Ch 1Laws of Motion
5-Mark Questions
Define inertia. Give its classification.
Inertia is the inherent property of an object that resists any change in its state of rest or uniform motion along a straight line, unless acted upon by an external unbalanced force. This means an object at rest will stay at rest, and an object in motion will continue in motion with the same velocity, unless a net force intervenes. Inertia is directly proportional to the mass of the object; a more massive object has more inertia. …
Differentiate mass and weight.
Mass is the amount of matter in a body. It is a scalar quantity, its SI unit is kilogram (kg), and it remains the same everywhere. Weight is the gravitational force acting on a body. It is a vector quantity, its SI unit is newton (N), and it is given by W = mg. Weight changes from place to place because g changes.
2-Mark Questions
Classify the types of force based on their application.
Forces can be classified into two main types based on whether they require physical contact between the interacting bodies or not. The first type is contact force, which is a force that acts only when two bodies are in direct physical contact. Examples of contact forces include frictional force, which opposes motion between surfaces in contact; normal force, which is perpendicular to the surface of contact; and muscular force, which is applied by the muscles of living beings. …
If a 5 N and a 15 N forces are acting opposite to one another. Find the resultant force and the direction of action of the resultant force
Let the forces be 5 N and 15 N acting in opposite directions. Resultant magnitude = |15 N - 5 N| = 10 N. Direction: toward the 15 N force (the larger force).
It is the quantity of matter contained in the body
Mass is defined as the quantity of matter contained within a body. It is a fundamental property of matter and is independent of external conditions such as temperature, pressure, or location. The SI unit for mass is the kilogram (kg). Mass is typically measured using a physical balance, which compares the unknown mass to known standard masses, or an electronic balance, which uses a load cell to measure the force exerted by the mass and converts it into a mass reading. A larger mass indicates a greater amount of matter.
1-Mark Questions (MCQ)
“Wearing helmet and fastening the seat belt is highly recommended for safe journey” Justify your answer using Newton’s laws of motion.
1) State laws used: Newton's 1st law (inertia) and 2nd law (F = ma) plus impulse-momentum (Delta p = F_avg Delta t). 2) Describe the hazard: In a sudden stop or collision passenger's velocity v must change to zero (Delta v = -v); momentum change Delta p = mDelta v. 3) Use formula: average stopping force F_avg = mDelta v/Delta t. For fixed m and Delta v, larger Delta t -> smaller F_avg. 4) Apply to helmet: helmet cushions impact, increases Delta t and impact distance, so F_avg on skull decreases -> less injury. …
Ch 2Optics
5-Mark Questions
State Snell’s law.
Snell's law states that, for a given pair of media, the ratio of sine of the angle of incidence to sine of the angle of refraction is constant, when the angles are measured from the normal to the surface. It can be written as sin i / sin r = n2 / n1, or n1 sin i = n2 sin r, where n1 and n2 are the refractive indices of the two media, i is the angle of incidence and r is the angle of refraction.
Draw a ray diagram to show the image formed by a convex lens when the object is placed between F and 2F.
Ray diagram construction steps: (i) Draw the principal axis and mark the convex lens, F and 2F on both sides. Place the object AB between F and 2F on the left side. (ii) From the top A, draw a ray parallel to the principal axis; after refraction it passes through the focus on the other side. (iii) From A, draw another ray through the optical centre; it goes undeviated. (iv) The refracted rays meet at A' beyond 2F on the right side. Draw A'B' perpendicular to the principal axis. Thus the image is formed beyond 2F, and it is real, inverted and magnified. …
2-Mark Questions
What is refractive index?
Refractive index is the ratio of the speed of light in vacuum to the speed of light in a medium. It is given by μ = c/v, where c is the speed of light in vacuum and v is the speed of light in the medium. Refractive index has no unit.
Define dispersion of light
Dispersion of light is the phenomenon observed when a beam of white light passes through a transparent medium, such as a glass prism or water droplets, and splits into its constituent colours. This splitting occurs because each colour of light, corresponding to a different wavelength, travels at a slightly different speed within the medium. Consequently, each colour is refracted at a slightly different angle. Violet light, having the shortest wavelength, is deviated the most, while red light, with the longest wavelength, is deviated the least. …
State Rayleigh’s law of scattering
Rayleigh's law of scattering describes how light is scattered by particles that are much smaller than the wavelength of the light, such as molecules of gas in the atmosphere. The law states that the intensity of scattered light is inversely proportional to the fourth power of its wavelength. Mathematically, this can be expressed as: Intensity of scattering ∝ 1/λ⁴, where λ is the wavelength of the light. …
1-Mark Questions (MCQ)
While doing an experiment for the determination of focal length of a convex lens, Raja Suddenly dropped the lens. It got broken into two halves along the axis. If he continues his experiment with the same lens, (a) can he get the image? (b) Is there any change in the focal length?
(a) Yes, he can still get the image using one half of the broken convex lens. (b) There is no change in the focal length because the curvature of the lens surfaces does not change. However, the intensity or brightness of the image will be reduced because less light passes through the broken lens.
Ch 3Thermal Physics
5-Mark Questions
Distinguish between linear, cubical and superficial expansion.
Linear expansion: change in length of a body due to change in temperature. Formula: Delta L = α L0 Delta T; unit of α is K^-1. Cubical expansion: change in volume of a body due to change in temperature. Formula: Delta V = γ V0 Delta T; unit of γ is K^-1 and, for solids, γ is approximately 3α. Superficial expansion: change in area of a body due to change in temperature. Formula: Delta A = β A0 Delta T; unit of β is K^-1 and, for solids, β is approximately 2α.
Distinguish between ideal gas and real gas.
Ideal gas: It obeys the ideal gas equation PV = nRT. Its molecules are assumed to have negligible volume and no intermolecular force of attraction. Real gas: Its molecules have finite volume and intermolecular force of attraction. It obeys PV = nRT only approximately, especially at low pressure and high temperature. At high pressure and low temperature, it deviates from ideal behaviour.
2-Mark Questions
Define one calorie.
Definition: 1 cal = heat needed to raise 1 g water by 1 °C. Conversion: 1 cal = 4.184 J (approx).
Also called longitudinal expansion
Linear expansion is also called longitudinal expansion. Its formula is Delta L = α L0 Delta T, where Delta L is change in length, L0 is original length, Delta T is temperature change, and α is the coefficient of linear expansion with unit K^-1.
Also called as superficial expansion
Areal expansion is also called superficial expansion. Its formula is Delta A = β A0 Delta T, so β = Delta A/(A0 Delta T). For solids, β is approximately 2α. Unit: K^-1.
