## What is albert einstein’s theory of relativity?

Theory of relativity is given by Albert Einstein in 1905 which states that there is no absolute state exist in the universe,all states are relative.

### Types of relativity:

There are two types of relativity:

- General theory of relativity
- Special theory of relativity

### What is the general theory of relativity?

It belongs to the accelerative motion of object and frame of reference.

### What is the special theory of relativity?

It belongs to uniform motion relative of objects or inertial frame of reference.

## What are the two Postulates of special relativity?

Special theory of relativity based upon some assumptions which are called postulates of special relativity.These postulates are given as:

- There is no absolute inertial frame of reference.All frames are equivalent to describe all laws of physics.
- The speed of light in vacuum always remains same and not depends upon relative motion of observer.

## What are the consequences of Einstein’s special theory of relativity?

**Mass variation:**

If an object is moving with such a high speed that comparable to the speed of light then mass of object is change which can be determine as follows:

**Length contraction**

If an object is moving such a high speed that comparable to the speed of light then its length become smaller along the direction of motion which can be determine as:

**Time dilation**

If a clock is lying in an inertial frame of reference that is moving such a high speed which comparable to the speed of light then it observed that the clock is going slow,which means that needle of second take long time to transfer from one digit to other this phenomenon is called time dilation.It is calculated as:

**Mass energy relation**

It is the famous relation which is called Mass energy relation .According to this relation mass can be converted into energy and energy in mass.This relation is given as:

where

m=mass of moving object

m0=mass of object in rest

L0=length of object in rest

L= length of moving object

v=velocity of moving object

c= speed of light