Tuesday, 27 October 2015

WHAT ARE PHYSICAL QUANTITIES?

There are some characteristics of every material object. These are to be measured to specify them. For example to specify the characteristics of a brick, its length, width, height and mass are to be measured. Such characteristics are called physical quantities.
Physical quantities are divided into two categories, base quantity and derived quantity.

(i) Base quantity: Base quantities are not defined in terms of other physical quantities such as length, time, mass etc
(ii) Derived Quantity: Derived quantities are those quantities whose definitions are based on other physical quantities; for example: volume, density, force etc.


WHAT IS MEANT BY UNITS?
To measure a physical quantity, we need to compare it with some standard quantity. While measuring a physical quantity, we have to see that how many times this quantity is bigger or smaller than the standard quantity. This standard quantity is called a unit.

(i) Base unit: The unit of base quantity is known as base unit such as Kilogram, Metre, Kelvin, etc. There are seven basic units in system international.
(ii) Derived unit: The unit of derived quantity is known as derived unit such as Newton, Watt, Joule, etc.


WHAT IS INTERNATIONAL SYSTEM OF UNITS?

Various standard units have been in use at different times in different parts of the world. With the passage of time, these units were made more refined and acceptable. The eleventh general conference of international committee on weights and measures recommended that all countries of the world should adopt a system of same kind of standard units. This conference recommended the use of a system consisting of seven base units known as international system of units. It is abbreviated as SI. This is system is in use all over the world.


 HOW TO DERIVE A UNIT FOR A QUANTITY?
The units of the derived quantities can be derived using the seven basic units.



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Monday, 19 October 2015

POINTS TO REMEMBER in Chapter 1

Here are some important points which I have selected from all previous posts, and write in shape of bullets. So you can read and remember for your knowledge.

1.                  Matter assumes the state of gas, comprising of ions and electrons, at a very high temperature. This is called Plasma.
2.                  Matter in the plasma phase makes up much of the universe.
3.                  The matter of sun is also in plasma state.
4.                  Energy obtained by breaking up 1 Kg of uranium is equal to the energy obtained from burning three million Kg of coal.
5.                  In the 14th century, scientist named Nicole Oresme studied the change in velocity with the help of geometry for the first time.
6.                  In the 16th century, Galileo studied freely falling bodies using modern scientific method.
7.                  The name of book of Isaac Newton is Principia Mathematica.
8.                  In the 17th century, Isaac Newton stated laws of motion and gravitation in his book.
9.                  In the 18th century, the electric cell was invented by Alesandro Volta.
10.              In the 20th century, Albert Einstein declared that mass and energy are forms of each other.
11.              In the 20th century, computer caused revolutionary changes in all areas of life.
12.              The radio telescope invented in the 20th century.
13.              Physics is the branch of science which deals with the study of properties of matter and energy and their mutual relationship.
14.              Physics has not only made progress in its own field but has also shown new avenues of research to other fields of knowledge.
15.              The first step of the scientific method is to make observations of a natural phenomenon.

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CONTRIBUTION OF MUSLIM SCIENTISTS IN THE FIELD OF SCIENCE

It is normally thought that Europeans received the light of scientific knowledge from Greek scientists but Greeks were ignorant of the arduous testing path to research and curiosity. Their theories were based on general observations. The true spirit of research, observation and experimentation was transferred to Europeans by Muslim scientists. Alberuni, Alkindi and Ibn-ul-Haithem are the pioneer Arabs whose researches were translated into European languages and they were made the stepping stone of knowledge for the European scientists.

1.                  Ibn-ul-Haithem
Introduction: He was born in Busra in 965 A.D. His full name was Ibn-ul-Haithm Abu Ali Hassan Bin Hussain.
Working: He was known for his exceptional work in the field of optics. He has invented pin hole camera by making a small hole in the window to see solar eclipse.
Books: His book name is Al-Manazir in which he discussed:-
·                     Nature of light that it is a form of energy
·                     Refraction of light that it deviates from its original path when enters from one medium to another.
·                     Research on spherical mirrors
·                     Working and internal structure of eye.

2.                  Al-Beruni
Introduction: He was born in about 973 A.D. in a village near Khawarzim. His full name was Abu Rehan Muhammad Bin Ahmad Al-Beruni.
Working: He was a famous physicist and an astronomer too. He revealed that the Indus valley was infact the basin of a big ocean which gradually filled with mud.
Books: His first book name is Qanoon-ul-Masoodi in which he discussed:-
·                    Measurement and shape of earth
·                    Movement of Sun and moon
·                    Shining and phases of moon
·                    Longitude and latitude of earth

His second book name is Kitab-ul-Astarlab in which he explained the methods of measuring:-
·                     Circumference of earth
·                     Depth of river
·                     Density of metals

3.                  Alkundi
Introduction: He was born in Busra in the 3rd century hijra. His full name was Yaqoob Ibn-e-Ishaq Alkundi.
Working: He was not only a philosopher but also a great scientist and physicist. He wrote books on sound and music which is now a days popular in European countries.

4.                  Dr. Abdus Salam
Introduction: Professor Dr. Abdus Salam is the only Pakistani scientist who was awarded the prestigious nobel prize in 1979.
Working: He has combined two basic forces of nature i.e., weak nuclear force and electromagnetic force.

5.                  Dr. Abdul Qadeer Khan
Introduction: Dr. Abdul Qadeer Khan is world renowned Pakistani atomic scientist. He is working as director of Dr. Abdul Qadeer Khan Laboratory.
Working: Under his supervision along with his fellow scientists six successful nuclear experiments were carried out on 28th May, 1998 at Chaghi in Baluchistan. And Pakistan became the seventh nuclear power in the world.