1-Mark Questions (MCQ)
Explain the experiment of measuring the real and apparent expansion of a liquid with a neat diagram.
Apparatus: small flask (or bulb) fitted with a narrow capillary tube, wooden or metal stand, scale/ruled glass behind the capillary (for marking heights), thermometer, burner. Procedure: 1. Fill the flask with the liquid up to a mark on the capillary and glass scale. Mark the initial level as L1 at room temperature and note the initial temperature T1. 2. Heat the flask gently. As the vessel (container) expands its internal volume increases and the liquid level in the capillary may fall slightly. When this fall is observed, mark this level as L2. 3. …
Ch 4Electricity
5-Mark Questions
Define electric potential and potential difference.
Electric potential at a point is the work done per unit positive charge in bringing the charge from infinity to that point. Formula: V = W/q. Its SI unit is volt; 1 V = 1 J C^-1. Potential difference between two points is the work done per unit positive charge in moving the charge from one point to another. Formula: V = W/q, measured in volt.
Distinguish between the resistivity and conductivity of a conductor.
Resistivity (ρ): It is the resistance of a conductor of unit length and unit area of cross-section. Formula: ρ = RA/l. Unit: ohm metre (Ω m). It measures how strongly a material opposes current. Conductivity (σ): It is the reciprocal of resistivity. Formula: σ = 1/ρ. Unit: siemens per metre (S m^-1). It measures how easily a material allows current to pass.
2-Mark Questions
Define the unit of current.
Definition: 1 ampere = 1 coulomb of charge passing a point per 1 second. Formula: I = Q/t. Thus 1 A = 1 C / 1 s. (Symbol for ampere: A.)
What happens to the resistance, as the conductor is made thicker?
Start from R = ρL/A. For fixed ρ and L, R proportional to 1/A. For a circular wire A = pir^2, so increasing thickness (radius) increases A and thus reduces R. Conclusion: Resistance decreases when the conductor is made thicker.
Why is tungsten metal used in bulbs, but not in fuse wires?
Tungsten metal is primarily used for the filaments in electric bulbs because of its exceptionally high melting point (around 3422 °C) and its ability to withstand high temperatures without vaporizing quickly. When electric current passes through the tungsten filament, it heats up to a very high temperature, causing it to glow and emit light. In contrast, fuse wires are designed to protect electrical circuits from overcurrents. They are made of materials with low melting points, such as alloys of lead and tin. …
1-Mark Questions (MCQ)
A piece of wire of resistance 10 ohm is drawn out so that its length is increased to three times its original length. Calculate the new resistance.
Given initial R = 10 Ω. Let initial length = L and area = A. R = ρL/A = 10 Ω. New length = 3L. With constant volume, new area = A/3. R' = ρ(3L)/(A/3) = 9 (ρL/A) = 9R = 9 x 10 Ω = 90 Ω.
Ch 5Acoustics
5-Mark Questions
A source of sound is travelling with a velocity 40 km/h towards an observer and emits a sound of frequency 2000 Hz. If the velocity of sound is 1220 km/h, then the apparent frequency heard by the observer is 2068 Hz.
2068 Hz. For a source moving towards a stationary observer, n' = [v/(v - vs)] n = [1220/(1220 - 40)] x 2000 = 2068 Hz approximately.
What are the factors that affect the speed of sound in gases?
(i) Effect of density: Velocity of sound in a gas is inversely proportional to the square root of density, so it decreases as density increases. (ii) Effect of temperature: Velocity of sound in a gas increases with temperature. For air, vT = v0 + 0.61T, where v0 = 331 m s-1 at 0°C. (iii) Effect of relative humidity: When humidity increases, the speed of sound increases because humid air has lower effective density than dry air.
2-Mark Questions
Rapid back and forth motion of a particle about its mean position is called Vibration
Vibration. Vibration is defined as the rapid, repetitive back and forth motion of a particle or object around its equilibrium or mean position. This oscillatory movement is a fundamental concept in the study of waves and sound. The speed and amplitude of these vibrations determine characteristics of the resulting wave, such as frequency and loudness.
If the energy in a longitudinal wave travels from south to north, the particles of the medium would be vibrating in both north and south
Both north and south. In a longitudinal wave, the particles of the medium oscillate back and forth in a direction parallel to the direction in which the wave is traveling. If the energy of a longitudinal wave is propagating from south to north, the individual particles of the medium will move both towards the north and towards the south from their mean positions, creating compressions and rarefactions along the path of the wave.
A whistle giving out a sound of frequency 450 Hz, approaches a stationary observer at a speed of 33 m s-1. The frequency heard by the observer is (speed of sound = 330 m s-1) 500 Hz.
500 Hz. For a source moving towards a stationary observer, apparent frequency n' = [v/(v - vs)] n = [330/(330 - 33)] x 450 = 500 Hz.
1-Mark Questions (MCQ)
When sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound remain the same. Do you hear an echo sound on a hotter day? Justify your answer.
On a hotter day, the speed of sound increases, so the echo returns in a shorter time: t = 2d/v. If the fixed distance is just enough for an echo on a cooler day, the return time may fall below 0.1 s and the echo will not be heard distinctly. If the reflecting surface is far enough that t remains at least 0.1 s, the echo can still be heard.
Ch 6Nuclear Physics
5-Mark Questions
Arrange the following in the chronological order of discovery
Chronological order: radioactivity (1896), discovery of radium (1898), artificial radioactivity (1934), nuclear reactor (1942).
Explain controlled and uncontrolled chain reactions.
A controlled chain reaction is a nuclear reaction where the rate of fission is carefully managed. In this process, the number of neutrons available to cause further fission is kept constant, typically at one neutron per fission event. This is achieved by absorbing excess neutrons using materials like cadmium or boron. The steady release of energy from a controlled chain reaction is harnessed and utilized in nuclear reactors for power generation. In contrast, an uncontrolled chain reaction is characterized by a rapid multiplication of neutrons. …
2-Mark Questions
Arrange in descending order, on the basis of their penetration power
The penetration power of different types of radiation refers to their ability to pass through matter. In descending order, meaning from highest penetration power to lowest, the arrangement is as follows: Cosmic rays possess the highest penetration power among these, capable of traversing significant distances through various materials. Gamma rays follow, being highly energetic electromagnetic radiation that can penetrate deeply into substances. Beta rays, which are fast-moving electrons or positrons, have moderate penetration power, less than gamma rays but more than alpha rays. …
Ra-226 experiences three alpha decays. Find the number of neutrons in the daughter element.
In three alpha decays, mass number decreases by 12 and atomic number decreases by 6. Daughter nucleus: A = 226 - 12 = 214 and Z = 88 - 6 = 82. Number of neutrons = A - Z = 214 - 82 = 132.
