ADEPT YOURSELF
www.adeptyourself.com β’ Academic Excellence Series
CBSE CLASS IX β SCIENCE (CODE NO. 086)
SAMPLE QUESTION PAPER β SET 2 | ACADEMIC SESSION 2026β2027
General Instructions:
- The question paper comprises Five Sections: A, B, C, D and E. There are 39 questions in total.
- All questions are compulsory. However, an internal choice is provided in some questions.
- Section A consists of 20 objective type questions (Q1 to Q20) carrying 1 mark each. (Q1 to Q16 are MCQs, Q17 to Q20 are Assertion-Reasoning).
- Section B consists of 6 Very Short Answer type questions (Q21 to Q26) carrying 2 marks each.
- Section C consists of 7 Short Answer type questions (Q27 to Q33) carrying 3 marks each.
- Section D consists of 3 Long Answer type questions (Q34 to Q36) carrying 5 marks each.
- Section E consists of 3 Case-Based units of assessment (Q37 to Q39) carrying 4 marks each with sub-parts.
SECTION A β OBJECTIVE TYPE QUESTIONS (20 Marks)
Q1.
During summer, water kept in an earthen pot (matka) becomes cool because of the phenomenon of:
[1]
Q2.
Which of the following is a homogeneous mixture?
[1]
Q3.
Which cell organelle plays a crucial role in detoxifying many poisons and drugs in liver cells of vertebrates?
[1]
Q4.
The husk of a coconut is made up of which type of plant tissue?
[1]
Q5.
The slope of a velocity-time ($v$-$t$) graph gives:
[1]
Q6.
When a passenger jumps out of a moving bus, he falls forward due to:
[1]
Q7.
The weight of an object of mass $10\text{ kg}$ on the surface of the earth is: [Take $g = 9.8\text{ m/s}^2$]
[1]
Q8.
Which of the following contains the maximum number of molecules?
[1]
Q9.
Kitchen of the cell is:
[1]
Q10.
A passenger in a moving train tosses a coin which falls behind him. It means that the motion of the train is:
[1]
Q11.
Cathode rays in J.J. Thomson’s discharge tube experiment are streams of:
[1]
Q12.
Intestine absorbs the digested food materials. What type of epithelial cells are responsible for that?
[1]
Q13.
A girl is carrying a school bag of $3\text{ kg}$ mass on her back and moves $200\text{ m}$ on a level road. The work done against the gravitational force will be:
[1]
Q14.
SONAR is a device that uses which type of waves to measure the distance, direction, and speed of underwater objects?
[1]
Q15.
Which of the following is a fresh water fish variety used in composite fish culture in India?
[1]
Q16.
The atomic number of an element is equal to the number of:
[1]
Q17.
Assertion (A): Camphor disappears without leaving any residue when left open in air.
Reason (R): Camphor directly converts from solid state to gaseous state through sublimation without becoming liquid. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Reason (R): Camphor directly converts from solid state to gaseous state through sublimation without becoming liquid. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q18.
Assertion (A): Mitochondria are known as the powerhouses of the cell.
Reason (R): Mitochondria synthesize ATP (Adenosine Triphosphate) molecules through cellular respiration. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Reason (R): Mitochondria synthesize ATP (Adenosine Triphosphate) molecules through cellular respiration. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q19.
Assertion (A): A cricket player draws his hands backwards while catching a fast moving ball.
Reason (R): Increasing the time of the catch decreases the rate of change of momentum and exerts less force on the hands. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Reason (R): Increasing the time of the catch decreases the rate of change of momentum and exerts less force on the hands. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Q20.
Assertion (A): Sound cannot propagate through vacuum.
Reason (R): Sound is a mechanical wave that requires a material medium with elastic properties for propagation. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Reason (R): Sound is a mechanical wave that requires a material medium with elastic properties for propagation. [1]
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
SECTION B β VERY SHORT ANSWER QUESTIONS (12 Marks)
Q21.
Convert the following temperatures into the Celsius scale:
(a) $293\text{ K}$
(b) $470\text{ K}$ [2]
(a) $293\text{ K}$
(b) $470\text{ K}$ [2]
Q22.
Why is the plasma membrane called a selectively permeable membrane?
[2]
Q23.
