Search Previous Year Questions

The correct answer is Supporting and providing structural framework to body parts.

Key Points

• Connective tissue is the most diverse and abundant type of tissue in the human body, primarily functioning to bind, support, and protect organs while providing a structural framework.
• Unlike other tissues, it consists of a relatively small number of cells (such as fibroblasts, adipocytes, and chondrocytes) embedded in a large volume of extracellular matrix (ECM).
• The extracellular matrix is composed of ground substance and protein fibers, including collagen for tensile strength, elastin for elasticity, and reticular fibers for structural support.
• Physiologically, connective tissue develops from the mesoderm and ranges from fluid types like blood (linking systems) to solid types like bone (providing the skeletal scaffold).
• Specialized connective tissues like ligaments connect bones to bones, while tendons connect muscles to bones, ensuring mechanical stability during movement.

 Additional Information

• Nervous Tissue
• Function: Responsible for conducting electrical impulses (action potentials) and rapid communication between body parts.
• Components: Consists of neurons (excitable cells) and neuroglia (supporting cells) located in the brain, spinal cord, and peripheral nerves.
• Muscular Tissue
• Function: Specialized for contraction and relaxation to produce force, enabling locomotion and internal movements.
• Types: Includes skeletal muscle (voluntary), smooth muscle (involuntary), and cardiac muscle (found in the heart).
• Epithelial Tissue
• Function: Forms protective barriers, linings, and is involved in secretion and selective absorption of nutrients.
• Location: Found in the epidermis of the skin and the inner linings of the digestive tract and respiratory system.

The correct answer is soil ; soil.

Key Points

• Plants require 16 essential nutrients for proper growth, which are obtained from air, water, and soil. While air provides Carbon and Oxygen, and water provides Hydrogen, the remaining 13 nutrients are supplied by the soil.
• Macro-nutrients are those elements required by plants in relatively large quantities for the formation of plant biomass and cellular structures. Out of the nine macro-nutrients, Nitrogen (N), Phosphorus (P), Potassium (K), Calcium (Ca), Magnesium (Mg), and Sulphur (S) are primarily absorbed from the soil.
• Micro-nutrients, or trace elements, are essential for enzymatic reactions and metabolic functions but are needed in very minute quantities. The soil provides all seven primary micro-nutrients: Iron (Fe), Manganese (Mn), Boron (B), Zinc (Zn), Copper (Cu), Molybdenum (Mo), and Chlorine (Cl).
• The root system absorbs these minerals from the soil solution through the process of ion exchange. These nutrients are critical for maintaining the osmotic balance and metabolic activity of the plant.

 Additional Information

• Nutrient Categories:
• Critical Macro-nutrients: Nitrogen is a major component of chlorophyll and proteins. Phosphorus is essential for ATP and DNA synthesis. Potassium helps in stomatal regulation.
• Specific Micro-nutrient Roles: Zinc is necessary for auxin synthesis, while Iron is a constituent of ferredoxin and cytochromes involved in the electron transport chain.
• Soil Composition: The ability of soil to supply these nutrients depends on its pH level, organic matter content, and cation exchange capacity.

The correct answer is Carbon is less reactive than magnesium.

Key Points

• Magnesium is placed above carbon in the reactivity series, making it more reactive than carbon.
• Carbon can reduce the oxides of metals that are less reactive than carbon, such as zinc, iron, and lead, but it cannot reduce magnesium oxide (MgO).
• Magnesium oxide (MgO) is a highly stable compound with a strong ionic bond, requiring electrolysis rather than carbon reduction for the extraction of magnesium.
• Industrial extraction of magnesium is carried out by the electrolysis of molten magnesium chloride (MgCl₂), not by heating magnesium oxide with carbon.
• Hence, the attempt fails because carbon is less reactive than magnesium.

Additional Information

• Reactivity Series:
• Potassium, Sodium, Calcium, Magnesium, Aluminium, Carbon, Zinc, Iron, Lead, Copper, Silver, Gold (decreasing order of reactivity).
• Metals above carbon in the series cannot be extracted by carbon reduction.
• Carbon Reduction:
• Carbon acts as a reducing agent by removing oxygen from metal oxides.
• It is effective only for metals that are less reactive than carbon.
• Extraction of Magnesium:
• Commercially obtained by the electrolysis of molten magnesium chloride.
• This process produces magnesium at the cathode and chlorine gas at the anode.
• Examples of Metals Extracted by Carbon Reduction:
• Iron from hematite (Fe₂O₃).
• Zinc from zinc oxide (ZnO).
• Lead from lead oxide (PbO).
• Highly Reactive Metals:
• Potassium, Sodium, Calcium, Magnesium, and Aluminium are generally extracted by electrolysis because chemical reducing agents like carbon cannot displace them from their compounds.

The correct answer is Only 1 and 3.

