# Physical World and Measurement

## Physical World and Measurement Class 11 Notes

Nature of the physical world

The world that is composed of materials that have no life is called the physical world. That means the world consisting of brick, stone, iron, gold, earth, etc is called the physical world.

Four elements of the physical world

The physical world basically consists of four elements. These are -

1) space,

2) time,

3) mass and

4) energy.

Actually, the physical world is represented by the presence of mass and energy. In this case, mass and energy are complementary to each other. So, the physical world is represented by three elements.

The physical world is vast and diverse. People have realized this while doing research on it. That is why scientific laws are not considered universal.

There are two amazing ways to understand the diversity of the physical world. One is to see the physical world from small to smaller and the other is to see the world from large to larger.

Scope of physics and its wonderful contributions in different fields

Scope of Physics

Physics is the key to science. Physics is the principal branch of other sciences. Because its principles have created the basis of other sciences. For example, physics is extended from the structure of atoms and molecules to the forecast of the weather. For the convenience of studying and for detailed discussions physics has been divided into different branches, namely-

1) General Physics

2) Heat

3) Sound

4) Light

5) Magnetism

6) Electricity

7) Electronics

8) Atomic Physics, etc.

General Physics is again sub-divided into two groups, namely-

1) Mechanics

2) Properties of Matter

Mechanics discusses many topics on the action of force on the matter. Properties of matter discuss the various properties of matter.

Mechanics are again classified into two groups, namely-

1) Statics and

2) Dynamics.

Statics discusses the effect of force on bodies at rest and dynamics deals with the effect of force on moving bodies.

There are some characteristics or properties of matter. These are combinedly called properties of matter. Properties of matter are of two types, namely-

1) General Property and

2) Special Property

Properties that are associated more or less with all the bodies are called general properties. For example, weight, expansion, resistance, elasticity, etc.

The properties which are not associated with all the bodies are called special properties. For example, viscosity, rigidity, fragility, etc. are special properties of solids. Viscosity is the special property of liquids and gases. Surface tension is the special property of liquid.

The scope of physics is well extended. It is a milestone in the development of human civilization. It is especially useful for human beings in all spheres of life. Without the help of physics, it is quite impossible to know anything about the universe. Its sphere is extended from the infinite sky to the interior of an atom. Wherever there is matter and energy, there is physics to do something. So, it is the duty of every citizen to get involved in the study of physics as a carrier of general education. The extensiveness of physics and its use plays an important role in human welfare.

Wonderful contribution of physics in different fields

The contribution of physics to the welfare of mankind is enormous. We get enough comfort, pleasure, and amenities in our daily life from different energies. Only electric energy has been used in so many areas of development in our life that it is no exaggeration to call the present age, the age of electricity. Electric fans, electric bulbs, electric heaters, telephones, television, radio, motor, electric train, machines, and factories are run by electricity.

Errors in measurements

## Questions

What is Law?

What is Principle?

What is Postulate?

What is Hypothesis?

What is substitute?

What is Theory?

What is Science?

What is Physics?

What is formula?

What is symmetry?

What is derived unit?

What is base unit?

What is dimensions?

What is a spherometer used for?

What is fundamental unit?

What is pitch?

What is vernier constant?

What is least count?

What is accuracy of measurement?

What is the unit of measurement?

What is 1 ampere?

What is 1 kilogram?

What is a dimensional equation?

In what case did Newton use Galileo's principle?

What is measurement error?

What is absolute error?

What is parallax error?

What is backlash error?

What is offset error?

What is zero of spherometer?

Represent the modern concept of space and time.

Differentiate between fundamental and derived units.

Explain instrumental error.

Represents the mathematical expression of probability.

Differentiate vernier constant and Least count.

Differentiate between formula theory.

Why aren't the relativity postulates of Einstein called supposition?

No Comment