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Practice Class 9 Science MCQ Questions with Answers based on the latest NCERT syllabus. Learn about fat digestion, neutron discovery, velocity, SI unit of work, and evaporation with detailed explanations, formulas, exam tips, and NCERT-based solutions for CBSE and State Board students.
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Chapter Information
Subject: Science
Class: 9
Topics Covered:
- The Fundamental Unit of Life
- Structure of the Atom
- Motion
- Work and Energy
- Matter in Our Surroundings
Question Type: Multiple Choice Questions (MCQs)
Difficulty Level: Easy to Moderate
Based On: Latest NCERT Syllabus
Introduction
Class 9 Science introduces students to important concepts from Biology, Chemistry, and Physics that form the foundation for higher classes. Topics such as digestion, atomic structure, motion, work, and changes in the state of matter are closely connected to everyday life and are frequently tested in school examinations. Practicing concept-based MCQs helps improve understanding, analytical thinking, and problem-solving skills.
What You Will Learn
✔ Digestion of fats in the human body
✔ Discovery of the neutron
✔ Difference between speed and velocity
✔ SI unit of work
✔ Cooling effect of evaporation
✔ Important NCERT concepts and formulas
Why This Topic Is Important?
These concepts explain many natural phenomena and scientific principles used in daily life. They are regularly asked in CBSE, State Board, Olympiads, NTSE, and other competitive examinations. A clear understanding of these topics also builds a strong foundation for Class 10 Science.
Exam Relevance
These questions are useful for:
✔ CBSE Exams
✔ State Board Exams
✔ School Tests
✔ Unit Tests
✔ Half-Yearly Exams
✔ Annual Exams
✔ Olympiads
✔ Scholarship Examinations
Q1. Fat is completely digested in the:
A) Mouth
B) Small intestine
C) Stomach
D) Large intestine
Answer
Small intestine
Concept Behind This Question
Most digestion, including the complete digestion of fats, takes place in the small intestine.
Step-by-Step Solution
Fat digestion begins after bile juice emulsifies fats into tiny droplets. Pancreatic and intestinal enzymes then break fats into simpler substances such as fatty acids and glycerol.
The mouth and stomach do not complete fat digestion, while the large intestine mainly absorbs water.
Therefore, the correct answer is: Small intestine.
Exam Tip
Remember:
Small intestine = Main site of digestion and absorption.
Q2. Neutron was discovered by:
A) Rutherford
B) Chadwick
C) Bohr
D) Dalton
Answer
James Chadwick
Concept Behind This Question
The discovery of the neutron completed the basic understanding of atomic structure.
Step-by-Step Solution
In 1932, British physicist James Chadwick discovered the neutron, a neutral particle present in the nucleus of an atom.
Other scientists made different contributions:
- Dalton proposed the atomic theory.
- Rutherford discovered the atomic nucleus.
- Bohr explained the arrangement of electrons in shells.
Therefore, the correct answer is: James Chadwick.
Exam Tip
Remember these discoveries:
- Electron → J.J. Thomson
- Proton → Ernest Rutherford
- Neutron → James Chadwick
Q3. Velocity includes:
A) Distance
B) Time
C) Speed
D) Direction
Answer
Direction
Useful Formula for This Question
$$\text{Velocity}=\frac{\text{Displacement}}{\text{Time}}$$
Concept Behind This Question
Velocity is a vector quantity because it has both magnitude and direction.
Step-by-Step Solution
Speed tells us how fast an object moves, whereas velocity tells us both how fast and in which direction it moves.
Without direction, the quantity is only speed.
Therefore, the correct answer is: Direction.
Exam Tip
Remember:
- Speed → Scalar quantity
- Velocity → Vector quantity
Q4. Unit of work:
A) Pascal
B) Watt
C) Newton
D) Joule
Answer
Joule
Useful Formula for This Question
$$\text{Work}=\text{Force}\times\text{Displacement}$$
$$W=F\times s$$
Concept Behind This Question
Work is done when a force causes an object to move through a certain distance.
Step-by-Step Solution
The SI unit of work is the Joule (J).
One joule of work is done when a force of 1 newton moves an object by 1 metre in the direction of the applied force.
$$1~J=1~N\times1~m$$
Therefore, the correct answer is: Joule.