An athlete completes one round of a circular track of diameter $200\text{ m}$ in $40\text{ s}$. What will be the distance covered and the displacement at the end of $2\text{ minutes }20\text{ s}$?
[2]
OR
A stone is dropped from a height and falls freely under gravity. What is the acceleration of the stone during free fall? What is its initial velocity?
Q24.
Why does an object float or sink when placed on the surface of water? Explain on the basis of relative density.
[2]
Q25.
Name two Italian honey bee varieties introduced in India and state one advantage of Italian bees over indigenous varieties.
[2]
Q26.
Calculate the formula unit mass of Zinc oxide ($\text{ZnO}$) and Potassium carbonate ($\text{K}_2\text{CO}_3$).
[Given: Atomic masses: $\text{Zn}=65\text{ u}$, $\text{K}=39\text{ u}$, $\text{C}=12\text{ u}$, $\text{O}=16\text{ u}$] [2]
[Given: Atomic masses: $\text{Zn}=65\text{ u}$, $\text{K}=39\text{ u}$, $\text{C}=12\text{ u}$, $\text{O}=16\text{ u}$] [2]
SECTION C β SHORT ANSWER QUESTIONS (21 Marks)
Q27.
Differentiate between a physical change and a chemical change on three fundamental parameters. Give one example of each.
[3]
Q28.
(a) Name the tissue that connects muscle to bone in animals.
(b) Name the tissue that connects two bones together.
(c) Which connective tissue has a fluid matrix called plasma? [3]
(b) Name the tissue that connects two bones together.
(c) Which connective tissue has a fluid matrix called plasma? [3]
Q29.
A motorcar of mass $1200\text{ kg}$ is moving along a straight line with a uniform velocity of $90\text{ km/h}$. Its velocity is slowed down to $18\text{ km/h}$ in $4\text{ s}$ by an unbalanced external force. Calculate:
(a) Acceleration of the car.
(b) The change in momentum.
(c) The magnitude of the force required. [3]
(i) The mass of one object is doubled?
(ii) The distance between them is tripled?
(a) Acceleration of the car.
(b) The change in momentum.
(c) The magnitude of the force required. [3]
OR
State Universal Law of Gravitation. What happens to the gravitational force between two objects if:
(i) The mass of one object is doubled?
(ii) The distance between them is tripled?
Q30.
(a) Define Power. What is the SI unit of power?
(b) A lamp consumes $1000\text{ J}$ of electrical energy in $10\text{ seconds}$. What is its power?
(c) Define 1 Watt of power. [3]
(b) A lamp consumes $1000\text{ J}$ of electrical energy in $10\text{ seconds}$. What is its power?
(c) Define 1 Watt of power. [3]
Q31.
(a) State the Law of Constant Proportions (Proust’s Law) with an illustrative example.
(b) In a sample of water ($\text{H}_2\text{O}$), the ratio of mass of hydrogen to oxygen is always $1 : 8$. What mass of oxygen gas would be required to react completely with $3\text{ g}$ of hydrogen gas? [3]
(b) In a sample of water ($\text{H}_2\text{O}$), the ratio of mass of hydrogen to oxygen is always $1 : 8$. What mass of oxygen gas would be required to react completely with $3\text{ g}$ of hydrogen gas? [3]
Q32.
Describe the three types of muscle tissues found in the human body (Striated, Smooth, Cardiac) based on shape, presence of striations, and nature of control.
[3]
Q33.
What is composite fish culture? Explain how surface feeders, column feeders, and bottom feeders are selected in a single fish pond without competition for food.
[3]
SECTION D β LONG ANSWER QUESTIONS (15 Marks)
Q34.
(a) State the rules given by Bohr and Bury for distribution of electrons into different shells of an atom.
(b) What is the maximum capacity of the K, L, M, and N shells?
(c) If $Z = 8$, write the electronic configuration of the element and determine its valency. [5]
(b) The nucleus of an atom contains 11 protons and 12 neutrons.
(i) What is the atomic number of this element?
(ii) What is its mass number?
(iii) Name the element and write its symbol with atomic number and mass number.
(c) Differentiate between Isobars and Isotopes with one example of each.
(b) What is the maximum capacity of the K, L, M, and N shells?
(c) If $Z = 8$, write the electronic configuration of the element and determine its valency. [5]
OR
(a) Define Atomic number and Mass number of an element.