POINTS TO REMEMBER

1.                  Matter assumes the state of gas, comprising of ions and electrons, at a very high temperature. This is called Plasma.
2.                  Matter in the plasma phase makes up much of the universe.
3.                  The matter of sun is also in plasma state.
4.                  Energy obtained by breaking up 1 Kg of uranium is equal to the energy obtained from burning three million Kg of coal.
5.                  In the 14th century, scientist named Nicole Oresme studied the change in velocity with the help of geometry for the first time.
6.                  In the 16th century, Galileo studied freely falling bodies using modern scientific method.
7.                  The name of book of Isaac Newton is Principia Mathematica.
8.                  In the 17th century, Isaac Newton stated laws of motion and gravitation in his book.
9.                  In the 18th century, the electric cell was invented by Alesandro Volta.
10.              In the 20th century, Albert Einstein declared that mass and energy are forms of each other.
11.              In the 20th century, computer caused revolutionary changes in all areas of life.
12.              The radio telescope invented in the 20th century.
13.              Physics is the branch of science which deals with the study of properties of matter and energy and their mutual relationship.
14.              Physics has not only made progress in its own field but has also shown new avenues of research to other fields of knowledge.
15.              The first step of the scientific method is to make observations of a natural phenomenon.

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SCIENTIFIC METHOD

WHAT IS SCIENTIFIC METHOD?
Scientific method is a specific method used to search for truth. It is based on the following steps.

1.                  Observation
Definition: The first step in scientific method is to make observations of natural processes and to collect the data about them.
Example: It is a common observation that shadow of an opaque object formed when it is placed in the path of light coming from the Sun or lamp.

2.                  Hypothesis
Definition: On the basis of data collected through observations we can develop a hypothesis. This is done in order to test its logical results.
Example: We assume that shadow of opaque object is formed when they come in the path of light because light travels in a straight line.

3.                  Experiment
Definition: This is an organized repeatable process which is used to test the truth of the hypothesis.
Example: Three card boards A, B and C, each with a hole are placed in a straight line such that the hole in card A is in front of lamp. When we see through the hole in card C, we can see the light of the lamp. If any of these cards is replaced, we cannot see light through the hole C. thus this experiment proves that light travels in a straight line.

4.                  Theory
Definition: After the successful experimentation, the assumption becomes a theory and is applicable to similar phenomenon.
Example: Light always travels in a straight line.

5.                  Prediction
Definition: After the careful analysis of a theory we can make predictions about certain unknown aspects of nature.
Example: Light coming from a torch moves in a straight line.

6.                  Law
Definition: After verification of prediction through another experiment it becomes a law. Law is such a statement regarding the behaviour of nature which explains the observations and experiments of the past and can predict about other aspects of nature.
Example: The shadow of a ball will be round whereas the shadow of a rectangular block will be rectangle.

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PHYSICS & ITS BRANCHES

WHAT IS PHYSICS?

Physics is the branch of science which deals with the study of matter and energy and the mutual relationship between them.

Example: The study of Physics involves the investigation about many things like, how do motor cars move? How does an aeroplane fly? How is sound produced? etc

Branches of Physics:
Due to expanding scope and research in Physics, it is usually divided into following branches:

1.                  Mechanics
Definition: It is the branch of Physics which deals with the study of motion and the physical effects which influence motion.
Example: How does an object move? How does friction act along with motion? How velocity and acceleration is produced? Etc

2.                  Heat and Thermodynamics
Definition: It is the branch of Physics which deals with the thermal energy possessed by the molecules of matter and its use when it flows from one body to another.
Example: How does heat engine work? How does compressor work?

3.                  Sound
Definition: It is the branch of Physics which deals with the physical aspects of audible sound energy.
Example: How sound is produced? How sound travel from one location to another?

4.                  Light
Definition: It is the branch of Physics which deals with the physical aspects of visible light.
Example: How light travels? How light reflect? How light refract?

5.                  Electromagnetism
Definition: It is the branch of Physics which deals with the study of electromagnetic phenomena and mutual relationship between magnetism and electricity.
Example: How does transformer work?

6.                  Atomic and Molecular Physics
Definition: It is the branch of Physics which deals with the properties of atom and molecules.
Example: Structure of atoms and molecules. Radioactivity

7.                  Nuclear Physics
Definition: It is the branch of Physics which deals with the properties of isolated nuclei of atoms.
Example: Atomic bomb, Nuclear fission, Nuclear fusion.

8.                  Plasma Physics
Definition: It is the branch of Physics which deals with the study of matter in plasma state.
Example: Study about sun and different matter in plasma state.

9.                  Solid State Physics
Definition: It is the branch of Physics which deals with the specific properties of matter in solid form.
Example: classification of solids..

There are some branches of Physics under which we study the combined concepts of Physics and other branches of sciences.
1.                  Astrophysics
Definition: Astrology is the branch of science which deals with the heavenly bodies in space like planets and stars etc. So astrophysics deals with the branch of knowledge of heavenly bodies and interaction between matter and energy in space.
Example: The basis of universe.

2.                  Geophysics
Definition: Geology is the branch of science which deals with the study of earth. So geophysics deals with the study of the internal structure of earth in the light of Physics.
Example: Reasons of seismography

3.                  Biophysics
Definition: Biology is the branch of science which deals with the study of life and living organisms. So biophysics deals with the study of biological sciences on the basic principles of Physics.
Example: How do systems of nerve cells communicate?


Read More

1. Waves & Its Types
2. Simple Harmonic Motion
3. What are Physical Quantities?
4. Scientific Method



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