Key Points

• Statement 1: Proposed by J.J. Thomson in 1898, this model suggests the atom is a positively charged sphere with electrons embedded throughout, ensuring the atom remains electrically neutral. Hence, statement 1 is correct.
• Statement 2: This model assumed mass was distributed uniformly; however, the nucleus and neutrons were not yet discovered. The nucleus was identified by Ernest Rutherford in 1911, and neutrons by James Chadwick in 1932. Hence, statement 2 is incorrect.
• Statement 3: The model is famously visualized as a watermelon, where the red part represents the positive charge and the seeds represent the electrons, or alternatively as a plum pudding. Hence, statement 3 is correct.

 Additional Information

• J.J. Thomson (1856−1940):
• He was a British physicist and was awarded the Nobel Prize in Physics in 1906.
• He is credited with the discovery of the electron, which was the first subatomic particle identified.
• His experiments with cathode ray tubes led to the determination of the charge-to-mass ratio (e/m) of electrons.
• Limitations of the Model:
• It failed to explain the stability of the atom and the alpha-particle scattering results.
• It was eventually superseded by the Rutherford Nuclear Model and the Bohr Model.

The correct answer is AgNO3 + NaCl → AgCl + NaNO3.

Key Points

• A double displacement reaction, also known as a metathesis reaction, occurs when two ionic compounds react and exchange their cations and anions to form two entirely new compounds.
• In the reaction AgNO3 + NaCl → AgCl + NaNO3, the Silver (Ag⁺) ion from Silver Nitrate exchanges partners with the Sodium (Na⁺) ion from Sodium Chloride.
• The Nitrate (NO3⁻) ion and Chloride (Cl⁻) ion switch their respective positions, resulting in the formation of Silver Chloride and Sodium Nitrate.
• This specific example is also categorized as a precipitation reaction because AgCl is an insoluble solid that falls out of the solution as a white precipitate.
• The general chemical equation for this type of reaction is represented as AB + CD → AD + CB, where A and C are cations and B and D are anions.

 Additional Information

• Reaction Types in Options:
• Combination Reactions: The reactions H2 + Cl2 → 2HCl, 2Mg + O2 → 2MgO, and Na2O + H2O → 2NaOH are all examples of combination (synthesis) reactions where two or more reactants combine to form a single product.
• Oxidation of Magnesium: The reaction 2Mg + O2 → 2MgO is also an oxidation reaction and a combustion reaction characterized by the intense release of light and heat.
• Formation of Bases: The reaction Na2O + H2O → 2NaOH demonstrates how metallic oxides (basic oxides) react with water to form metal hydroxides, which are strong alkalis.
• Hydrochloric Acid Synthesis: The direct combination of Hydrogen and Chlorine gas is a fundamental method for producing Hydrogen Chloride, which becomes hydrochloric acid when dissolved in water.

The correct answer is Simple columnar epithelium.

Key Points

• Simple columnar epithelium consists of a single layer of tall, slender cells with nuclei usually located near the basal surface.
• This tissue is primarily found lining the digestive tract, specifically the stomach, small intestine, and large intestine, where it performs critical functions of secretion and absorption.
• In the human intestine, these cells are specialized with microvilli on their apical surface, which significantly increases the surface area available for the absorption of nutrients and water.
• The presence of goblet cells interspersed within this epithelium allows for the secretion of mucus, which lubricates the intestinal lining and protects it from digestive enzymes.

 Additional Information

• Simple squamous epithelium:
• Composed of a single layer of flat, scale-like cells.
• Its thinness allows for rapid diffusion and filtration.
• It is predominantly found in the alveoli of the lungs, the lining of blood vessels (endothelium), and the Bowman's capsule in kidneys.
• Simple cuboidal epithelium:
• Consists of cube-shaped cells with a central spherical nucleus.
• Commonly functions in secretion and absorption within kidney tubules, thyroid follicles, and the surface of the ovaries.
• Stratified squamous epithelium:
• Comprised of multiple layers of cells, with the outermost layer being flat.
• Its primary function is protection against mechanical stress and chemical abrasion.
• It is found in the skin (keratinized) and the lining of the mouth and esophagus (non-keratinized).

The correct answer is The gravitational force increases with the product of the masses and decreases with the square of the distance between them..

Key Points

• The Universal Law of Gravitation, formulated by Sir Isaac Newton in 1687, describes the attractive force between any two objects with mass in the universe.
• According to this law, the magnitude of the force (F) is directly proportional to the product of the masses of the two interacting objects (\( m_1 \times m_2 \)). Hence, statement 4 is partially correct regarding mass proportionality.
• The law further specifies that the force is inversely proportional to the square of the distance (\( r^2 \)) between the centers of the two objects. This is known as the inverse-square law. Hence, statement 4 is fully correct.
• Mathematically, the relationship is expressed as \( F = G \frac{m_1 m_2}{r^2} \), where G represents the Universal Gravitational Constant.
• The force acts along the line joining the centers of the two masses, making it a central force that is always attractive in nature.

