Q 1 – Which of the following statements is incorrect about particles of matter?
(a) Particles of matter are very small.
(b) Particles of matter have spaces between them.
(c) Particles of matter are not constantly moving.
(d) Particles of matter attract each other
(c) Particles of matter are not constantly moving.
Q 2 – Which of the following will show the property of diffusion most rapidly?
(a) Oxygen gas
(b) Salt solution
(c) Milk
(d) Ice cube
(a) Oxygen gas
Q 3 – A particle starts from rest with an acceleration of 4 m/s². After 5 seconds, the ratio of the distance covered in the 5th second to the total distance covered in 5 seconds is:
(a) 1 : 5
(b) 1 : 9
(c) 1 : 6
(d) 1 : 10
Q 4 – A car travels 30 km at a speed of 40 km/h and the next 30 km at 60 km/h. The average speed of the car is:
(a) 48 km/h
(b) 50 km/h
(c) 52 km/h
(d) 45 km/h
(a) 48 km/h
Q 5 – A body of mass 10 kg is moving with a uniform velocity of 2 m/s. The force required to keep the body moving with the same velocity on a frictionless surface is:
(a) 20 N
(b) 5 N
(c) 0 N
(d) 10 N
(c) 0 N
Q 6 – Two objects of masses m1 and m2 are placed at a distance r. If the distance between them is quadrupled, the masses m1 and m2 are made half and one third, the gravitational force becomes:
(a) F/2
(b) 8F/3
(c) 2F
d) 4F
Q 7 – Which of the following cell organelles is called the “Kitchen of the Cell”?
(a) Endoplasmic Reticulum
(b) Ribosome
(c) Mitochondria
(d) Chloroplasts
(d) Chloroplasts
Q 8 – Which of the following cell organelles is semi-autonomous (can divide on its own and has its own DNA)?
(a) Plastids
(b) None of these
(c) Mitochondria
(d) Both a and c
(d) Both a and c
Q 9 – Which of the following is not a function of the plasma membrane?
(a) Selective permeability
(b) Transport of materials
(c) Energy production
(d) Cell signaling
(c) Energy production
Q 10 – The thickening of cell walls at the corners is the characteristic of:
(a) Parenchyma
(b) Collenchyma
(c) Sclerenchyma
(d) Xylem
(b) Collenchyma
Q 11 – The main function of lenticels in woody stems is:
(a) Transport of food
(b) Transport of water
(c) Gaseous exchange
(d) Photosynthesis
(c) Gaseous exchange
Q 12 – Fill in the Blanks:
a) The temperature at which a solid changes into a liquid is called its __________.
b) Brass is an alloy of __________ and __________.
c) Gas particles have __________ intermolecular force of attraction.
d) The functional unit of life is __________.
e) The green pigment present in chloroplast is __________.
f) Phloem transports __________ from leaves to other parts of the plant.
g) The SI unit of acceleration is __________in terms of km and sec .
h) According to Newton’s Third Law, action and reaction forces are __________ in magnitude and __________ in direction.
i) The value of acceleration due to gravity (g) on Earth is approximately __________ m/s².
a) melting point
b) copper, zinc
c) negligible/very weak
d) cell
e) chlorophyll
f) food
g) km/s²
h) equal, opposite
i) 9.8 m/s²
(Choose: 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.)
Q 13 – Assertion (A): A passenger in a bus tends to fall forward when the bus suddenly stops.
Reason (R): The passenger’s body continues to move forward due to inertia of motion.
Both A and R are true, and R is the correct explanation of A.
Q 14 – Assertion (A): The weight of an object on the Moon is less than that on Earth.
Reason (R): The gravitational force of the Moon is weaker than that of the Earth.
Both A and R are true, and R is the correct explanation of A.
Q 15 – Assertion (A): Gases can be compressed easily.
Reason (R): The intermolecular space in gases is negligible.
A is true but R is false.
Q 16 – Assertion (A): Evaporation causes cooling.
Reason (R): The particles at the surface of a liquid gain energy from surroundings and escape.
Both A and R are true, and R is the correct explanation of A.
Q 17 – Assertion (A): Cell wall provides rigidity and protection to the plant cell.
Reason (R): Cell wall is mainly composed of cellulose.
Both A and R are true, and R is the correct explanation of A.
Q 18 – Assertion (A): Guard cells regulate the opening and closing of stomata.
Reason (R): Guard cells contain chloroplasts and can photosynthesize.
A is true but R is false.
Q 19 – Why does a gas exert pressure on the walls of a container? Explain in terms of particle theory.
A gas exerts pressure on the walls of a container because of the constant motion of its particles. According to the particle theory of matter:
- Gas particles are in continuous, random motion.
- These particles collide with each other and with the walls of the container.