(b) The nucleus of an atom contains 11 protons and 12 neutrons.
(i) What is the atomic number of this element?
(ii) What is its mass number?
(iii) Name the element and write its symbol with atomic number and mass number.
(c) Differentiate between Isobars and Isotopes with one example of each.
Q35.
(a) Draw a neat, labelled diagram of a Plant Cell (or describe any four of its major organelles).
(b) Mention four prominent structural differences between a Plant Cell and an Animal Cell.
(c) Why do plant cells tolerate greater changes in the surrounding hypotonic medium than animal cells without bursting? [5]
(i) Growth in length of the stem and root apex.
(ii) Increase in girth/diameter of the stem.
(iii) Growth of leaves and internodes.
(b) How does a meristematic tissue differ fundamentally from a permanent tissue?
(c) Explain the process of ‘differentiation’ in plant tissues.
(b) Mention four prominent structural differences between a Plant Cell and an Animal Cell.
(c) Why do plant cells tolerate greater changes in the surrounding hypotonic medium than animal cells without bursting? [5]
OR
(a) Name the meristematic tissue responsible for:
(i) Growth in length of the stem and root apex.
(ii) Increase in girth/diameter of the stem.
(iii) Growth of leaves and internodes.
(b) How does a meristematic tissue differ fundamentally from a permanent tissue?
(c) Explain the process of ‘differentiation’ in plant tissues.
Q36.
(a) Derive the three equations of motion graphically:
(i) $v = u + at$
(ii) $s = ut + \frac{1}{2}at^2$
(iii) $v^2 – u^2 = 2as$
(b) A car accelerates uniformly from $18\text{ km/h}$ to $36\text{ km/h}$ in $5\text{ s}$. Calculate the distance covered by the car in that time. [5]
(b) What are the various energy transformations that occur when:
(i) An archer releases an arrow from a stretched bow?
(ii) Coal is burned in a thermal power station to generate electricity?
(c) A body of mass $2\text{ kg}$ is thrown vertically upwards with an initial velocity of $20\text{ m/s}$. Find its potential energy at the highest point. [Take $g = 10\text{ m/s}^2$]
(i) $v = u + at$
(ii) $s = ut + \frac{1}{2}at^2$
(iii) $v^2 – u^2 = 2as$
(b) A car accelerates uniformly from $18\text{ km/h}$ to $36\text{ km/h}$ in $5\text{ s}$. Calculate the distance covered by the car in that time. [5]
OR
(a) Define Potential Energy. Derive the expression for the Gravitational Potential Energy ($E_p = mgh$) of an object of mass $m$ raised to height $h$.
(b) What are the various energy transformations that occur when:
(i) An archer releases an arrow from a stretched bow?
(ii) Coal is burned in a thermal power station to generate electricity?
(c) A body of mass $2\text{ kg}$ is thrown vertically upwards with an initial velocity of $20\text{ m/s}$. Find its potential energy at the highest point. [Take $g = 10\text{ m/s}^2$]
SECTION E β CASE-BASED INTEGRATED UNITS (12 Marks)
Q37. Read the following source carefully and answer the questions that follow:
[4](a) Name the two components that make up a colloidal solution. [1]
(b) Give an example of a colloidal system where liquid is dispersed in a gas. [1]
(c) State two properties of a suspension that distinguish it from a true solution. [2]
Solutions can be classified into true solutions, suspensions, and colloids based on particle size. A true solution is a homogeneous mixture where solute particles are smaller than $1\text{ nm}$ and do not settle down when left undisturbed. A suspension is a heterogeneous mixture in which solute particles are larger than $100\text{ nm}$ and remain suspended throughout the bulk of the medium. Colloids are intermediate mixtures where particle size ranges between $1\text{ nm}$ and $100\text{ nm}$, showing Tyndall scattering and Brownian movement.