A cobalt specimen emits induced radiation of 75.6 millicurie per second. Convert this disintegration in to becquerel (one curie = 3.7 \times 1010 Bq)
1 curie = 3.7 x 10^10 Bq. 75.6 millicurie = 75.6 x 10^-3 curie. Activity = 75.6 x 10^-3 x 3.7 x 10^10 = 2.7972 x 10^9 Bq.
1-Mark Questions (MCQ)
Cell phone towers should be placed far away from residential areas. Why?
Cell phone towers emit radio-frequency electromagnetic waves. To reduce continuous exposure and possible health concerns, they should be placed away from densely populated residential areas.
Ch 7Atoms and Molecules
5-Mark Questions
Give the salient features of “Modern atomic theory”.
The salient features of modern atomic theory are: (i) Atom is divisible into subatomic particles such as electrons, protons and neutrons. (ii) Atoms of the same element may have different atomic masses; these are isotopes, such as Cl-35 and Cl-37. (iii) Atoms of different elements may have the same mass number; these are isobars, such as Ar-40 and Ca-40. (iv) Atoms of one element can be transmuted into atoms of another element by nuclear reactions. (v) Atom is the smallest particle that takes part in a chemical reaction. (vi) Mass can be converted into energy in nuclear reactions, E = mc^2.
Derive the relationship between Relative molecular mass and Vapour density.
Vapour density is the ratio of the mass of a certain volume of a gas or vapour to the mass of an equal volume of hydrogen under the same conditions. By Avogadro's law, equal volumes contain equal number of molecules. Since hydrogen is diatomic, the mass of one molecule of hydrogen is twice the mass of one hydrogen atom. Therefore, vapour density = molecular mass/2. Hence, relative molecular mass = 2 x vapour density.
2-Mark Questions
Define: Relative atomic mass.
The relative atomic mass of an element is a dimensionless quantity that represents the average mass of atoms of that element compared to a standard reference. Specifically, it is defined as the ratio of the average mass of one atom of the element to one-twelfth (1/12) of the mass of an atom of the carbon-12 isotope. Carbon-12 is used as the standard because it is abundant and stable. This definition allows for a consistent and comparable scale for the masses of different elements, facilitating stoichiometric calculations and understanding chemical composition. …
Write the different types of isotopes of oxygen and its percentage abundance.
Oxygen, a vital element for life, exists in nature as a mixture of three stable isotopes. These isotopes have the same number of protons but differ in their number of neutrons, leading to slightly different atomic masses. The most abundant isotope is Oxygen-16 (¹⁶O), which has a mass of approximately 15.9949 atomic mass units (amu) and constitutes about 99.757% of naturally occurring oxygen. The second isotope is Oxygen-17 (¹⁷O), with a mass of approximately 16.9991 amu, and it is present in a very small abundance of about 0.038%. …
Define: Atomicity
Atomicity refers to the number of atoms that are chemically bonded together to form a single molecule of a particular element or compound. For instance, in the case of elements, if a molecule consists of only one atom, it is monatomic (like Helium, He). If it consists of two atoms, it is diatomic (like Oxygen, O₂). Molecules made of three atoms are triatomic (like Ozone, O₃), and so on. For compounds, atomicity is the total count of all atoms of different elements present in one molecule. For example, a molecule of water (H₂O) has an atomicity of three (two hydrogen atoms and one oxygen atom).
1-Mark Questions (MCQ)
Calculate the % relative abundance of B -10 and B -11, if its average atomic mass is 10.804 amu.
Let the percentage abundance of B-10 be x and B-11 be 100 - x. Average atomic mass = [10.01294x + 11.009305(100 - x)]/100 = 10.804. Solving, x = 20.636%. Therefore B-10 = 20.636% and B-11 = 79.364%.
Ch 8Periodic Classification of Elements
5-Mark Questions
The electronic configuration of metal A is 2,8,18,1.
The metal A is copper (Cu). When copper is exposed to air and moisture, it forms a green layer of basic copper carbonate: 2Cu + O2 + CO2 + H2O -> CuCO3.Cu(OH)2 So, B is basic copper carbonate. With concentrated sulphuric acid, copper forms copper sulphate, sulphur dioxide and water: Cu + 2H2SO4 -> CuSO4 + SO2 + 2H2O So, C is copper sulphate (CuSO4) and D is sulphur dioxide (SO2).
Metal A belongs to period 3 and group 13. A in red hot condition reacts with steam to form B. A with strong alkali forms C. Find A,B and C with reactions
A is aluminium (Al), because it belongs to period 3 and group 13. In red hot condition, aluminium reacts with steam to form aluminium oxide: 2Al + 3H2O -> Al2O3 + 3H2 So, B is aluminium oxide (Al2O3). With strong alkali, aluminium forms sodium meta aluminate: 2Al + 2NaOH + 2H2O -> 2NaAlO2 + 3H2 So, C is sodium meta aluminate (NaAlO2).
2-Mark Questions
A is a reddish brown metal, which combines with O2 at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A,B and C with reaction.
A is copper (Cu), the reddish brown metal. At a temperature below 1370 K, copper forms black copper(II) oxide: 2Cu + O2 -> 2CuO So, B is copper(II) oxide (CuO). At a temperature above 1370 K, copper forms red copper(I) oxide: 4Cu + O2 -> 2Cu2O So, C is copper(I) oxide (Cu2O).
A is a silvery white metal. A combines with O2 to form B at 800oC, the alloy of A is used in making the aircraft. Find A and B
A is aluminium (Al), a silvery white metal. At about 800°C it combines with oxygen to form aluminium oxide: 4Al + 3O2 -> 2Al2O3 So, B is aluminium oxide (Al2O3). Aluminium alloys are used in making aircraft because they are light and strong.
What is rust? Give the equation for formation of rust.
When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface. This compound is known as rust and the phenomenon is known as rusting. 4Fe + 3O2 + xH2O -> 2Fe2O3.xH2O (rust)
1-Mark Questions (MCQ)
a) Identify the bond between H and F in HF molecule.
a) The bond between H and F in the HF molecule is a polar covalent bond. b) This identification is based on the significant difference in electronegativity between hydrogen and fluorine. Fluorine is highly electronegative, while hydrogen is less electronegative. This unequal sharing of electrons creates a partial positive charge on the hydrogen atom and a partial negative charge on the fluorine atom, resulting in a polar bond. c) Electronegativity generally increases from left to right across a period in the periodic table due to an increasing nuclear charge and a decrease in atomic radius. …
Ch 9Solutions
5-Mark Questions
Write notes on i) saturated solution ii) unsaturated solution
(i) A saturated solution is a solution in which the maximum amount of solute has been dissolved in a given amount of solvent at a specific temperature. At this point, the rate of dissolution of solute equals the rate of crystallization of solute, and no more solute can be dissolved under these conditions. An example is 36 grams of sodium chloride dissolved in 100 grams of water at 25°C, which forms a saturated solution. (ii) An unsaturated solution is a solution that contains less solute than the maximum amount that can be dissolved in the solvent at a given temperature. …
Write notes on various factors affecting solubility.