- Each collision exerts a force on the walls.
The cumulative effect of countless collisions per unit area is observed as pressure.
Q 20 – Water at room temperature is a liquid, whereas iron at the same temperature is a solid. Why?
The difference is due to the strength of intermolecular (or interatomic) forces in the substances:
- Water: The molecules are held together by relatively weak hydrogen bonds, so at room temperature, the particles can move past each other, making water a liquid.
Iron: The atoms are held together by strong metallic bonds, which keep the atoms fixed in a rigid structure, so iron is a solid at room temperature.
Q 21 – Write four differences between prokaryotic and eukaryotic cells.
Feature | Prokaryotic Cell | Eukaryotic Cell |
Nucleus | No true nucleus; DNA is in nucleoid | True nucleus with nuclear membrane |
Membrane-bound organelles | Absent | Present (mitochondria, ER, etc.) |
Size | Usually smaller (1–10 μm) | Usually larger (10–100 μm) |
Cell division | Binary fission | Mitosis and meiosis |
Q 22 – Why are lysosomes called “suicidal bags” of the cell?
Lysosomes are called “suicidal bags” of the cell because they contain digestive enzymes that can break down cellular components.
- If a lysosome bursts inside a cell, these enzymes digest the cell’s own organelles and cytoplasm, leading to cell death.
Hence, they act like self-destruct mechanisms when necessary.
Q 23 – Why are meristematic tissues capable of division while permanent tissues are not?
Meristematic tissues are capable of division because:
- Their cells have thin cell walls, dense cytoplasm, and prominent nuclei, which allow them to actively divide.
- They are immature, undifferentiated cells that can form new cells for growth.
Permanent tissues, on the other hand:
- Have thickened and specialized cell walls.
- Cells are differentiated to perform specific functions.
- They lose the ability to divide once matured.
Q 24 – Explain why sclerenchyma cells are dead at maturity.
Sclerenchyma cells are dead at maturity because:
- Their primary function is mechanical support and strength.
- During maturation, they develop thick, lignified secondary cell walls, which harden the cells.
- The protoplasm degenerates after wall thickening, leaving the cell empty and non-living.
Q 25 – A body moving with uniform acceleration covers 40 m in the 5th second and 60 m in the 7th second. Find its initial velocity and acceleration.
Q 26 – The velocity–time graph of a body is a straight line passing through the origin and inclined at an angle with the time axis. Write the equations of motion that can be derived from this graph and explain briefly.
Q 27 – A bullet of mass 10 g moving with velocity 500 m/s strikes a wooden block of mass 2 kg and gets embedded in it. Calculate the velocity of the block after impact.
Q 28 – The mass of an object is constant everywhere but its weight changes from place to place. Why? Explain with reasoning.
Q 29 – Describe the structure and function of Golgi Appartus.
Structure:
- Made up of flattened, membrane-bound sacs called cisternae stacked one above the other.
- Vesicles are often seen at the edges of cisternae.
- Has two faces:
- Cis face: Receiving side (from ER)
- Trans face: Shipping side (towards plasma membrane or other organelles)
Functions:
- Modification of proteins and lipids received from the ER (e.g., glycosylation).
- Packaging and sorting of materials into vesicles.
- Formation of lysosomes.
- Secretion of substances outside the cell (exocytosis).
Plays a role in cell wall formation in plants.
Q 30 – Explain the structure and function of:
(a) Mitochondria
(b) Endoplasmic Reticulum (smooth and rough)
(a) Mitochondria
Structure:
- Oval or rod-shaped organelles with a double membrane.
- Outer membrane: Smooth.
- Inner membrane: Folded into cristae to increase surface area.
- Matrix: Inner space containing enzymes, DNA, and ribosomes.
Function:
- Powerhouse of the cell – produces ATP through cellular respiration.
- Involved in energy metabolism.
- Contains its own DNA and ribosomes (semi-autonomous).
(b) Endoplasmic Reticulum (ER)
Structure:
- Network of membrane-bound tubules and sacs called cisternae.
- Two types:
- Rough ER (RER) – has ribosomes on its surface.
- Smooth ER (SER) – lacks ribosomes.
Function:
- Rough ER:
- Synthesizes proteins for secretion, membranes, or lysosomes.
- Smooth ER:
- Synthesizes lipids and steroids.
- Detoxifies drugs and toxins.
- Stores calcium ions in muscle cells.
Q 31 – The nucleus is considered the control centre of the cell. Justify this statement by giving three reasons.
The nucleus is called the control centre of the cell because:
- It contains DNA, which stores genetic information that controls all cellular activities.
- It regulates cell growth, metabolism, and reproduction by controlling protein synthesis.
- It directs cell division and ensures the proper distribution of genetic material to daughter cells.