(b) Give an example of a colloidal system where liquid is dispersed in a gas. [1]
(c) State two properties of a suspension that distinguish it from a true solution. [2]
OR
A solution contains $40\text{ g}$ of common salt in $320\text{ g}$ of water. Calculate the concentration of the solution in terms of mass-by-mass percentage. [2]
Q38. Read the following source carefully and answer the questions that follow:
[4](a) What type of wave is a sound wave in air? [1]
(b) Define one compression and one rarefaction. [1]
(c) State the relationship between frequency ($\nu$), wavelength ($\lambda$), and speed of sound ($v$). A sound wave has a frequency of $2\text{ kHz}$ and wavelength $35\text{ cm}$. How long will it take to travel $1.4\text{ km}$? [2]
Sound is produced due to vibrations of objects. Sound travels through a medium as longitudinal mechanical waves comprising alternating regions of high pressure (compressions) and low pressure (rarefactions). The speed of sound depends on the temperature, humidity, and elasticity of the transmitting medium. Sound waves cannot travel through vacuum. When sound waves encounter a hard boundary, they reflect back according to the laws of reflection, giving rise to echoes and reverberations.
(b) Define one compression and one rarefaction. [1]
(c) State the relationship between frequency ($\nu$), wavelength ($\lambda$), and speed of sound ($v$). A sound wave has a frequency of $2\text{ kHz}$ and wavelength $35\text{ cm}$. How long will it take to travel $1.4\text{ km}$? [2]
OR
What is reverberation? Suggest two methods used in auditorium halls to reduce excessive reverberation. [2]
Q39. Read the following source carefully and answer the questions that follow:
[4](a) Name the two scientific species of Indian cattle. [1]
(b) What are milch animals and draught animals? [1]
(c) What are the two main objectives of cross-breeding indigenous cattle with exotic breeds? [2]
Cattle farming is undertaken for two main purposes: milk production (milch animals) and draught labor for agricultural work like tilling, irrigation, and carting. Indian cattle belong to two species: Bos indicus (cows) and Bos bubalis (buffaloes). Exotic breeds like Jersey and Brown Swiss are selected for long lactation periods, whereas local breeds like Red Sindhi and Sahiwal show excellent disease resistance. Cross-breeding between exotic and indigenous breeds is practiced to combine both desirable qualities.
(b) What are milch animals and draught animals? [1]
(c) What are the two main objectives of cross-breeding indigenous cattle with exotic breeds? [2]
OR
Mention two basic food requirements of dairy cattle to maintain good health and high milk yield. [2]
CBSE CLASS IX SCIENCE (086) β SOLUTIONS & MARKING SCHEME β SET 2
SECTION A β ANSWERS
Q1. (d) Evaporation [1]
Q2. (b) Air [1]
Q3. (c) Smooth Endoplasmic Reticulum (SER) [1]
Q4. (a) Sclerenchyma tissue [1]
Q5. (c) Acceleration [1]
Q6. (b) Inertia of motion [1]
Q7. (c) $98\text{ N}$ [$W = mg = 10 \times 9.8 = 98\text{ N}$] [1]
Q8. (c) $1\text{ g of }\text{H}_2$ (Molar mass = 2 g/mol $\Rightarrow 0.5\text{ moles}$, maximum number of molecules) [1]
Q9. (b) Chloroplast [1]
Q10. (a) Accelerated [1]
Q11. (d) Electrons [1]
Q12. (b) Columnar epithelium [1]
Q13. (d) Zero (Angle between gravitational force and displacement is $90^\circ$, $W = F s \cos 90^\circ = 0$) [1]
Q14. (b) Ultrasonic sound waves [1]
Q15. (b) Catla [1]
Q16. (b) Protons in the nucleus [1]
Q17. (a) Both A and R are true and R is the correct explanation of A. [1]
Q18. (a) Both A and R are true and R is the correct explanation of A. [1]
Q19. (a) Both A and R are true and R is the correct explanation of A. [1]
Q20. (a) Both A and R are true and R is the correct explanation of A. [1]
SECTION B β ANSWERS
Q21.
- (a) $T(^\circ\text{C}) = 293 – 273 = \mathbf{20^\circ\text{C}}$
- (b) $T(^\circ\text{C}) = 470 – 273 = \mathbf{197^\circ\text{C}}$
Q22.
Plasma membrane permits the entry and exit of some select materials in and out of the cell while preventing the movement of other substances. Hence, it is called selectively permeable. [2]
Q23.
Radius $r = \frac{200}{2} = 100\text{ m}$. Time for 1 round = $40\text{ s}$.
Total time $t = 2\text{ min }20\text{ s} = 140\text{ s}$.
Number of rounds = $\frac{140}{40} = 3.5\text{ rounds}$.
