Physics – scope and excitement; nature of physical laws; Physics, technology and society
Physics Class 11 Notes Chapter 1
Physics is the study of matter, basic principles and laws of nature along with their manifestations. The study of physics is mainly involved in the explanations of the diverse phenomena of its concepts.
Physical World
The physical world is referred to as the complexity in nature and solving its own complexities will give us new insights into this physical world. It is referred to as the analysis of nature conducted in order to understand how the world around us performs.
What are the Fundamental Forces of nature?
In this diverse world, the fundamental forces which govern the phenomena occurring in it are:
- Gravitational Force – it is a universal force that exists which is of mutual attraction between any two objects by virtue of their masses.
- Electromagnetic Force – is the force between charged particles. If charges are in a state of rest, it is given by Coulumb’s law whereas when they are in motion, they generate a magnetic field, hence the name electromagnetic forces as they are inseparable. They also act over a large distance as seen in the case of gravitational forces without the intervention of any medium
- Strong Nuclear Force – in a nucleus it binds protons and neutrons. It is the strongest of all the fundamental forces and is charge-independent acting between proton-proton, proton-neutron, or neutron-neutron
- Weak Nuclear Force – observed only in some nuclear processes. Example – β-decay of a nucleus. It is not as weak as the gravitational force but weaker than electromagnetic and strong nuclear force
What are the laws of conservation in nature?
The conservation laws in physics are very important when it comes to understanding the subject. The laws are:
- Laws of Conservation of Mass
- Laws of Conservation of Energy
- Laws of Conservation of Momentum
- Laws of Conservation of Charge etc
Scientific
Method
Several inter-related steps are involved in scientific method. Some of the most
significant steps are as follows:
- The systematic observations
- Reasoning
- Mathematical modeling
- Theoretical prediction
Physics in Relation to Other
Sciences
Physics is a very significant branch of science which plays a crucial role in
understanding the developments pertaining to the other branches of science such
as Chemistry, Biology etc.
(i) Physics in relation to Mathematics. Study of physical variables
led to the idea of differentiation, integration and differential equation.
Meaningful interpretation of Mathematics becomes Physics.
(ii) Physics in relation to Chemistry. The concept of X-ray
diffraction and radioactivity has helped to distinguish between the various
solids and to modify the periodic table.
Understanding the bonding and the chemical structure of substances is easy with
the help of the concept of interactions between various particles.
(iii) Physics in relation to Astronomy. Optical telescopes of
reflecting and refracting type enabled man to explore the space around.
Discoveries like radio telescopes have revolutionised the study of Astronomy.
(iv) Physics in relation to Biology. The conceptual study of
pressure and its measurement has helped us to know blood pressure and hence the
functioning of heart. Invention of X-rays developed the field of diagnosis.
Electron and optical microscopic designs have revolutionised the study of
medical science.
(v) Physics in relation to
Meteorology. The discoveries
regarding the study of pressure variations help us to forecast the weather.
Various other inventions of physics have opened new vistas of study in the
field of sciences and social sciences.
Physics in Relation to
Technology and Society
Advancement in physics has led to new technologies and vice-versa. Sometimes
technology gives rise to new dimension of physics; at other times physics
generates new technology. In fact, the technological development is closely
related to the application of science and physics in particular. Physics has a
dominant influence on society. It has helped the human being to develop its
ideas. Development of digital communication systems, rapid mass transport
system, lasers making bloodless surgeries, etc., has made human life easy and
pleasant.
Scope and Excitement of
Physics
The scope of Physics is very broad and covers a wide range of magnitude of
physical quantities such as length, mass, time, energy, etc.
It deals with the macroscopic world like galaxies and universe as well as
microscopic world like nucleus of an atom and fundamental particles like
electrons, protons, neutrons etc.
Immense excitement is involved in the study of physics since it explains every
naturally occuring phenomena with a set of rules, so that clear understanding
can be achieved. The challenge to carry out imaginative new experiments to
unlock the secrets of nature, to verify or refute theories, is really exciting.
Important Questions
- What do you think did Einstein mean when he said: “The most incomprehensible thing about the world is that it is comprehensible”?
- “Every great physical theory starts as a heresy and ends as a dogma”. Give some examples from the history of the science of the validity of this incisive remark
- Politics is the art of the possible”. Similarly, “Science is the art of the soluble”. Explain this aphorism on the nature and practice of science.
Objective Questions (MCQ)
- Electromagnetic force is –
- Attractive in nature
- Repulsive in nature
- Attractive as well as repulsive in nature
- None of these
- Which of the following force is not a fundamental force in nature?
- Gravitational force
- Electromagnetic force
- Strong nuclear force
- Tension
- Strongest force in nature –
- Gravitational force
- Weak force
- Electromagnetic force
- Nuclear force