There are three main factors which govern solubility: nature of the solute and solvent, temperature and pressure. Nature of solute and solvent: Solubility follows "like dissolves like". Polar compounds dissolve in polar solvents, for example common salt dissolves in water. Non-polar compounds dissolve in non-polar solvents, for example sulphur dissolves in carbon disulphide. Temperature: Generally, the solubility of a solid in a liquid increases with increase in temperature. In endothermic dissolution, solubility increases with temperature; in exothermic dissolution, it decreases. …
2-Mark Questions
Define the term: Solution
A solution is defined as a homogeneous mixture of two or more substances. In a homogeneous mixture, the composition and properties are uniform throughout the mixture. This means that the solute particles are completely dissolved in the solvent, and they cannot be distinguished by the naked eye or even under a microscope. Examples include salt dissolved in water or sugar dissolved in water.
What is mean by binary solution
A binary solution is a solution that consists of only two components: one solute and one solvent. The solute is the substance that is dissolved, and the solvent is the substance in which the solute is dissolved. For instance, when sodium chloride (solute) is dissolved in water (solvent), it forms a binary solution. Most common solutions encountered are binary in nature.
Give an example each i) gas in liquid ii) solid in liquid iii) solid in solid iv) gas in gas
(i) Gas in liquid: Carbon dioxide dissolved in water, as seen in carbonated beverages like soda water, is an example of a gas dissolved in a liquid. (ii) Solid in liquid: Sodium chloride (common salt) dissolved in water is a classic example of a solid dissolved in a liquid. (iii) Solid in solid: Alloys are solid solutions where one solid is dissolved in another. For example, gold with a small amount of copper dissolved in it forms an alloy, which is a solid in solid solution. …
1-Mark Questions (MCQ)
Will the cool drinks give more fizz at top of the hills or at the foot? Explain
Cool drinks will fizz more at the top of the hill. At higher altitude, pressure is lower, so the solubility of carbon dioxide in the drink decreases and more CO2 escapes as bubbles.
Ch 10Carbon and its Compounds
5-Mark Questions
Classify the following compounds based on the pattern of carbon chain and give their structural formula: (i) Propane (ii) Benzene (iii) Cyclobutane (iv) Furan
(i) Propane is an acyclic saturated alkane. It is a straight-chain hydrocarbon with the molecular formula C3H8. Its structural formula is CH3-CH2-CH3, where three carbon atoms are linked by single bonds and each carbon atom is bonded to the required number of hydrogen atoms to satisfy its valency. (ii) Benzene is a cyclic aromatic hydrocarbon with the molecular formula C6H6. Its structure consists of a six-membered ring of carbon atoms with alternating single and double bonds, exhibiting resonance. (iii) Cyclobutane is an alicyclic saturated hydrocarbon with the molecular formula C4H8. …
How do detergents cause water pollution? Suggest remedial measures to prevent this pollution?
Some detergents cause water pollution because they contain branched hydrocarbon chains which are not easily biodegradable. These persistent detergents remain in water bodies, leading to the formation of persistent foam and a significant reduction in water quality. Furthermore, certain detergents contain phosphates, which act as nutrients for aquatic plants. An excessive amount of phosphates can lead to eutrophication, characterized by rapid growth of algae (algal blooms). …
2-Mark Questions
Name the simplest ketone and give its structural formula.
The simplest ketone is acetone, which is also known by its IUPAC name propanone. It is the smallest molecule that contains a carbonyl group (C=O) bonded to two alkyl groups. In the case of acetone, these alkyl groups are both methyl groups (-CH3). Its structural formula is CH3COCH3, clearly showing the central carbonyl group flanked by two methyl groups. It is a volatile, flammable liquid with a characteristic pungent odor.
How is ethanoic acid prepared from ethanol? Give the chemical equation.
Ethanoic acid is prepared from ethanol by oxidation using oxidising agents such as acidified potassium dichromate or alkaline potassium permanganate on heating. CH3CH2OH + 2[O] -> CH3COOH + H2O
The molecular formula of an alcohol is C4H10O. The locant number of its -OH group is 2.
(i) Given that the molecular formula of the alcohol is C4H10O and the locant number of its -OH group is 2, we can deduce its structural formula. The parent chain has four carbon atoms (butane). The -OH group is attached to the second carbon atom. Therefore, the structural formula is CH3-CH(OH)-CH2-CH3. (ii) Following the IUPAC nomenclature rules, the parent chain is butane, and the functional group is an alcohol (-OH) located at position 2. Thus, the IUPAC name of this compound is butan-2-ol. …
1-Mark Questions (MCQ)
An organic compound ‘A’ is widely used as a preservative and has the molecular formula C2H4O2. This compound reacts with ethanol to form a sweet smelling compound ‘B’.
(i) Compound A is ethanoic acid (acetic acid), CH3COOH. (ii) It reacts with ethanol in the presence of concentrated H2SO4 to form the sweet-smelling ester ethyl ethanoate, B: CH3COOH + C2H5OH --conc. H2SO4-> CH3COOC2H5 + H2O (iii) The process is esterification.
Ch 11Types of Chemical Reactions
5-Mark Questions
Differentiate reversible and irreversible reactions
Reversible reaction: i. It proceeds in both forward and backward directions under suitable conditions. ii. Forward and backward reactions take place simultaneously. iii. It can attain dynamic equilibrium. iv. Reactants and products coexist; reactants are not completely converted into products. Example: N2(g) + 3H2(g) ⇌ 2NH3(g). Irreversible reaction: i. It proceeds essentially in one direction under the given conditions. ii. Equilibrium is not attained. iii. Reactants can be completely converted into products. Example: 2Mg(s) + O2(g) -> 2MgO(s).
Explain the types of double displacement reactions with examples.
Types of double displacement reactions: (i) Precipitation reaction: Two aqueous ionic solutions react to form an insoluble salt, called a precipitate. Pb(NO3)2(aq) + 2KI(aq) -> PbI2(s) + 2KNO3(aq) (ii) Neutralization reaction: An acid reacts with a base to form salt and water. HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l) (iii) Gas-evolution reaction: The reaction produces a gas that escapes. Na2CO3(aq) + 2HCl(aq) -> 2NaCl(aq) + H2O(l) + CO2(g)
2-Mark Questions
When an aqueous solution of potassium chloride is added to an aqueous solution of silver nitrate, a white precipitate is formed. Give the chemical equation of this reaction.
