Physics:
Physics is that branch
of science, which deals with matter, energy and their interaction.
History of Physics:
· The
people of Euphrates and Tigris valley were aware of calendar and they had the
“knowledge of Geometry”
· The
people of Indus valley were the pioneers of decimal system.
· Chinese
were the first to make paper (papytue).
· The
Glorious Islamic Era was between the eight to thirteen century A.D.
· The
achievements of well-known scientists of Glorious Era are:
Ibn-ul-Haisham:
· Discovered
the nature of light, declared it as a form of energy.
· The
first to give two laws of reflection of light.
· Constructed
a pin hole camera.
· Gave
description of luminous, non-luminous, opaque and transparent objects.
· The
remarkable discovery of him was that. “The ray of light passing through a
medium takes a path which takes the least time”.
· The
first comprehensive book on light was his book “Kitab-ul-manazir”.
Al-beruni:
· Gave
the conclusion that speed of light is greater than speed of Sound.
· His
book “Kitab-ul-Qanoon-ul-Masoodi” is considered as encyclopedia of astronomy.
· He
was the first who calculate the diameter of earth.
Al-Khwarizmi:
· Was
the founder of algebra and wrote a first book in the world of algebra known as
“Al-Jabral-Muqabla”.
· He
gave geometrical solution of linear and quadratic equations.
· He
invented “ Monographs” named “ Hisab” in which he introduce the method of
counting based on numerals.
· Invented
the term “logrithms”.
Yaqoob-Al-Kindi:
· The
first Arab Philosphere.
· Wrote
research monographs on “ Meterology” “specific gravity and tides”.
· Explain
the appearance of the blue colour of the sky.
Al-Razi:
·
The most prominent and greatest
physician wrote about 200 original monographs, most of them pertained to
medicine.
Ibn-e-Sina:
·
Famous for his research in medicine.
·
Discover use of Catheters.
·
Gave intravention injection by means of
a silver syringe.
·
“Al-Qanoon-Fil-Tib” is the famous of
medicine.
·
Al-shifa an encyclopedia of philosophy.
Umar Khayam:
· Was
one of the prominent mathematicians and remarkable poet of the Islamic world.
Al-Battani:
·
Made calculations is connection with
solar system, change in seasons, eclipse of the moon and sun and other
astronomical phenomenon.
Units and Measurements:
·
Physics is a quantitative science
concerned with relationship between careful measurements of well-defined
physical quantities.
·
The basic quantities selected for convenience
is mass, length, time, electric current, temperature, luminous intensity and
amount of substance.
·
The unit of a physical quantity is a
value of its in terms of which other quantities of that kind are expressed. It
is chosen arbitrarily but then agreed upon universally.
·
There are four system of units:
Ø Centimeter-Gram-Second
(C.G.S) system.
Ø Foot-Pound-Second
(F.P.S) system.
Ø Meter-Kilogram-Second
(M.K.S) system.
Ø International
System (S.I) system.
· The
units used to measure basic or fundamental quantities are called fundamental
units.
· International
system of units (S.I) was adopted to overcome the difficulties of large number
of multiples and submultiple units, and also due to large no of conversion
factors.
· This
System also called MKSA (Meter-Kilogram-Second-Ampere) system.
The table of fundamental units of S.I system is
given below.
Physical
Quantity
|
S.I
units
|
Abbreviation
|
Length
|
meter
|
M
|
Mass
|
Kilogram
|
Kg
|
Time
|
Second
|
Sec
|
Temperature
|
Kelvin
|
K
|
Current
|
Ampere
|
A
|
Luminous
Intensity
|
Candela
|
Cd
|
Amount
of Substance
|
Mole
|
Mol
|
Supplementary Units:
·
Units of angle is radian, which is the
angle subtended by an arc of a circle at the center of it having the same lengths
as that of the radius of the circle.
·
Units of solid angle ids steradian, which
is the angle subtended by the area of a base at vertex of the cone.
Derived Units:
·
The units which are obtained with the
help of two or more fundamental units are called derived units.
Physical Quantity
|
Symbol of
Quantity
|
Name of units
|
Symbol for units
|
Speed
|
V
|
Meter
per sec
|
m/ses
|
Acceleration
|
A
|
Meter
per sec square
|
m/sec2
|
Force
|
F
|
Newton
|
N
|
Pressure
|
P
|
Pascal
|
Pa(
N/m2)
|
Frequency
|
Y
|
Hertz
|
Hz
|
Area
|
A
|
Meter
square
|
M2
|
Charge
|
Q
|
coulomb
|
C(As)
|
Power
|
P
|
Watt
|
W(J/sec)
|
Prefixes:
Decca
|
D
|
101
|
Deci
|
d
|
10-1
|
Hecto
|
H
|
102
|
Centi
|
c
|
10-2
|
Kilo
|
K
|
103
|
Milli
|
m
|
10-3
|
Mega
|
M
|
104
|
Micro
|
u
|
10-4
|
Giga
|
G
|
105
|
Nano
|
n
|
10-5
|
Tera
|
T
|
106
|
Pico
|
p
|
10-6
|
Significant Figures:
· Significant figures are reliable digits known with certainty
in a given number.
· The
number of significant figures refer to the precision and accuracy of measured
quantity. In this numbers the last digit may not be precisely mentioned, the
value of last digit is uncertain.
· Rules
for determining significant figure:
Ø All non-zero digits are significant. E.g. 364
have 3 significant figures. 0.64 has 2 significant
figures.
Ø Zero
between non zero digits are significant. E.g 7005 has 4 significant figures.
Ø Zero
locating the decimal points in number, less than1 is not significant. E.g 0.065 has 2 and 0.001 has only one
significant figures.
Ø Final
zeros to the right of the decimal point are significant. E.g 4.000 has 4
significant figures.
Ø Zeros
that locate the decimal point in numbers larger than one are not necessarily significant.
E.g 40 have one significant figure.
Dimensions:
·
Dimension is the
power to which a fundamental quantity is raised.
·
Dimensional
formula is an expression which tells the involvement of the fundamental unit in
a physical quantity. In general for a physical quantity “a” dimension in mass “b”
in length and “c” in time then X=MaLbTc.
·
Principle of homogeneity
of a dimensional equation is states that the dimensions on both sides of the
equation must be equal.
·
Dimensional
equation is used to
o Check the correctness of a physical relation.
o Convert one system of units into another.
o Derive various physical relations.
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