Whats Is Physics

Question 1

What is physics?

Answer 1

Physics is a pure science that deals with the behavior of matter and energy and how it relates with other physical properties.

Question 2

Physics is divided into how many main branches?

Answer 2

Two main branches

Question 3

Main branches of physics are?

Answer 3

Classical and Modern physics

Question 4

Classical physics contains?

Answer 4

Mechanics ,heat,optics,wave and sound,electricity and magnetism

Question 5

Modern physics consist of:

Answer 5

Matter,energy and their relations at atomic and subatomic levels.

Question 6

Who is a physicist?

Answer 6

The physicist is a person who studies and understand the reason for the existence of natural things and why they occur the way they do

Question 7

Isaac Newton

Answer 7

Isaac Newton provides a good understanding of motion and the effect of force.

Question 8

Neil Bohr

Answer 8

Neil Bohr gave us insight into the study of structural radiation of atom

Question 9

Gustuv hertz

Answer 9

Laws help in examining the collision between electrons and atoms

Question 10

Albert Einstein

Answer 10

Albert Einstein discovered the law of photoelectric effect,that gave the foundation for making of photocells used in burglary alarm and those achievements won them the Nobel prize

Question 11

What is theory?

Answer 11

Theory is a statement of fact which is only acceptable if there is an experimental evidence to support it

Question 12

What experiment does?

Answer 12

Experiment enables gathered data to be analyzed so as to examine how one parameter can relate with other physical properties.

Question 13

Types of errors

Answer 13

Systematic error,Random error,erratic error,zero error

Question 14

What is systematic error?

Answer 14

Systematic error is a type of error that affects measurements in a regular way due to undetected faulty apparatus or due to invisible influence on experimental procedures.examples the effect of air on the oscillation of a pendulum bob which invariably affects the period of oscillation.
This type of error can be discovered by using different procedures

Question 15

What is random error?

Answer 15

Random error occurs due to poor judgment in taking readings of the pointer instruments like ammeter,voltmeters e.t.c.it can also be expressed as that which occurs in trying to determine the time taken to complete a certain number of oscillation when a pendulum bob oscillates across its rest position
This type of error can however,be minimized by taking repeated readings and subsequently the mean value

Question 16

What is erratic errors?

Answer 16

Erratic errors occurs when experiments are hurriedly performed and the data obtained are totally or partially assumed. In most cases, the experimental set-up is faulty because of carelessness. This can be minimized by being more careful and not taking things on assumption.

Question 17

What is zero error?

Answer 17

Zero error is a type of error that is associated with pointer instruments or that which occurs in a wooden or plastic meter rule with worn out edges that affect the zero mark
In the case of zero error the pointer instruments is noted not to be at a zero mark
This error is taken care of by adding or subtracting the difference to the main scale reading.

Question 18

What is physics?

Answer 18

The nature around us is colourful and diverse. It contains phenomena of large varieties. The winds, the sands, the waters, the planets, the rainbow, heating of objects on rubbing, the function of a human body, the energy coming from the sun and the nucleus there are a large number of objects and events taking place around us.

Question 19

What is physics?

Answer 19

Physics is the study of nature and its laws. We expect that all these different events in nature take place according to some basic laws and revealing these laws of nature from the observed events is physics. For example, the orbiting of the moon around the earth, falling of an apple from a tree and tides in a sea on a full moon night can all be explained if we know the Newton’s law of gravitation and Newton’s laws of motion. Physics is concerned with the basic rules which are applicable to all domains of life. Understanding of physics, therefore, leads to applications in many fields including bio and medical sciences.

Question 20

About physics

Answer 20

The great physicist Dr R. P. Feynman has given a wonderful description of what is “understanding the nature”. Suppose we do not know the rules of chess but are allowed to watch the moves of the players. If we watch the game for a long time, we may make out some of the rules. With the knowledge of these rules we may try to understand why a player played a particular move. However, this may be a very difficult task. Even if we know all the rules of chess, it is not so simple to understand all the complications of a game in a given situation and predict the correct move. Knowing the basic rules is, however, the minimum requirement if any progress is to be made.

Question 21

About physics 1

Answer 21

Since physics is the study of nature, it is real. No one has been given the authority to frame the rules of physics. We only discover the rules that are operating in nature. Aryabhat, Newton, Einstein or Feynman are great physicists because from the observations available at that time, they could guess and frame the laws of physics which explained these observations in a convincing way. But there can be a new phenomenon any day and if the rules discovered by the great scientists are not able to explain this phenomenon, no one will hesitate to change these rules.