KCl(aq) + AgNO3(aq) -> KNO3(aq) + AgCl(s)↓
Why does the reaction rate of a reaction increase on raising the temperature?
The reaction rate of a chemical reaction increases when the temperature is raised primarily because of an increase in the kinetic energy of the reactant particles. At higher temperatures, particles move faster and collide more frequently. More importantly, a larger proportion of these collisions possess sufficient energy, known as the activation energy, to overcome the energy barrier and lead to a successful reaction. Therefore, both the frequency of collisions and the fraction of effective collisions increase with temperature, resulting in an overall acceleration of the reaction rate.
Define combination reaction. Give one example for an exothermic combination reaction.
A combination reaction is a reaction in which two or more reactants combine to form a single product. It is also called a synthesis reaction or composition reaction. Example: On burning magnesium in air, it combines with oxygen to form magnesium oxide: 2Mg(s) + O2(g) -> 2MgO(s)
1-Mark Questions (MCQ)
The hydroxide ion concentration of a solution is 1 \times 10-11M. What is the pH of the solution?
[OH-] = 1 x 10^-11 M pOH = -log10[OH-] = 11 pH + pOH = 14 pH = 14 - 11 = 3
Ch 12Structural Organisation of Animals
5-Mark Questions
List out the parasitic adaptations in leech.
Leeches exhibit several remarkable adaptations for their parasitic lifestyle of blood-feeding on vertebrates. Their muscular pharynx acts as a powerful suction pump to ingest blood. Both the anterior and posterior suckers are highly developed, enabling the leech to firmly attach to the host's body. For feeding, they possess three sharp jaws that create a Y-shaped, painless wound, minimizing detection. The salivary glands secrete hirudin, an anticoagulant that prevents blood coagulation, thus ensuring a steady supply of blood. …
How is the circulatory system designed in leech to compensate the heart structure ?
In leeches, the circulatory system is primarily a haemocoelic system, meaning it is integrated with the coelomic cavity, and there isn't a distinct, highly developed heart as seen in many other animals. Circulation is managed by four longitudinal channels that are filled with a blood-like coelomic fluid containing haemoglobin. One of these channels is located dorsally, another ventrally, and two are situated laterally. The two lateral channels are particularly important as they are contractile and possess valves, functioning analogously to hearts. …
2-Mark Questions
Give the common name of the Hirudinar via granulosa.
Indian cattle leech is the common name of Hirudinaria granulosa.
How does leech respire?
Leeches respire through their body surface, which is their skin. They possess a cutaneous respiratory system. The skin of the leech is thin and permeable, allowing for the diffusion of dissolved oxygen from the surrounding water into the leech's body and the diffusion of carbon dioxide out of the body. This process is efficient in aquatic environments where oxygen is readily available in the water.
Write the dental formula of rabbit.
The dental formula of rabbit is: I 2/1, C 0/0, PM 3/2, M 3/3 Total number of teeth = 28.
1-Mark Questions (MCQ)
How is the digestive system of rabbit suited for herbivorous mode of feeding?
The digestive system of a rabbit is highly adapted for its herbivorous diet, which primarily consists of fibrous plant material. Key adaptations include specialized dentition and a significantly enlarged caecum. Rabbits possess heterodont dentition, meaning they have different types of teeth suited for their diet, although they lack canine teeth. Their incisors are prominent for gnawing, followed by a gap called the diastema, which facilitates chewing and manipulation of food. The large, well-developed caecum is a crucial component where microbial fermentation occurs. …
Ch 13Transportation in Plants and Circulation in Animals
5-Mark Questions
What causes the opening and closing of guard cells of stomata during transpiration?
The opening and closing of stomata, pores on the surface of leaves that regulate gas exchange and transpiration, are primarily controlled by the turgidity of specialized cells called guard cells. During daylight hours, when photosynthesis is active, guard cells absorb water from surrounding epidermal cells through osmosis. This influx of water increases their turgor pressure, causing them to swell and become more curved. This curvature pulls the stomatal pore open, facilitating the uptake of carbon dioxide for photosynthesis and the release of oxygen. …
Trace the pathway followed by water molecules from the time it enters a plant root to the time it escapes into the atmosphere from a leaf.
Water absorption begins when water enters the root hairs from the soil through osmosis, driven by a difference in water potential. From the root hairs, water moves across the root cortex towards the xylem. This movement can occur via two pathways: the apoplast pathway, through the cell walls and intercellular spaces, and the symplast pathway, through the cytoplasm of cells connected by plasmodesmata. As water reaches the endodermis, the Casparian strip, a waxy layer in the cell walls, blocks the apoplast pathway, forcing water to enter the symplast. …
2-Mark Questions
Name two layered protective covering of human heart.
The human heart is enclosed within a protective double-layered sac known as the pericardium. The outer layer is the fibrous pericardium, a tough, inelastic sac that anchors the heart and prevents overfilling. Inside this lies the serous pericardium, which is further divided into two sub-layers. The parietal layer of the serous pericardium lines the inner surface of the fibrous pericardium, while the visceral layer, also called the epicardium, is directly adhered to the surface of the heart muscle. …
What is the shape of RBC in human blood?
Biconcave / disc shaped.
Why is the colour of the blood red ?
The characteristic red color of blood is primarily due to the presence of a protein called hemoglobin, which is found within red blood cells (erythrocytes). Hemoglobin is a complex molecule containing iron, and it is this iron atom that binds with oxygen in the lungs. When oxygen binds to hemoglobin, it forms oxyhemoglobin, which has a bright red color. In the tissues, where oxygen is released for cellular respiration, hemoglobin becomes deoxygenated, forming deoxyhemoglobin, which has a darker, purplish-red hue. …
1-Mark Questions (MCQ)
Transpiration is a necessary evil in plants. Explain.
Transpiration, the process of water vapor loss from a plant's aerial parts, is often described as a 'necessary evil' because it is essential for plant survival and function, yet it also poses a risk of dehydration. It is necessary because it drives the ascent of sap, enabling the transport of water and dissolved mineral nutrients from the roots to the leaves, which is vital for photosynthesis and growth. Transpiration also plays a role in cooling the plant surface, preventing overheating, and helps maintain turgor pressure in cells, supporting leaf expansion and plant rigidity. …
Ch 14Plant Anatomy and Plant Physiology
5-Mark Questions
Write a short note on mesophyll.