(a) Distance $= 3.5 \times 2\pi r = 3.5 \times 2 \times \frac{22}{7} \times 100 = 3.5 \times 628.57 = \mathbf{2200\text{ m}}$.
(b) Displacement = Diameter of circular track = $\mathbf{200\text{ m}}$. [2]
OR
Total time $t = 2\text{ min }20\text{ s} = 140\text{ s}$.
Number of rounds = $\frac{140}{40} = 3.5\text{ rounds}$.
(a) Distance $= 3.5 \times 2\pi r = 3.5 \times 2 \times \frac{22}{7} \times 100 = 3.5 \times 628.57 = \mathbf{2200\text{ m}}$.
(b) Displacement = Diameter of circular track = $\mathbf{200\text{ m}}$. [2]
OR
- During free fall, the acceleration of the stone is constant and equal to the acceleration due to gravity ($g = 9.8\text{ m/s}^2$).
- Its initial velocity $u = 0$.
Q24.
- An object floats on water if its density is less than the density of water (buoyant force > weight of object).
- An object sinks in water if its density is greater than the density of water (buoyant force < weight of object).
Q25.
- Italian bee variety: Apis mellifera.
- Advantages: High honey collection capacity, sting less, breed very well, and stay in beehives for longer periods.
Q26.
- (a) $\text{ZnO} = 65 + 16 = \mathbf{81\text{ u}}$
- (b) $\text{K}_2\text{CO}_3 = 2 \times 39 + 12 + 3 \times 16 = 78 + 12 + 48 = \mathbf{138\text{ u}}$
SECTION C β ANSWERS
Q27.
- Physical Change: Reversible, no new chemical substance is formed, only physical state/properties change (e.g., melting of ice, cutting of trees).
- Chemical Change: Irreversible, new chemical substances with different chemical properties are formed, energy is absorbed or evolved (e.g., burning of paper, rusting of iron).
Q28.
- (a) Tendon connects muscle to bone.
- (b) Ligament connects bone to bone.
- (c) Blood (vascular connective tissue).
Q29.
Given: $m = 1200\text{ kg}$, $u = 90\text{ km/h} = 25\text{ m/s}$, $v = 18\text{ km/h} = 5\text{ m/s}$, $t = 4\text{ s}$.
(a) $a = \frac{v – u}{t} = \frac{5 – 25}{4} = \frac{-20}{4} = \mathbf{-5\text{ m/s}^2}$ (Retardation = $5\text{ m/s}^2$).
(b) Change in momentum $\Delta p = m(v – u) = 1200 \times (5 – 25) = 1200 \times (-20) = \mathbf{-24000\text{ kg}\cdot\text{m/s}}$.
(c) Force $F = m \times a = 1200 \times (-5) = -6000\text{ N}$. Magnitude = $\mathbf{6000\text{ N}}$. [3]
OR
(a) $a = \frac{v – u}{t} = \frac{5 – 25}{4} = \frac{-20}{4} = \mathbf{-5\text{ m/s}^2}$ (Retardation = $5\text{ m/s}^2$).
(b) Change in momentum $\Delta p = m(v – u) = 1200 \times (5 – 25) = 1200 \times (-20) = \mathbf{-24000\text{ kg}\cdot\text{m/s}}$.
(c) Force $F = m \times a = 1200 \times (-5) = -6000\text{ N}$. Magnitude = $\mathbf{6000\text{ N}}$. [3]
OR
- $F = G\frac{M \times m}{d^2}$.
- (i) If mass of one object is doubled ($M’ = 2M$), force becomes doubled ($F’ = 2F$).
- (ii) If distance is tripled ($d’ = 3d$), force becomes one-ninth ($F’ = \frac{F}{3^2} = \frac{F}{9}$).
Q30.
- (a) Power: Rate of doing work or rate of consumption of energy ($P = \frac{W}{t}$). SI unit is **Watt (W)**.
- (b) $P = \frac{W}{t} = \frac{1000\text{ J}}{10\text{ s}} = \mathbf{100\text{ W}}$.
- (c) **1 Watt** is the power of an appliance that consumes energy at the rate of 1 Joule per second ($1\text{ W} = 1\text{ J/s}$).
Q31.
- (a) Law of Constant Proportions: In a chemical substance, the elements are always present in definite proportions by mass regardless of the source or method of preparation.