Question 22

Physics and mathematics

Answer 22

The description of nature becomes easy if we have the freedom to use mathematics. To say that the gravitational force between two masses is proportional to the product of the masses and is inversely proportional to the square of the distance apart, is more difficult than to write

Question 23

Relationships between physics and maths

Answer 23

Thus, mathematics is the language of physics. Without knowledge of mathematics it would be much more difficult to discover, understand and explain the laws of nature. The importance of mathematics in today’s world cannot be disputed. However, mathematics itself is not physics. We use a language to express our ideas. But the idea that we want to express has the main attention. If we are poor at grammar and vocabulary, it would be difficult for us to communicate our feelings but while doing so our basic interest is in the feeling that we want to express. It is nice to board a deluxe coach to go from Delhi to Agra, but the sweet memories of the deluxe coach and the video film shown on way are next to the prime goal of reaching Agra. “To understand nature” is physics, and mathematics is the deluxe coach to take us there comfortably. This relationship of physics and mathematics must be clearly understood and kept in mind while doing a physics course.

Question 24

About unit

Answer 24

Physics describes the laws of nature. This description is quantitative and involves measurement and comparison of physical quantities. To measure a physical quantity we need some standard unit of that quantity. An elephant is heavier than a goat but exactly how many times ? This question can be easily answered if we have chosen a standard mass calling it a unit mass. If the elephant is 200 times the unit mass and the goat is 20 times we know that the elephant is 10 times heavier than the goat. If I have the knowledge of the unit length and some one says that Gandhi Maidan is 5 times the unit length from here, I will have the idea whether I should walk down to Gandhi Maidan or I should ride a rickshaw or I should go by a bus. Thus, the physical quantities are quantitatively expressed in terms of a unit of that quantity. The measurement of the quantity is mentioned in two parts, the first part gives how many times of the standard unit and the second part gives the name of the unit. Thus, suppose I have to study for 2 hours. The numeric part 2 says that it is 2 times of the unit of time and the second part hour says that the unit chosen here is an hour.

Question 25

Who decides the unit?

Answer 25

How is a standard unit chosen for a physical quantity ? The first thing is that it should have international acceptance. Otherwise, everyone will choose his or her own unit for the quantity and it will be difficult to communicate freely among the persons distributed over the world. A body named Conference Generale des Poids et Mesures or CGPM also known as General Conference on Weight and Measures in English has been given the authority to decide the units by international agreement. It holds its meetings and any changes in standard units are communicated through the publications of the Conference.

Question 26

About unit

Answer 26

Physics describes the laws of nature. This description is quantitative and involves measurement and comparison of physical quantities. To measure a physical quantity we need some standard unit of that quantity. An elephant is heavier than a goat but exactly how many times ? This question can be easily answered if we have chosen a standard mass calling it a unit mass. If the elephant is 200 times the unit mass and the goat is 20 times we know that the elephant is 10 times heavier than the goat. If I have the knowledge of the unit length and some one says that Gandhi Maidan is 5 times the unit length from here, I will have the idea whether I should walk down to Gandhi Maidan or I should ride a rickshaw or I should go by a bus. Thus, the physical quantities are quantitatively expressed in terms of a unit of that quantity. The measurement of the quantity is mentioned in two parts, the first part gives how many times of the standard unit and the second part gives the name of the unit. Thus, suppose I have to study for 2 hours. The numeric part 2 says that it is 2 times of the unit of time and the second part hour says that the unit chosen here is an hour.

Question 27

Who decides the unit?

Answer 27

How is a standard unit chosen for a physical quantity ? The first thing is that it should have international acceptance. Otherwise, everyone will choose his or her own unit for the quantity and it will be difficult to communicate freely among the persons distributed over the world. A body named Conference Generale des Poids et Mesures or CGPM also known as General Conference on Weight and Measures in English has been given the authority to decide the units by international agreement. It holds its meetings and any changes in standard units are communicated through the publications of the Conference.

Question 28

Notes on fundamental and derived quantities 1

Answer 28

There are a large number of physical quantities which are measured and every quantity needs a definition of unit. However, not all the quantities are independent of each other. As a simple example, if a unit of length is defined, a unit of area is automatically obtained. If we make a square with its length equal to its breadth equal to the unit length, its area can be called the unit area. All areas can then be compared to this standard unit of area. Similarly, if a unit of length and a unit of time interval are defined, a unit of speed is automatically obtained. If a particle covers a unit length in unit time interval, we say that it has a unit speed. We can define a set of fundamental quantities as follows : (a) the fundamental quantities should be indepen- dent of each other, and (b) all other quantities may be expressed in terms of fundamental quantities

Question 29

Still on derived and fundamental quantities

Answer 29

It turns out that the number of fundamental quantities is only seven. All the rest may be derived from these quantities by multiplication and division. Many different choices can be made for the fundamental quantities. For example, one can take speed and time as fundamental quantities. Length is then a derived quantity. If something travels at unit speed, the distance it covers in unit time interval will be called a unit distance. One may also take length and time interval as the fundamental quantities and then speed will be a derived quantity. Several systems are in use over the world and in each system the fundamental quantities are selected in a particular way. The units defined for the fundamental quantities are called fundamental units and those obtained for the derived quantities are called the derived units.