Q 32 – Explain how the structure of collenchyma and sclerenchyma helps in providing mechanical support to plants.
1. Collenchyma
Structure:
- Cells are elongated with unevenly thickened cell walls, especially at the corners.
- Walls are flexible and rich in cellulose and pectin.
Function in support:
- Provides flexible support to young stems and leaves.
- Allows the plant to bend without breaking, helping in growth and movement.
2. Sclerenchyma
Structure:
- Cells have thick, lignified secondary walls.
- Cells are usually dead at maturity and rigid.
Function in support:
- Provides rigid and strong support to mature parts of the plant.
- Helps the plant withstand mechanical stress and pressure.
Q 33 – Write any two differences between:
(a) Apical meristem and Lateral meristem
(b) Parenchyma and Collenchyma
(c) Meiosis and Mitosis
(d) Prokaryotic and Eukaryotic
(a) Apical meristem vs Lateral meristem
Feature | Apical meristem | Lateral meristem |
Location | Tips of roots and shoots | Along the sides of stems and roots |
Function | Increases length (primary growth) | Increases girth/diameter (secondary growth) |
(b) Parenchyma vs Collenchyma
Feature | Parenchyma | Collenchyma |
Cell wall | Thin, uniform | Unevenly thickened, mainly at corners |
Function | Storage, photosynthesis, basic metabolism | Provides flexible support to growing parts |
(c) Meiosis vs Mitosis
Feature | Meiosis | Mitosis |
Number of divisions | Two | One |
Chromosome number | Daughter cells are haploid | Daughter cells are diploid |
(d) Prokaryotic vs Eukaryotic
Feature | Prokaryotic | Eukaryotic |
Nucleus | No true nucleus (nucleoid) | True nucleus present |
Organelles | No membrane-bound organelles | Membrane-bound organelles present |
Q 34 – What is the effect of temperature and pressure on the solubility of gases and liquids.
- Solubility of gases
- Effect of Temperature:
- Solubility decreases with increase in temperature.
- Reason: Gas particles gain kinetic energy and escape from the solution more easily.
- Effect of Pressure:
- Solubility increases with increase in pressure (Henry’s Law).
- Reason: Higher pressure forces more gas molecules into the liquid.
2. Solubility of liquids
- Effect of Temperature:
- Solubility of most solids in liquids increases with temperature.
- Reason: Higher temperature increases molecular motion, allowing more solute to dissolve.
- Effect of Pressure:
- Solubility of liquids is not significantly affected by pressure.
Q 35 – A gun of mass 5 kg fires a bullet of mass 50 g with a velocity of 200 m/s. Calculate the recoil velocity of the gun. Which law of motion is used here?
Q 36 – State the universal law of gravitation and write its formula.
Universal Law of Gravitation:
Every particle in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Q 37 – Differentiate among true solutions, colloids and suspensions.
True Solution |
Colloidal Solution
| Suspensions |
True solutions are the mixtures in which the solute and the solvent mix properly in the liquid phase. | Colloidal solutions are the mixtures in which the solute is uniformly distributed in the solvent. | > 100 nm |
It is a homogenous solution. | It is a heterogeneous solution. | Heterogeneous, may be opaque |
The particles of true solution does not sediment. | The particles of a colloid might sediments sometimes. | Particles settle on standing |
It is a transparent solution. | It is a translucent solution. |
|
True solutions do show Tyndall effect. | Tyndall effect is shown by the colloids in their colloidal solution. | Yes (but less noticeable) |
Q 38 – Convert 27°C into Kelvin scale. Explain why Kelvin is called the SI unit of temperature and not Celsius.
Convert 27°C into Kelvin
K = °C + 273
K = 27 + 273 = 300 k
Why Kelvin is the SI unit of temperature
- Kelvin is an absolute scale starting from absolute zero (0 K), the temperature at which all molecular motion stops.
- SI units require a scale independent of arbitrary reference points; Celsius depends on the freezing/boiling points of water.
Kelvin is used in scientific calculations because it ensures proportionality in thermodynamic equations (e.g., ideal gas law).
Q 39 – Differentiate between evaporation and boiling in three points. Also, explain why evaporation causes cooling.
Evaporation | Boiling |
Evaporation is a normal process that occurs when the liquid form changes into the gaseous form; while causing an increase in the pressure or temperature. | Boiling is an unnatural process where the liquid gets heated up and vaporized due to continuous heating of the liquid. |
Evaporation usually occurs on the heated liquid’s surface. | Boiling usually occurs on the entire mass of the liquid that gets heated up. |
Bubbling effect is not visible in evaporation. | Bubbling effect is visible during the process of boiling. |
The process of evaporation is slow. | The process of boiling is much quicker. |