Physics is a branch of Science which is devoted to the study of nature.
The method involved is as follows:
1. Taking a large number of systematic observations through controlled experiments.
2. Studying these observations and looking for logical behaviour
3. Mathematical Modeling.
4. Prediction based on the model.
5. Fine tuning the model.
Physics consists of two parts (a) Classical Physics and (b) Modern Physics
(a) Classical Physics consists of the following sub-topics:-
1. Mechanics deals with the study of general system of particles, rigid bodies, deformable bodies, liquids etc, propulsion of rockets, propagation of waves etc.
2. Thermodynamics deals with changes in temperature, internal energy and entropy of the system. Modes of transfer of heat, the efficiency of heat engines and
refrigerators.
3. Electrodynamics deals with the study of electric and magnetic phenomena associated with charged particles and magnetic materials.
4. Optics deals with the study of phenomena associated with light and optical instruments.
(b) Modern Physics deals with Quantum Theory. Quantum Theory is the physics of particles of atomic size.
FUNDAMENTAL FORCES IN NATURE
The fundamental forces of nature are Gravitational Force, Electromagnetic Force, Strong Nuclear Force and Weak Nuclear Force. Their nature is discussed below.
(a) Gravitational Force: The gravitational force is a force of mutual attraction between any two objects by virtue of their masses. Itâs important properties are :
1. They are universally attractive forces.
2. They are the weakest forces in nature.
3. They operate over long distances.
4. Gravitational Forces obey inverse square law
5. They are central forces as they act along the line joining the centre of two bodies.
6. Are conservative forces.
(b) Electromagnetic Force:Â Â Forces between charged particles. Itâs important properties are :
1. The forces may be attractive or repulsive.
2. Electromagnetic Forces are governed by Coulombâs Law.
3. Obey Inverse-square Law
4. They are 1036 times stronger than the gravitational forces.
5. Operate over moderate distances.
6. Electromagnetic Forces are both conservative and central in nature.
(c) Strong Nuclear Force: The forces that bind the neutrons and protons together in a nucleus are called strong nuclear forces. Itâs important properties are :
1. Strongest forces in nature.
2. Short ranged force up to 10-14 meters.
3. Nuclear force does not depend on the charge of the nucleon.
4. Do not obey the inverse square law.
5. Basically attractive forces which are non-central or non-conservative
forces.
(d) Weak Nuclear Force:  The force is seen during beta decay. The weak nuclear forces are the forces of interaction between elementary particles of short live times. Itâs important properties are is that itâs a weak force but is 1025 times that of the gravitational force.
The notes on âChapter 1: Physical Worldâ is here
Let me know anything more you would like. Do comment on the postâŚit helps.
Physicall world notes
I want to revised this chapter and plz give me notes
Click… “here” to download the notes. Good Luck
Helped me for my project
Gr8
very brief and to the point …. thnx a lot
Thanks
its good but you must add some morethings.
I will update shortly.. Thanks for your interest.
i want to get physics class 11 notes help me and upload notes please…..i am w8ng
Good
Thank you
I want some help in my study by which i comple my chapte clearly….
You can ask your doubts… I will try to help you.
u missed some topics in this chapter…nature of physical laws,towards unification of forces,etc…is that impotant portions???
Yes… But as the idea was only to introduce 4 types of forces in nature, the unification of forces was kept aside for another day. đ
Only 2 page. Is it sufficient for understand the whole chapter
No… Its to get u interested in the topic.
i want to study the physics chapter
Yar pleas give some intrusting knowlege
help me out plz!!
I’m asked to write out a seminar report on the chapter ‘physical world’ from ncert XIth physics text book….pls help do me in making notes….
Tomorrow is my paper and I want to revise the notes
All the best for the paper.
Tomorrow is my paper and I want to revise the notes
So please let me revise the notes
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