- (b) In $\text{H}_2\text{O}$, $\text{Mass of H} : \text{Mass of O} = 1 : 8$.
For $1\text{ g}$ of Hydrogen, required Oxygen $= 8\text{ g}$.
For $3\text{ g}$ of Hydrogen, required Oxygen $= 3 \times 8 = \mathbf{24\text{ g}}$.
Q32.
- Striated (Skeletal) Muscle: Cylindrical, unbranched, multinucleate cells; show alternate light and dark bands (striations); voluntary in action.
- Smooth (Unstriated) Muscle: Spindle-shaped, uninucleate cells; no striations; involuntary in action (found in walls of stomach, intestine, blood vessels).
- Cardiac Muscle: Cylindrical, branched, uninucleate cells; show faint striations; involuntary, contract and relax rhythmically throughout life without fatigue.
Q33.
- Composite Fish Culture: A combination of 5 or 6 different fish species cultured together in a single fish pond so that they do not compete for food.
- Surface Feeders: Catlas feed on the surface of the pond.
- Column Feeders: Rohus feed in the middle zone of the pond.
- Bottom Feeders: Mrigals and Common Carps feed at the bottom; Grass Carps feed on aquatic weeds.
- This ensures complete and efficient utilization of all available food in the pond.
SECTION D β ANSWERS
Q34.
OR
- (a) Bohr-Bury Rules:
1. Maximum number of electrons in a shell is given by the formula $2n^2$ (where $n$ is shell number).
2. Maximum number of electrons that can be accommodated in the outermost valence shell is 8.
3. Electrons are not accommodated in a given shell unless the inner shells are completely filled. - (b) K shell ($n=1$): $2(1)^2 = 2$; L shell ($n=2$): $2(2)^2 = 8$; M shell ($n=3$): $2(3)^2 = 18$; N shell ($n=4$): $2(4)^2 = 32$.
- (c) For $Z = 8$ (Oxygen): Electronic configuration = $2, 6$ (K=2, L=6).
Valency $= 8 – 6 = \mathbf{2}$.
OR
- (a) Atomic Number ($Z$): Total number of protons present in the nucleus of an atom.
Mass Number ($A$): Total number of protons and neutrons (nucleons) present in the nucleus. - (b) Protons = 11, Neutrons = 12.
(i) Atomic number $Z = 11$.
(ii) Mass number $A = 11 + 12 = 23$.
(iii) Element is Sodium; Symbol: $\mathbf{^{23}_{11}\text{Na}}$. - (c) Isotopes: Same atomic number, different mass numbers (e.g., $^{35}_{17}\text{Cl}$ and $^{37}_{17}\text{Cl}$).
Isobars: Same mass number, different atomic numbers (e.g., $^{40}_{18}\text{Ar}$ and $^{40}_{20}\text{Ca}$).
Q35.
OR
- (a) Plant cell features: Large central vacuole, cell wall surrounding plasma membrane, plastids (chloroplasts), and prominent nucleus pushed to periphery.
- (b) Plant Cell vs Animal Cell:
1. Cell wall present in plant cell; absent in animal cell.
2. Chloroplasts/plastids present in plant cell; absent in animal cell.
3. Large central vacuole in plant cell; small, temporary vacuoles in animal cell.
4. Centrosome/centrioles absent in higher plant cells; present in animal cells. - (c) The rigid cellulose cell wall exerts an inward counter-pressure (wall pressure) against the turgor pressure of swelling cell contents, preventing plant cells from bursting in hypotonic solutions.
OR
- (a) (i) Apical meristem, (ii) Lateral meristem (Cambium), (iii) Intercalary meristem.
- (b) Meristematic vs Permanent: Meristematic cells continuously divide, are undifferentiated, have thin cellulose walls, dense cytoplasm, and lack vacuoles; Permanent cells lose the ability to divide, have specific specialized shapes, thick walls, and large vacuoles.
- (c) Differentiation: The process of taking up a permanent shape, size, structure, and specialized physiological function by meristematic cells to form permanent tissues.
Q36.
OR
- (a) Graphical Derivations: From $v$-$t$ graph with initial velocity $u$ and final velocity $v$ in time $t$:
(i) Slope $a = \frac{BC}{AC} = \frac{v – u}{t} \Rightarrow \mathbf{v = u + at}$.