(i) The tissue present between the upper and lower epidermis of a dicot leaf is called mesophyll. (ii) It is differentiated into Palisade parenchyma and Spongy parenchyma. Palisade parenchyma : (i) It is found just below the upper epidermis. The cells are elongated. (ii) These cells have more number of chloroplasts. The cells do not have intercellular spaces and they take part in photosynthesis. Spongy parenchyma : (i) It is found below the palisade parenchyma tissue. (ii) Cells are almost spherical or oval and are irregularly arranged. (iii) Cells have intercellular spaces. …
Why should the light dependent reaction occur before the light independent reaction?
(i) Light dependent reaction of photosynthesis refers to the light reaction / Hill reaction. This reaction occurs in the presence of light in the grana of chloroplast. (ii) During this process photosynthetic pigments absorb the light energy, and convert it into chemical energy ATP and NADPH2. (iii) The Light Independent reaction refers to the Dark reaction of photosynthesis or the biosynthetic pathway which occurs in stroma of chloroplast. (iv) During this reaction CO2, is reduced into carbohydrates with the help of light generated ATP and NADPH2. …
2-Mark Questions
What is collateral vascular bundle?
Collateral vascular bundle is one type of conjoint vascular bundle in which Xylem lies towards the centre and phloem lies towards the periphery. Eg : Dicot stem.
Where does the carbon that is used in photosynthesis come from?
The carbon that is used in photosynthesis comes from carbon dioxide in the air.
What is the common step in aerobic and anaerobic pathway?
Glycolysis is the common step in aerobic and anaerobic pathway.
1-Mark Questions (MCQ)
Where do the light dependent reaction and the Calvin cycle occur in the chloroplast?
(i) The light dependent reaction refers to the light reaction of photosynthesis or Hill reaction and occurs in the grana of chloroplast. (ii) The Calvin cycle occurs in the stroma of chloroplast. ---
Ch 15Nervous System
5-Mark Questions
With a neat labelled diagram explain the structure of a neuron.
A neuron typically consists of three basic parts: Cyton, Dendrites and Axon. (i) Cyton: (a) Cyton is also called cell body or perikaryon. It has a central nucleus with abundant cytoplasm called neuroplasm. (b) The cytoplasm has large granular body called Nissl’s granules and the other cell organelles like mitochondria, ribosomes, lysosomes, and endoplasmic recticulum. (c) Neurons do not have the ability to divide. (ii) Dendrites : (a) These are the numerous branched cytoplasmic processes that project from the surface of the cell body. They conduct nerve impulses towards the cyton. …
Illustrate the structure and functions of brain.
A human brain is formed of three main parts: (a) forebrain (b) midbrain and (c) hindbrain. Forebrain : The forebrain is formed of cerebrum and diencephalon. The latter consists of dorsal thalamus and ventral hypothalamus. Cerebrum : (i) It is the largest portion forming nearly two-third of the brain. The cerebrum is longitudinally divided into two halves called cerebral hemispheres by a deep cleft which are interconnected by thick band of nerve fibres called corpus callosum. (ii) The outer portion of each cerebral hemisphere is formed of grey matter and is called cerebral cortex. …
2-Mark Questions
Define stimulus.
‘Stimulus’ refers to the changes in the environmental condition, that are detected by receptors present in the body. Relevant changes in the activities of organisms to a particular stimuli are called their reactions or responses.
Name the parts of the hind brain.
It is formed of three parts cerebellum, pons and medulla oblongata.
What are the structures involved in the protection of brain?
The brain, the central control organ of the nervous system, is exceptionally well-protected by a multi-layered system. The outermost and most robust protective structure is the skull, also known as the cranium, a bony case that encases and shields the brain from physical trauma. Beneath the skull lie the meninges, a set of three protective membranes: the dura mater (outermost), the arachnoid mater (middle), and the pia mater (innermost). These membranes provide an additional layer of cushioning and support. …
1-Mark Questions (MCQ)
‘A’ is a cylindrical structure that begins from the lower end of medulla and extend downwards. It is enclosed in bony cage ‘B’ and covered by membranes ‘C’. As many as ‘D’ pairs of nerves arise from the structure ‘A’. (i) What is A? (ii) Name (a) bony cage ‘B’ and (b) membranes ‘C’ (iii) How much is D?
(i) A – Spinal cord. (ii)(a) B – Vertebral column (b) C – Meninges. (iii) D – 31 pairs of spinal nerves.
Ch 16Plant and Animal Hormones
5-Mark Questions
What are the hormones secreted by posterior lobe of the pituitary gland? Mention the tissues on which they exert their effect.
The hormones secreted by the posterior lobe of the pituitary gland are (a) Vasopressin : In kidney tubules it increases reabsorption of water. It reduces loss of water through urine and hence the name antidiuretic hormone. (b) Oxytocin helps in the contraction of the smooth muscles of uterus at the time of child birth and milk ejection from the mammary gland after child birth.
Which hormone requires iodine for its formation? What will happen if intake of iodine in our diet is low?
The hormone thyroxine, secreted by the thyroid gland, requires iodine as a crucial component for its synthesis. If the intake of iodine in our diet is insufficient, the thyroid gland cannot produce adequate amounts of thyroxine. This deficiency leads to a condition known as hypothyroidism. Hypothyroidism can manifest in several diseases, including Simple Goitre, where the thyroid gland enlarges in an attempt to compensate for the lack of iodine; Cretinism, which results from severe iodine deficiency during fetal development or infancy, leading to stunted physical and mental growth; and Myxoede …
2-Mark Questions
Which hormone promotes the production of male flowers in Cucurbits?
Gibberellin.
Write the name of a synthetic auxin.
2,4 D (2, 4 Dichlorophenoxy Acetic acid).
Which hormone induces parthenocarpy in tomatoes?
Auxin (e.g., NAA — naphthalene acetic acid).
1-Mark Questions (MCQ)
Susan’s father feels very tired and frequently urinates. After clinical diagnosis he was advised to take an injection daily to maintain his blood glucose level. What would be the possible cause for this? Suggest preventive measures.
Susan's father is likely suffering from diabetes mellitus, a condition characterized by persistently high blood glucose levels. This can occur due to insufficient production or utilization of insulin, a hormone produced by the beta cells of the pancreas. The fact that he requires daily insulin injections suggests he has insulin-dependent diabetes, also known as Type 1 diabetes, where the pancreatic beta cells may have been destroyed or are not functioning properly. …
Ch 17Reproduction in Plants and Animals
5-Mark Questions
How does developing embryo gets its nourishment inside the mother's body?