 Additional Information

• Universal Gravitational Constant (G):
• The value of G is constant throughout the universe and is approximately \( 6.674 \times 10^{-11} \text{ N m}^2 \text{ kg}^{-2} \).
• This constant was first accurately measured by Henry Cavendish in 1798 using a torsion balance.
• Properties of Gravitational Force:
• It is the weakest of the four fundamental forces of nature but has an infinite range.
• It does not depend on the medium between the two objects.
• It obeys Newtons Third Law of Motion, as the forces exerted by the two bodies on each other are equal in magnitude and opposite in direction.
• It is a conservative force, meaning the work done by gravity depends only on the initial and final positions, not the path taken.

The correct answer is Both (i) and (iii).

Key Points

• The magnetic field lines around a straight current-carrying conductor are in the form of concentric circles that are centered on the wire and exist in a plane perpendicular to the wire. Hence, statement (i) is correct.
• Magnetic field lines never intersect each other because if they did, it would mean that at the point of intersection, a magnetic compass would point in two different directions simultaneously, which is physically impossible. Hence, statement (ii) is incorrect.
• The magnitude of the magnetic field produced by a straight wire decreases as the distance from the wire increases. To represent this weakening field intensity graphically, the circular field lines are drawn farther apart as the distance from the conductor increases. Hence, statement (iii) is correct.

 Additional Information

• Right-Hand Thumb Rule:
• This rule is used to determine the direction of magnetic field lines.
• If the thumb of the right hand points in the direction of the electric current, the curled fingers indicate the direction of the magnetic field.
• Mathematical Relation:
• The magnetic field strength B is directly proportional to the current (I) passing through the wire.
• The magnetic field strength B is inversely proportional to the distance (r) from the wire, represented by the relationship B ∝ I / r.
• Oersted's Discovery:
• Hans Christian Oersted first observed in 1820 that a compass needle is deflected when placed near a wire carrying an electric current, proving that electricity and magnetism are related.

The correct answer is Straight line parallel to the x-axis.

Key Points

• Uniform velocity occurs when an object covers equal displacements in equal intervals of time, implying that both speed and direction remain constant throughout the motion.
• In a velocity-time (v-t) graph, time is conventionally plotted on the horizontal x-axis, while velocity is plotted on the vertical y-axis.
• Because the velocity does not change with respect to time, the y-coordinate (representing velocity) remains fixed at a specific value for every point on the time axis.
• Geometrically, a set of points sharing the same ordinal value (constant height) results in a horizontal straight line that never intersects the x-axis unless the velocity is zero.
• The slope of a velocity-time graph represents the acceleration of the object; for uniform velocity, the change in velocity is zero, resulting in a zero slope, which corresponds to a line parallel to the x-axis.

 Additional Information

• Displacement from Graph:
• The area under the curve in a velocity-time graph provides the total displacement of the object. For uniform motion, this area is a rectangle with the formula Displacement = Velocity × Time.
• Straight line passing through the origin:
• This specific graph shape represents uniform acceleration where the object starts from a state of rest (initial velocity is zero). The velocity increases linearly with time.
• Curve:
• A non-linear or curved line on a v-t graph indicates variable acceleration, where the rate of change of velocity is not constant over time.
• Vertical line:
• A line parallel to the y-axis is physically impossible in kinematics as it would suggest an object possesses multiple velocities at the exact same instant or has infinite acceleration.

The correct answer is Apparent weight.

Key Points

• When a solid object is immersed in water, it experiences an upward force known as the buoyant force or upthrust. This phenomenon is governed by Archimedes’ Principle, which states that the upward buoyant force is equal to the weight of the fluid displaced by the object.
• The apparent weight is the net downward force acting on the object while it is submerged. It is calculated by the formula: Apparent Weight = True Weight − Buoyant Force.
• Because the buoyant force acts in the opposite direction to the force of gravity (true weight), the effective weight of the object decreases, making it feel lighter than its actual weight in a vacuum or air.
• The magnitude of this decrease depends directly on the density of the fluid and the volume of the displaced fluid. In water, which has a high density compared to air, this reduction is significant and easily measurable.

 Additional Information

• Mass:
• It is an intrinsic property of matter representing the quantity of atoms and molecules in an object.
• Mass is a scalar quantity and remains constant regardless of the object's location or the medium it is placed in.
• Density:
• Defined as the mass per unit volume of a substance. For a solid, non-porous object, neither its total mass nor its physical volume changes upon immersion.
• Therefore, the density remains invariant during the process of immersion in water.
• Buoyant Force:
• This force is an interaction between the fluid and the object. It does not decrease; rather, it is the exerted pressure from the fluid that creates the upward lift.
• It is calculated as ρ × g × V, where ρ is the density of the fluid, g is acceleration due to gravity, and V is the submerged volume.