(ii) Area under graph $s = \text{Area of rectangle } + \text{Area of triangle} = u \times t + \frac{1}{2} \times t \times (v – u) = ut + \frac{1}{2}at^2 \Rightarrow \mathbf{s = ut + \frac{1}{2}at^2}$.
(iii) $s = \text{Area of trapezium} = \frac{(u + v)}{2} \times t$. Substituting $t = \frac{v – u}{a} \Rightarrow s = \frac{v^2 – u^2}{2a} \Rightarrow \mathbf{v^2 – u^2 = 2as}$. - (b) $u = 18\text{ km/h} = 5\text{ m/s}$, $v = 36\text{ km/h} = 10\text{ m/s}$, $t = 5\text{ s}$.
$a = \frac{10 – 5}{5} = 1\text{ m/s}^2$.
$s = ut + \frac{1}{2}at^2 = 5(5) + \frac{1}{2}(1)(5)^2 = 25 + 12.5 = \mathbf{37.5\text{ m}}$.
OR
- (a) Potential Energy: Energy stored in an object by virtue of its position or configuration.
Derivation: Work done against gravity $W = \text{Force} \times \text{Displacement} = (mg) \times h = mgh$. Hence, $E_p = mgh$. - (b) (i) Stretched bow: Elastic potential energy $\rightarrow$ Kinetic energy of arrow.
(ii) Thermal power plant: Chemical energy of coal $\rightarrow$ Heat energy $\rightarrow$ Kinetic energy of steam turbine $\rightarrow$ Electrical energy. - (c) Given: $m = 2\text{ kg}$, $u = 20\text{ m/s}$, $g = 10\text{ m/s}^2$.
At highest point, $v = 0 \Rightarrow$ Maximum height $h = \frac{u^2}{2g} = \frac{400}{20} = 20\text{ m}$.
Potential energy $E_p = mgh = 2 \times 10 \times 20 = \mathbf{400\text{ J}}$ (or total initial $KE = \frac{1}{2} \times 2 \times 20^2 = 400\text{ J}$).
SECTION E β ANSWERS
Q37.
Total mass of solution $= 40 + 320 = 360\text{ g}$.
Mass $\% = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100 = \frac{40}{360} \times 100 = \frac{100}{9} = \mathbf{11.11\%}$. [2]
- (a) Dispersed phase (solute-like component) and Dispersion medium (solvent-like medium). [1]
- (b) Fog, clouds, or mist (Aerosol). [1]
- (c) Properties of suspension:
1. Heterogeneous mixture with visible large particles ($> 100\text{ nm}$).
2. Particles settle down when left undisturbed and can be separated by filtration. [2]
Total mass of solution $= 40 + 320 = 360\text{ g}$.
Mass $\% = \frac{\text{Mass of solute}}{\text{Mass of solution}} \times 100 = \frac{40}{360} \times 100 = \frac{100}{9} = \mathbf{11.11\%}$. [2]
Q38.
Reduction methods: Covering roofs and walls with sound-absorbing materials (compressed fiberboard, rough plaster) / Using heavy draperies and upholstered seats. [2]
- (a) Longitudinal mechanical wave. [1]
- (b) A compression is a region of high pressure/density where particles are crowded together; a rarefaction is a region of low pressure/density where particles are spread apart. [1]
- (c) Formula: $v = \nu \times \lambda$.
Given: $\nu = 2\text{ kHz} = 2000\text{ Hz}$, $\lambda = 35\text{ cm} = 0.35\text{ m}$.
Speed $v = 2000 \times 0.35 = 700\text{ m/s}$.
Time $t = \frac{\text{Distance}}{v} = \frac{1400\text{ m}}{700\text{ m/s}} = \mathbf{2.0\text{ seconds}}$. [2]
Reduction methods: Covering roofs and walls with sound-absorbing materials (compressed fiberboard, rough plaster) / Using heavy draperies and upholstered seats. [2]
Q39.
- (a) Bos indicus (cow) and Bos bubalis (buffalo). [1]
- (b) Milch animals: Milk-producing female dairy animals.
Draught animals: Animals used for agricultural labor (ploughing, tilling, cart pulling). [1] - (c) To combine the **long lactation period** of exotic breeds with the **strong disease resistance and climate adaptability** of indigenous breeds. [2]