Class 11 Physics Chapter 1 – Physical World: Notes + PYQs for CBSE, JEE & NEET
Introduction
Physics is not just a subject; it’s the study of nature and its laws. In this first chapter – Physical World, we explore what Physics is, its scope, its relationship with technology and society, and the fundamental forces of nature.
This blog includes:
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Easy-to-understand notes
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Previous year questions (PYQs) from CBSE, JEE, and NEET
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Key definitions and diagrams
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Perfect for 2025 exam prep!
Key Topics Covered in Physical World
1. What is Physics?
Physics is the study of fundamental laws of nature and their applications in the natural world.
2. Scope and Excitement of Physics
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Ranges from particles (~10⁻¹⁴ m) to galaxies (~10²⁶ m)
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Helps understand how nature works at every scale
3. Physics, Technology & Society
Physics has led to major innovations like:
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💡 Lasers, X-rays, MRI
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🛰️ Satellites, GPS, Nuclear energy
4. Fundamental Forces in Nature
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Gravitational Force
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Electromagnetic Force
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Strong Nuclear Force
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Weak Nuclear Force
5. Unification of Forces
Efforts to combine all fundamental forces into a single framework.
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Example: Electroweak Theory (Nobel Prize 1979)
6. Physics and Other Sciences
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Physics + Chemistry → Physical Chemistry
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Physics + Biology → Biophysics
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Physics + Astronomy → Astrophysics
Important Terms You Must Remember
• Physics – Study of laws of nature
• Unification – Combining different forces into one theory
• Reductionism – Explaining complex systems by simpler parts
• Fundamental Force – Basic interaction in nature
• Scope of Physics – Study of matter, energy, time, space
Previous Year CBSE Questions
Q1. Define physics. Mention any two
of its scopes. (2023) [2 Marks]
Answer:
Physics
is the branch of science concerned with the nature and properties of matter and energy.
Scope
of Physics:
1. Understanding
the behavior of the universe from microscopic particles to galaxies.
2. Applications in medical science (e.g., MRI, X-rays), engineering, and communication.
Q2. Name the four fundamental forces in nature. (2022) [1 Mark]
Answer:
The four fundamental forces are:
1. Gravitational
Force
2.
Electromagnetic Force
3.
Strong Nuclear Force
4. Weak Nuclear Force
Q3. Write two
examples showing the link between technology and physics. (2021) [2 Marks]
Answer:
1.
Development of MRI technology in medical imaging is
based on nuclear magnetic resonance (Physics).
2. Satellites and GPS systems function based on the laws of motion and gravitation.
Q4. Differentiate between
gravitational and electromagnetic force. (2020) [2 Marks]
Answer:
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Q5. What is unification in physics? Give one example. (2019) [2
Marks]
Answer:
Unification is the attempt to
explain all the fundamental forces and their interactions using a single
theoretical framework.
Example: Electroweak theory
unifies electromagnetic and weak nuclear forces.
JEE Previous Year Questions
Q1.Which of the following is NOT a fundamental force in nature? (2024)
(a)
Gravitational Force
(b)
Electromagnetic Force
(c)
Muscular Force
(d)
Strong Nuclear Force
Correct Answer: (c) Muscular
Force
Explanation: Muscular force is a contact force and is not
considered one of the four fundamental forces of nature.
Q2. Which force is responsible for the stability of the atomic
nucleus? (2023)
(a)
Gravitational Force
(b)
Electromagnetic Force
(c)
Weak Nuclear Force
(d)
Strong Nuclear Force
Correct
Answer: (d) Strong Nuclear Force
Explanation: Strong
nuclear force binds protons and neutrons inside the nucleus and is the
strongest known force in nature.
Q3. Match the following: (2022)
Group-A
Group-B
A. Gravitational Force 1.
Infinite range, always attractive |
B. Electromagnetic Force 2.
Infinite range, attractive/repulsive |
C. Strong Nuclear Force 3.
Shortest range, strongest force |
D. Weak Nuclear Force 4.
Short range, responsible for beta decay |
Correct Matching:
A → 1, B → 2, C → 3, D → 4
Explanation:
·
Gravitational: infinite range, weakest but
always attractive
·
EM: acts on charges, infinite range
·
Strong: short range (~10⁻¹⁵
m), binds nucleus
· Weak: responsible for beta decay in radioactivity
Q4. What is the nature of gravitational force? (2020)
(a)
Always repulsive
(b)
Always attractive
(c)
Sometimes attractive
(d)
None of these
Correct Answer: (b) Always
attractive
Explanation: Gravitational force between any two masses is
always attractive in nature, as stated by Newton’s Law of Gravitation.
NEET Previous Year Questions
Q1. Identify the strongest force in nature: (2023)
(a)
Gravitational Force
(b)
Electromagnetic Force
(c)
Weak Nuclear Force
(d)
Strong Nuclear Force
Correct Answer: (d) Strong
Nuclear Force
Explanation:
Strong nuclear force is responsible for binding protons and neutrons inside the
nucleus. It has the maximum strength
but a very short range (~10⁻¹⁵
m).
Q2. Which branch of physics is used in MRI
technology? (2022)
(a)
Mechanics
(b)
Optics
(c)
Nuclear Magnetic Resonance
(d)
Thermodynamics
Correct Answer: (c) Nuclear
Magnetic Resonance
Explanation:
MRI (Magnetic Resonance Imaging) uses the principle of nuclear magnetic resonance (NMR), a key concept in
modern physics and medical diagnostics.
Q3. Name the force responsible for
radioactive beta decay: (2021)
(a)
Gravitational Force
(b)
Electromagnetic Force
(c)
Strong Nuclear Force
(d)
Weak Nuclear Force
Correct Answer: (d) Weak
Nuclear Force
Explanation:
The weak nuclear force governs beta decay, which is a type of
radioactive decay involving the transformation of a neutron into a proton and
an electron (beta particle).
Q4. Match the following pairs: Physics Branch ↔ Application (2020)
Group-A Group-B
A. Mechanics 1.
Launching a Rocket
B. Optics 2.
Working of Microscope
C. Thermodynamics 3. Steam
Engine
D.
Electromagnetism 4.
Electric Bell
Correct Matching:
A → 1, B → 2, C → 3, D → 4
Explanation:
·
Mechanics
→ Deals with motion (Rocket)
·
Optics
→ Light behavior (Microscope)
·
Thermodynamics
→ Heat & work (Steam Engine)
· Electromagnetism → Electricity & magnetism (Electric Bell)
FAQs – Frequently Asked Questions
Question-1: What are the 4 fundamental forces in nature?
Answer: Gravitational, Electromagnetic, Strong Nuclear, Weak Nuclear
Question-2: Who is considered the father of modern physics?
Answer: Albert Einstein
Question-3: What is the scope of physics?
Answer: Study of matter, energy, and their interactions from microscopic to cosmic scales
Question-4: Is there any numerical in this chapter?
Answer: No numerical, but conceptual questions are important for boards
Summary
Physical World may seem like a theory-based chapter, but it lays the foundation for deeper concepts in physics. Questions from this chapter are direct, conceptual, and easy to score. Perfect for CBSE Board exams, NEET, and JEE theory sections.
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