(i) The placenta is a disc shaped structure attached to the uterine wall and is a temporary association between the developing embryo and maternal tissues. (ii) It allows the exchange of food materials, diffusion of oxygen, excretion of nitrogenous wastes and elimination of carbon dioxide. (iii) A cord containing blood vessels that connects the placenta with the foetus is called the umbilical cord.
With a neat labelled diagram describe the parts of a typical angiospermic ovule.
(i) The main part of the ovule is the nucellus which is enclosed by two integuments leaving an opening called as micropyle. (ii) The ovule is attached to the ovary wall by a stalk known as funiculus. Chalaza is the basal part. (iii) The embryo sac contains seven cells and eight nuclei located within the nucellus. (iv) Three cells at the micropylar end form the egg apparatus and the three cells at the chalaza end are the antipodal cells. (v) The remaining two nuclei are called polar nuclei found in the centre. …
2-Mark Questions
If one pollen grain produces two male gametes, how many pollen grains are needed to fertilize 10 ovules?
10 pollen grains.
In which part of the flower germination of pollen grains takes place?
The germination of pollen grains, a crucial step in sexual reproduction in flowering plants, takes place on the stigma. The stigma is the receptive tip of the carpel, or of several carpels fused together, in the gynoecium of a flower. It is typically sticky or feathery to effectively trap pollen grains that land on it. Once a compatible pollen grain lands on the stigma, it absorbs moisture and nutrients, germinates, and grows a pollen tube down through the style to reach the ovary, where fertilization occurs.
Name two organisms which reproduces through budding.
Budding is a form of asexual reproduction where a new organism develops from an outgrowth or bud due to cell division at one particular site. This bud, when it detaches from the parent organism, grows into a new independent organism. Two common examples of organisms that reproduce through budding are yeast, a single-celled fungus, and Hydra, a small freshwater invertebrate belonging to the phylum Cnidaria. In yeast, a small bud forms on the parent cell, grows, and eventually separates. …
1-Mark Questions (MCQ)
Read the following passage and answer the questions that follow
(a) Menarche — the first menstruation. Typical onset about 11–15 years (commonly 11–13 years but varies). (b) Napkin hygiene measures: use clean sanitary pads or tampons; change pads every 4–6 hours (or more often if needed); wash external genital area with mild soap and water and dry; wash hands before and after changing pads; wrap used pads in paper/plastic and dispose in bin or use napkin incinerator — do not flush; do not reuse disposable pads; store pads hygienically. (c) Yes. Rahini was correct — such advertisements raise awareness about menstrual hygiene and safe products.
Ch 18Genetics
5-Mark Questions
Why is euploidy considered to be advantageous to both plants and animals?
Euploidy (having complete sets of chromosomes) can be advantageous because it often increases cell and organ size and vigour. In plants, polyploid euploids commonly produce larger flowers and fruits, higher yield and useful traits (e.g., seedless triploids). In animals euploidy effects vary; some polyploids show desirable traits but many polyploid animals are inviable or sterile.
A pure tall plant (TT) is crossed with pure dwarf plant (tt), what would be the F1 and F2 generations? Explain.
Crosses involving inheritance of only one pair of contrasting characters are called monohybrid cross. Cross between pure tall (TT) plant and Pure dwarf (tt) plant Parental Generation : Pure breeding Tall and dwarf plants are crossed (TT x tt). F1 Generation : Monohybrids are heterozygous tall. F2 Generation : Selfing of the F1 monohybrids takes place. Tall and dwarf plants are obtained in the ratio of 3:1 which is the phenotypic ratio. Genotypically plants are of three types as shown above and therefore genotypic ratio is 1:2:1.
2-Mark Questions
What is a cross in which inheritance of two pairs of contrasting characters are studied?
Dihybrid cross.
Name the conditions when both the alleles are identical?
Homozygous condition.
A garden pea plant produces axial white flowers. Another of the same species produced terminal violet flowers. Identify the dominant trait?
Position: Axial is dominant over terminal. Colour: Violet (purple) is dominant over white.
1-Mark Questions (MCQ)
Under which conditions does the law of independent assortment hold good and why?
The law of independent assortment holds when the genes for the two traits are on different (non‑homologous) chromosomes or are far apart on the same chromosome (not linked), each trait is controlled by a pair of alleles that segregate during gamete formation, and there is no interaction or linkage between the genes.
Ch 19Origin and Evolution of Life
5-Mark Questions
The degenerated wing of a kiwi is an acquired character. Why is it an acquired character?
(i) When there is a change in the environment, the animals respond to the change. (ii) They develop adaptive structures. The characters developed by the animals during their life time, in response to the environmental changes are called acquired characters. (iii) Lamarck’s use and disuse theory states that if an organ is used constantly, the organ develops well and gets strengthened. When an organ is not used for a long time, it gradually degenerates. …
Define Ethnobotany and write its importance.
(i) Ethnobotany is the study of a region’s plants and their practical uses through the traditional knowledge of the local culture of people^ (ii) The term Ethnobotany was coined by J. W. Harshberger in 1895 to include the study of plants used by the primitive and aboriginal people. Importance of Ethnobotany : (i) It provides traditional uses of plant. (ii) It gives information about certain unknown and known useful plants. (iii) The ethnomedicinal data will serve as a useful source of information for the chemists, pharmacologists and practitioners of herbal medicine. …
2-Mark Questions
A human hand, a front leg of a cat, a front flipper of a whale and a bat’s wing look dissimilar and adapted for different functions. What is the name given to these organs?
Homologous organs.
Which organism is considered to be the fossil bird?
Archaeopteryx.
What is the study of fossils called?
Palaeontology.
1-Mark Questions (MCQ)
Octopus, cockroach and frog all have eyes. Can we group these animals together to establish a common evolutionary origin. Justify your answer.
No. They cannot be grouped solely on presence of eyes. Correct classification: octopus — phylum Mollusca (Cephalopoda); cockroach — phylum Arthropoda (Insecta); frog — phylum Chordata (Amphibia).
Ch 20Breeding and Biotechnology
5-Mark Questions
State the importance of biofertiliser.
Importance of Biofertilizers : The term biofertilizer denotes all nutrient inputs of biological origin for plant growth Eg: Artificial inoculation of rice with cyanobacteria to increase soil fertility. Significance : (i) They are ecofriendly. (ii) They do not cause pollution like artificial fertilizers. (iii) Help to Safeguard natural resources. (iv) They are cheaper and economical.
How are stem cells useful in regenerative process?
(i) Sometimes cells, tissues and organs in the body may be permanently damaged or lost due to genetic condition or disease or injury. (ii) In such situations stem cells are used for the treatment of diseases which is called stem-cell therapy. (iii) In treating neurodegenerative disorders like Parkinsv./s disease and Alzheimer’s disease neuronal stem cells can be used to replace the damaged or lost neurons.
