Physics IX Notes Chapter 1 PHYSICAL QUANTITIES AND MEASUREMENT
Q.1 What is
physics? Also, describe its important branches?
PHYSICS :> The branch of science which deals
with the study of properties, energy and their mutual relationship is called
physics”
Some important branches of physics are given below
1.
Mechanics:-It deals with the motion of bodies
under the action of the force.
2.
Heat and thermodynamics:-It deals
with the study of nature, properties. and uses of heat energy. And also deals
with the transformation of heat energy from one to another form.
3.
Optics:- it deals with the prorogation,
reflection, refraction, dispersion, and wave properties of light.
4.
Electricity and magnetism:- it deals
with the study of charges at rest as well as in motion.
5.
Atomic physics:-it deals with the structure
and properties of an individual atom.
6.
Nucleus physics:- it deals
with the structure and properties of the nuclease of an atom.
7.
Solid-state physics:-it deals
with the properties of matter in solid-state.
8.
Particle physics:- it deals
with the study of elementary particles.
9.
Plasma physics:-which is the fourth state of
matter. And occurs in an ionized state.
10.
Quantum physics:-quanta is
studied is this branch which is the discrete and individuals particle of energy.
11.
Semiconductor physics:- whose
properties lie b/w conductor and insulator.
12.
Astrophysics:- it deals with the study of
heavenly bodies.
13.
Biophysics:- study of biology based on
the principle of physics is called biophysics.
14.
Geo physics:- it deals with the study of
earth and atmospheric.
15. Health
physics:- it deals with the study of diseases and their treatment.
Q.2 define
measurement, unit, and magnitude?
Measurement:-the comparison of an unknown
quantity with some standard is called measurement.
Unit:-the standard with which things are
compared is called unit-meter, kg, second.
Magnitude:- A number with a proper unit is called magnitude.
eg 3kg is magnitude.
Q.3 what is
meant by physical Quantities? Also, explain basic and derived quantizes?
Physical Quantity:- Those quantities which can be measured
are called physical quantities.
Basic quantities:-those physical quantities which are
not derived from other quantities and but other quantities are derived from
they are called basic quantities. These are seven in number. The units of basic
quantities are called basic units in the opposite table the units, quantities are seven
and symbols.