Exam Tip
Do not confuse:
- Joule → Work and Energy
- Watt → Power
- Newton → Force
- Pascal → Pressure
Q5. Evaporation causes:
A) Melting
B) Cooling
C) Freezing
D) Heating
Answer
Cooling
Concept Behind This Question
Evaporation removes heat energy from the surroundings.
Step-by-Step Solution
During evaporation, the highest-energy liquid particles escape into the air as vapour.
To do this, they absorb heat from the surroundings, causing the remaining liquid and nearby surfaces to become cooler.
Examples include:
- Sweat cooling the body.
- Water in an earthen pot remaining cool.
Therefore, the correct answer is: Cooling.
Exam Tip
Evaporation is a surface phenomenon and always produces a cooling effect.
Important Formulas & Concepts
1. Velocity
$$\text{Velocity}=\frac{\text{Displacement}}{\text{Time}}$$
Velocity has magnitude and direction.
2. Speed
$$\text{Speed}=\frac{\text{Distance}}{\text{Time}}$$
Speed is a scalar quantity.
3. Work
$$W=F\times s$$
SI Unit:
Joule (J)
4. Fat Digestion
- Bile juice emulsifies fats.
- Fat digestion is completed in the small intestine.
5. Atomic Particles
- Electron → Negative charge
- Proton → Positive charge
- Neutron → No charge
6. Evaporation
Factors affecting evaporation:
- Higher temperature
- Larger surface area
- Faster wind speed
- Lower humidity
Evaporation always causes cooling.
Related Practice Questions
- Which organ secretes bile juice?
- Who discovered the electron?
- What is the SI unit of force?
- What is the difference between speed and velocity?
- Name two everyday examples of evaporation.
Mini Quiz Challenge
True or False
- Fat is completely digested in the stomach.
- James Chadwick discovered the neutron.
- Velocity includes direction.
- The SI unit of work is Joule.
- Evaporation produces a cooling effect.
Exam Tips
✔ Memorize the discoveries of major atomic particles.
✔ Learn the difference between speed and velocity.
✔ Remember SI units of physical quantities.
✔ Revise the stages of fat digestion.
✔ Understand why evaporation cools the surroundings.
Quick Revision Notes
✔ Fat digestion is completed in the small intestine.
✔ James Chadwick discovered the neutron.
✔ Velocity includes direction.
✔ Joule is the SI unit of work.
✔ Evaporation causes cooling.
✔ Work is measured in joules.
Common Mistakes Students Make
❌ Confusing speed with velocity.
❌ Writing Watt as the unit of work instead of power.
❌ Assuming fat digestion is completed in the stomach.
❌ Mixing up the discoveries of Rutherford, Bohr, and Chadwick.
❌ Thinking evaporation heats the surroundings.
Key Takeaways
- The small intestine is the main site of fat digestion.
- James Chadwick discovered the neutron in 1932.
- Velocity is a vector quantity because it includes direction.
- The SI unit of work is the joule.
- Evaporation absorbs heat and produces a cooling effect.
FAQs
1. Where is fat completely digested?
Fat is completely digested in the small intestine.
2. Who discovered the neutron?
James Chadwick discovered the neutron in 1932.
3. What makes velocity different from speed?
Velocity includes both speed and direction, while speed has only magnitude.
4. What is the SI unit of work?
The SI unit of work is the Joule (J).
5. Why does evaporation cause cooling?
Evaporation absorbs heat from the surroundings, reducing the temperature of the remaining liquid and nearby surfaces.
Conclusion
This Class 9 Science MCQ Practice Set covers key NCERT concepts from Biology, Chemistry, and Physics, including digestion, atomic structure, motion, work, and evaporation. Regular practice with detailed explanations and formulas helps students strengthen conceptual understanding, improve accuracy, and perform better in school examinations and competitive tests.
NCERT Reference
Book: NCERT Science Class 9
Relevant Chapters:
- Chapter 1: Matter in Our Surroundings
- Chapter 5: The Fundamental Unit of Life
- Chapter 4: Structure of the Atom
- Chapter 8: Motion
- Chapter 11: Work and Energy
Based On: Latest NCERT Curriculum (CBSE)
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