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Practice Class 9 Science MCQ Questions with Answers based on the latest NCERT syllabus. Learn about the properties of matter, functions of stomata, displacement, isotopes, and friction with original concept-based explanations, exam-focused notes, and NCERT-aligned solutions for CBSE and State Board students.
Do You Know
Chapter Information
Subject: Science
Class: 9
Chapters Covered:
- Matter in Our Surroundings
- The Fundamental Unit of Life
- Motion
- Structure of the Atom
- Force and Laws of Motion
Question Type: Multiple Choice Questions (MCQs)
Difficulty Level: Easy to Moderate
Based On: Latest NCERT Syllabus
Introduction
Science helps us understand the properties of matter, the structure of living organisms, and the laws governing motion and forces. Concepts such as matter, stomata, displacement, isotopes, and friction are fundamental topics in Class 9 Science and are frequently tested in school and competitive examinations. This practice set strengthens conceptual understanding through original NCERT-based explanations.
What You Will Learn
✔ Properties of matter
✔ Functions of stomata
✔ Scalar and vector quantities
✔ Isotopes
✔ Friction and its effects
Why This Topic Is Important?
These topics form the foundation of Physics, Chemistry, and Biology. A clear understanding of these concepts improves problem-solving skills and prepares students for CBSE, State Board, Olympiad, and scholarship examinations.
Exam Relevance
These questions are useful for:
✔ CBSE Exams
✔ State Board Exams
✔ School Tests
✔ Unit Tests
✔ Half-Yearly Exams
✔ Annual Exams
✔ Olympiad Preparation
✔ Scholarship Examinations
Quiz Explanations
Q1. Matter has:
A) Colour
B) Mass & Volume
C) Shape
D) Taste
Answer
Mass & Volume
Concept
Matter is anything that has mass and occupies space.
Explanation
Every substance classified as matter has mass and occupies space (volume). While some materials may have colour, shape, or taste, these properties are not common to all forms of matter. Mass and volume are the fundamental characteristics of matter.
Exam Focus
Remember:
Matter = Has Mass + Occupies Space (Volume)
Matter is defined by two fundamental characteristics: it must have mass (the amount of substance) and occupy volume (space). While properties like shape, color, or taste can vary or change, mass and volume are present in all forms of matter.
Q2. Stomata help in:
A) Gas exchange
B) Growth
C) Transport
D) Photosynthesis
Answer
Gas exchange
Concept
Stomata are tiny pores found mainly on the surface of leaves.
Explanation
Stomata regulate the exchange of gases between the plant and the atmosphere. They allow carbon dioxide to enter for photosynthesis and release oxygen and water vapour. They also play an important role in transpiration.
Exam Focus
Remember:
Stomata → Gas Exchange + Transpiration
Stomata are microscopic pores found on the surface of leaves. Their main role is to facilitate gas exchange by allowing Carbon Dioxide ( $$CO_2$$ ) to enter for photosynthesis and letting Oxygen ( $$O_2$$ ) and water vapor exit the plant.
Q3. Displacement is:
A) Vector
B) Scalar
C) Both
D) None
Answer
Vector
Concept
Physical quantities are classified as scalar or vector depending on whether direction is involved.
Explanation
Displacement is the shortest straight-line distance between the initial and final positions of an object and always includes both magnitude and direction. Therefore, displacement is a vector quantity.
Exam Focus
Remember:
- Distance → Scalar
- Displacement → Vector
Q4. Isotopes differ in:
A) Neutrons
B) Protons
C) Mass only
D) Electrons
Answer
Neutrons
Concept
Isotopes are atoms of the same element that have the same atomic number but different mass numbers.
Explanation
Isotopes contain the same number of protons but different numbers of neutrons. Because the neutron count changes, their mass numbers are different while their chemical properties remain nearly the same.
Exam Focus
Remember:
Isotopes → Same Protons, Different Neutrons
Displacement is a Vector quantity because it describes both “how far” an object has moved and “in which direction.” Unlike distance (which is scalar and only cares about the total path covered), displacement focuses on the straight-line change in position.
Q5. Friction:
A) Opposes motion
B) Increases speed
C) Helps motion
D) None
Answer
Opposes motion
Concept
Friction is a contact force that acts between two surfaces.
Explanation
Friction always acts in the direction opposite to motion or the tendency of motion. It slows down moving objects and prevents unnecessary slipping. Although friction is useful in many everyday activities, it also causes wear and tear and generates heat.
Exam Focus
Remember:
Friction → Opposes Relative Motion
Important Formulas & Concepts
1. Matter
Matter is anything that:
- Has mass
- Occupies space
2. Stomata
Functions:
- Gas exchange
- Transpiration
- Regulation of water loss
3. Scalar and Vector Quantities
Scalar Quantities
- Distance
- Speed
- Mass
- Time
Vector Quantities
- Displacement
- Velocity
- Force
- Acceleration
4. Isotopes
Characteristics:
- Same atomic number
- Same number of protons
- Different number of neutrons
- Different mass numbers
5. Friction
Advantages:
- Helps us walk
- Enables writing
- Allows vehicles to move
Disadvantages:
- Produces heat
- Causes wear and tear
- Reduces efficiency
Related Practice Questions
- Define matter and write its two basic properties.
- What are the functions of stomata?
- Differentiate between distance and displacement.
- What are isotopes? Give one example.
- State two advantages and two disadvantages of friction.
Mini Quiz Challenge
True or False
- Matter has mass and occupies space.
- Stomata help in gas exchange.
- Displacement is a scalar quantity.
- Isotopes have different numbers of neutrons.
- Friction acts opposite to motion.
Exam Tips
✔ Learn the difference between scalar and vector quantities.
✔ Remember the basic properties of matter.
✔ Revise the functions of stomata.
✔ Understand the definition of isotopes.
✔ Learn the advantages and disadvantages of friction.
Quick Revision Notes
✔ Matter has mass and occupies space.
✔ Stomata regulate gas exchange and transpiration.
✔ Displacement is a vector quantity.
✔ Isotopes differ in the number of neutrons.
✔ Friction opposes motion.
Common Mistakes Students Make
❌ Confusing mass with weight.
❌ Assuming stomata are only involved in photosynthesis.
❌ Mixing up distance and displacement.
❌ Thinking isotopes differ in the number of protons.
❌ Believing friction always has harmful effects.
Key Takeaways
- Matter is anything that has mass and occupies space.
- Stomata regulate gas exchange and transpiration in plants.
- Displacement is a vector quantity because it has magnitude and direction.
- Isotopes have the same number of protons but different numbers of neutrons.
- Friction opposes relative motion between two surfaces.
FAQs
1. What are the two basic properties of matter?
Matter has mass and occupies space (volume).
2. What is the main function of stomata?
Stomata mainly help in gas exchange and also regulate transpiration.
3. Is displacement a scalar or vector quantity?
Displacement is a vector quantity because it has both magnitude and direction.
4. How do isotopes differ from each other?
Isotopes differ in the number of neutrons, resulting in different mass numbers.
5. What is friction?
Friction is a contact force that opposes the relative motion between two surfaces in contact.
NCERT Reference
Book: NCERT Science Class 9
Chapters Covered:
- Chapter 1 – Matter in Our Surroundings
- Chapter 5 – The Fundamental Unit of Life
- Chapter 8 – Motion
- Chapter 4 – Structure of the Atom
- Chapter 9 – Force and Laws of Motion
Based On: Latest NCERT Curriculum (CBSE)
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