Chapter-1 Class-11
Physical World
By Kartik Dagur
1.
What is Science?
Answer: The knowledge which humans have gain through observations and experiments when organised systematically is called science.
2.
What is physics?
Answer: Physics is the branch of the science which is devoted to the study of nature and natural phenomenon.
Scope and excitement of Physics:
The scope of physics is microscopic physics, modern physics,
mechanics, thermodynamics, electrodynamics optics.
Physics in relation
to other Sciences:
-Physics in relation to chemistry.
- Physics in relation to biological
science.
- Physics in relation to astronomy.
- Physics in relation to other sciences
like biophysics, geology, aceanography.
- Physics in related to
society.
- Physics in related to
mathematics.
The development in
physics have a direct impact on society:
-Development of telephone,
telegraph, telex enable us to transmite message.
- Development
of radio, t.v, satellite for communication.
- Exploration
of the new Sources of energy.
-Advance in electrons, computers, leasures for the transport like truck,
bus, motor cycle etc.
Fundamental forces in
nature:
-Gravitational Force:
it is a attraction force between two bodies. It is directly proportional to
the product of mass of bodies and inversely proportional to the square of the
distance between bodies.
Therefore:
Properties of
gravitational force:
-it is a attractive force.
-it is weakest force in nature.
-it is operate over very long distance.
-it is obey inverse square law.
-it is conservative force. These are central force.
Weak nuclear force:
These are the forces of interaction between elementary
particles (electron, anti-nutrons etc) of short life terms.
Properties of weak
nuclear force:
-it is weak force and 10 to the power 25 times stronger then
gravitational forces.
-it is exist between elementary particles.
Electromagnetic
force:
It is the force between two point charges. According to
coulomb law the attractive or repulsive electromagnetic forces between two
point charges is directly proportional to the product of charges and inversely
proportional to the square of the distance between of them.
Therefore:
[EO = electrical permitivity of
free space].
Properties of
electromagnetic force:
-it is repulsive or attractive in nature.
-it is obey inverse square law.
-these are central forces.
-these are conservative forces.
-if the charged particle is in rest then the force is called
electrostatic force. If charged particle does not move the force is called
electromagnetic force.
-it is 10 to the power 36 times stronger than gravitational
force.
Strong nuclear force:
The force that hinds neutrons and protons together in a
nucleus is called strong nuclear force.
Properties of strong
nuclear force:
-it is 10 to the power 38 times stronger then gravitational
force.
-it has smallest range.
-do not obey inverse square law.
-it is attractive force.
-non- central force.
-non- conservative force.
Nature of physics
law:
Some physical remain constant in time these are called
conserved quantities. In the classic physical deal with the following
conservation of laws.
-law of conservation
of energy: the sum of the total energy of all kinds in the universe remains
constant. It can be transferred from one to another.
-law of conservation of
linear momentum: According to this law in the absence of an external force
system remains unchanged.
-law of conservation
of angular momentum: According to this law if the total external tarque
acting on the system is zero than angular momentum of the system remains
constant.
-law of conservation
of charge: According to this law chare are neither created nor destroyed
but transferred from one to another.
So friends or students these are notes for class 11 chapter 1. These
notes are very best for learning and easy language.
THANKYOU
No comments:
Post a Comment