at rest due to inertia of rest. This causes them to detach.
2. Inertia of Motion
It is the inability of a body to change its state of uniform motion by itself.
Example: When a bus is moving, a passenger inside also moves along with it. If the driver applies the brakes suddenly, the bus comes to a stop, but the passenger's body continues to move forward due to inertia of motion. This is why passengers are jerked forward when a moving bus stops.
3. Inertia of Direction
It is the inability of a body to change its direction of motion by itself.
Example: When a car moving in a straight line takes a sharp turn to the right, the passengers are pushed towards the left. This is because the car changes its direction, but the passengers' bodies tend to continue moving in the original straight-line direction due to inertia of direction.
[OR]
Derive the ideal gas equation.The ideal gas equation is an equation of state for a hypothetical ideal gas. It is derived by combining three empirical gas laws:
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 .......... (1)
2. Charles's 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 .......... (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 .......... (3)
Combining the three laws: By combining equations (1), (2), and (3), we get:V ∝ nT/P
This can be written as:V = R (nT/P)
where R is a constant of proportionality called the Universal Gas Constant. Rearranging the equation, we get the ideal gas equation:PV = nRT
The value of R is constant for all gases and is approximately 8.314 J mol⁻¹ K⁻¹. - a) Give the salient features of "Modern atomic theory". [5 marks] b) Calculate the molecular mass of CO₂. [2 marks]
a) Salient Features of Modern Atomic Theory
- Atom is no longer indivisible: An atom is composed of subatomic particles like protons, neutrons, and electrons.
- Atoms of the same element may not be identical: The existence of isotopes (e.g., ¹H, ²H, ³H) proves that atoms of the same element can have different mass numbers.
- Atoms of different elements may be identical: The existence of isobars (e.g., ⁴⁰Ar, ⁴⁰K, ⁴⁰Ca) proves that atoms of different elements can have the same mass number.
- Atom is the smallest particle in a chemical reaction: The atom is the smallest unit of matter that takes part in a chemical reaction.
- Mass can be converted into energy: The mass of an atom can be converted into energy according to Einstein's equation, E = mc². This is not conserved separately in nuclear reactions.
- The ratio of atoms in a molecule may not be simple: Atoms may combine in a ratio that is not simple whole numbers, as seen in complex organic molecules like sucrose (C₁₂H₂₂O₁₁).
b) Calculation of molecular mass of CO₂
To calculate the molecular mass of Carbon Dioxide (CO₂), we need the atomic masses of Carbon (C) and Oxygen (O).
- Atomic mass of Carbon (C) ≈ 12.01 u
- Atomic mass of Oxygen (O) ≈ 16.00 u
The formula for CO₂ indicates one Carbon atom and two Oxygen atoms.
Molecular Mass of CO₂ = (1 × Atomic mass of C) + (2 × Atomic mass of O)
= (1 × 12.01) + (2 × 16.00)
= 12.01 + 32.00
= 44.01 u (or g/mol for molar mass)
[OR]
Write a note on Various factors affecting solubility.Solubility is the ability of a solute to dissolve in a solvent. It is affected by several factors:1. Nature of the Solute and Solvent
This is governed by the principle "like dissolves like".
- Polar solutes (like salt, NaCl) tend to dissolve in polar solvents (like water, H₂O).
- Non-polar solutes (like grease, oil) tend to dissolve in non-polar solvents (like ether, CCl₄).
2. Temperature
The effect of temperature depends on the state of the solute and solvent.
- Solids in Liquids: For most solid solutes, solubility increases as the temperature increases (e.g., dissolving sugar in hot water). However, for some substances like cerium sulfate (Ce₂(SO₄)₃), solubility decreases with an increase in temperature.
- Gases in Liquids: The solubility of gases in liquids decreases as the temperature increases. This is why boiled water has a "flat" taste, as dissolved gases like oxygen have escaped.
3. Pressure
- Solids and Liquids: A change in pressure has a negligible effect on the solubility of solid and liquid solutes.
- Gases in Liquids: The solubility of a gas in a liquid is directly proportional to the pressure of the gas over the liquid. This is stated by Henry's Law. For example, carbonated drinks are bottled under high pressure to increase the solubility of CO₂ gas in the liquid.
- With a neat labelled diagram explain the structure of a neuron.
A neuron (or nerve cell) is the structural and functional unit of the nervous system. It consists of three main parts:
[Image of a Neuron]
A diagram showing the main parts: Dendrites, Cell Body (Cyton) with a Nucleus, Axon, Myelin Sheath, Nodes of Ranvier, and Axon Terminals.1. Cell Body (Cyton or Soma)
- It is the main part of the neuron, with a large, central nucleus and cytoplasm.
- The cytoplasm contains characteristic, deeply stained particles called Nissl's granules, which are involved in protein synthesis.
- It controls all the metabolic activities of the neuron.
2. Dendrites
- These are short, branched cytoplasmic extensions that arise from the cell body.
- They receive nerve impulses from other neurons or sensory receptors and transmit them towards the cell body.
3. Axon
- It is a single, long, slender projection that arises from the cell body.
- It is responsible for carrying nerve impulses away from the cell body to other neurons or to effector organs (muscles or glands).
- The axon is often covered by a protective sheath called the myelin sheath, which is made of Schwann cells. The myelin sheath acts as an insulator and speeds up the transmission of nerve impulses.
- The myelin sheath is not continuous; it has gaps called the Nodes of Ranvier, where the nerve impulse "jumps" from one node to the next (saltatory conduction).
- The end of the axon branches into fine filaments called axon terminals, which end in synaptic knobs. These knobs release neurotransmitters to transmit the signal to the next neuron.
[OR]
With a neat labelled diagram describe the parts of a typical angiospermic ovule.An ovule is the structure within the ovary of a flowering plant that contains the female reproductive cell and, after fertilization, develops into a seed. A typical anatropous ovule consists of the following parts:
[Image of an Anatropous Ovule]
A diagram showing the ovule attached to the ovary wall, with labels for Funiculus, Hilum, Integuments (outer and inner), Micropyle, Chalaza, Nucellus, and Embryo sac containing the egg cell, synergids, polar nuclei, and antipodal cells.- Funiculus (or Funicle): The stalk that attaches the ovule to the placenta in the ovary wall.
- Hilum: The point of attachment where the body of the ovule fuses with the funiculus.
- Integuments: One or two protective layers that surround the main body of the ovule, leaving a small opening. After fertilization, they develop into the seed coat.
- Micropyle: A small opening at the apex of the integuments through which the pollen tube usually enters the ovule for fertilization.
- Chalaza: The basal part of the ovule, opposite the micropyle, where the nucellus and integuments originate.
- Nucellus: A mass of parenchymatous tissue that encloses the embryo sac. It provides nourishment to the developing embryo sac.
- Embryo Sac (Female Gametophyte): A large, oval cell located within the nucellus that contains the female gamete. A mature embryo sac typically contains:
- Egg Apparatus: Located at the micropylar end, it consists of one egg cell and two flanking synergids.
- Antipodal Cells: Three cells located at the chalazal end.
- Central Cell: The large central cell containing two polar nuclei, which fuse to form the secondary nucleus before fertilization.