2-Mark Questions
Give the name of wheat variety having higher dietary fibre and protein.
Atlas 66 is a protein rich wheat variety.
Semi-dwarf varieties were introduced in rice. This was made possible by the presence of dwarfing gene in rice. Name this dwarfing gene.
The dwarfing gene was got from a dwarf variety of rice from China, named Dee-geo-woo-gen (DGWG).
Define genetic engineering.
Genetic engineering is the manipulation and transfer of genes from one organism into another to create a new DNA called as recombinant DNA (rDNA).
1-Mark Questions (MCQ)
‘P’ is a gene required for the synthesis of vitamin A. It is integrated with genome of ‘Q’ to produce genetically modified plant ‘R’.
P = gene(s) for provitamin A (beta‑carotene biosynthesis; e.g., psy and crtI). Q = the crop plant whose genome is modified (example: rice). R = the genetically modified plant (Golden Rice) that produces beta‑carotene (provitamin A) in edible tissues.
Ch 21Health and Diseases
5-Mark Questions
AIDS 5. CHD 6. NIDDM
Cancer cells have a large nucleus, often with an increased nucleus-to-cytoplasm ratio. Normal cells have a comparatively small, regular nucleus.
Differentiate between Type-1 and Type-2 diabetes mellitus
Factors : Type I - Insulin dependent diabetes mellitus (IDDM) : Type II - Non-insulin dependent diabetes mellitus (NIDDM) Prevalence : 10 - 20% : 80 - 90% Age of Onset : Juvenile onset (< 20 years) : Maturity onset (> 30 years) Body weight : Normal or Underweight : Obese Defect : Insulin deficiency due to destruction of (\beta -cells : Target cells do not respond to insulin Treatment : Insulin administration is necessary : Can be controlled by diet, exercise and medicine.
2-Mark Questions
IDDM 2. HIV 3. BMI
Hypertension: persistent high blood pressure. Hypercholesterolemia: abnormally high cholesterol level in blood. Glycosuria: presence of glucose in urine. Hyperglycemia: high blood glucose level.
Chemotherapy: Chemicals :: Radiation therapy: __________
Radiation.
Hypertension: Hypercholesterolemia: Glycosuria: Hyperglycemia
Hypertension: persistent high blood pressure. Hypercholesterolemia: abnormally high cholesterol level in blood. Glycosuria: presence of glucose in urine. Hyperglycemia: high blood glucose level.
1-Mark Questions (MCQ)
What precautions can be taken for preventing heart diseases ?
Diet: reduce total calories if overweight; limit saturated fats and trans fats and dietary cholesterol; include moderate polyunsaturated and monounsaturated fats; reduce salt (sodium); eat more fruits, vegetables, whole grains and dietary fiber. Lifestyle: regular physical activity (daily exercise/walking), maintain healthy weight. Avoid smoking and excessive alcohol. Regular medical checkups to monitor blood pressure and blood cholesterol.
Ch 22Environmental Management
5-Mark Questions
Why fossil fuels are to be conserved?
Fossil fuels refer to coal and petroleum. (i) The formation of these fossil fuels is a very slow process and takes very long period of time for renewal. (ii) They are available in limited amounts in nature. Therefore the coal and petroleum reserves can get exhausted if we use them at a rapid rate. Thus they must be conserved.
What are the advantages of using biogas?
(i) It burns without smoke and therefore causes less pollution. (ii) An excellent way to get rid of organic wastes like bio-waste and sewage material. (iii) Left over slurry is good manure rich in nitrogen and phosphorus. (iv) It is safe and convenient to use. (v) It can reduce the amount of greenhouse gases emitted.
2-Mark Questions
What will happen if trees are cut down?
Cutting down of trees gives rise to ecological problems like floods, drought, soil erosion, loss of wildlife, extinction of species, imbalance of biogeochemical cycles, alteration of climatic conditions and desertification.
What would happen if the habitat of wild animals is disturbed?
The animal will not be able to find food, shelter or live with its community. Such animals tend to migrate into residential areas, fields etc., affecting human life.
What are the agents of soil erosion?
Agents of soil erosion are high velocity of wind, air currents, flowing water, landslide, human activities (deforestation, farming and mining) and overgrazing by cattle.
1-Mark Questions (MCQ)
List any three activities based on 3R approach to conserve natural resources.
(i) Reduce use of natural resources. E.g: coal. (ii) Reuse the waste whenever possible. Example water from kitchens can be used for growing plants. (iii) Recycle materials wherever possible. Example (a) Use of treated sewage water for gardening. (b) Bio wastes to be made into compost. ---
Ch 23Visual Communication
2-Mark Questions
What is Scratch?
Scratch is a visual programming language used to create animations, cartoons and games easily.
Write a short note on editor and its main parts.
The Scratch editor has three main parts: Stage, Sprite and Script editor. The script editor contains the script area, block menu and block palette.
What is Stage?
Stage is the background area that appears when we open the Scratch window. It is usually white, and the background colour can be changed.
Frequently asked questions
- Define inertia. Give its classification.
- Inertia is the inherent property of an object that resists any change in its state of rest or uniform motion along a straight line, unless acted upon by an external unbalanced force. This means an object at rest will stay at rest, and an object in motion will continue in motion with the same velocity, unless a net force intervenes. Inertia is directly proportional to the mass of the object; a more massive object has more inertia. …
- Differentiate mass and weight.
- Mass is the amount of matter in a body. It is a scalar quantity, its SI unit is kilogram (kg), and it remains the same everywhere. Weight is the gravitational force acting on a body. It is a vector quantity, its SI unit is newton (N), and it is given by W = mg. Weight changes from place to place because g changes.
- Classify the types of force based on their application.
- Forces can be classified into two main types based on whether they require physical contact between the interacting bodies or not. The first type is contact force, which is a force that acts only when two bodies are in direct physical contact. Examples of contact forces include frictional force, which opposes motion between surfaces in contact; normal force, which is perpendicular to the surface of contact; and muscular force, which is applied by the muscles of living beings. …
- If a 5 N and a 15 N forces are acting opposite to one another. Find the resultant force and the direction of action of the resultant force
- Let the forces be 5 N and 15 N acting in opposite directions. Resultant magnitude = |15 N - 5 N| = 10 N. Direction: toward the 15 N force (the larger force).
These important questions are selected from the Samacheer Kalvi Class 10 Science textbook book-back exercises to help you revise the most useful questions. Mark weightage (5/2/1) follows the usual exam pattern and may vary by exam — always check your latest syllabus and question pattern. Open each chapter for the complete set of questions and answers.