Question

What are the $4$ dimensions?

Answer 1

In order to solve this question, we should know about the term dimensions. In physics and in our physical universe, Dimensions are the number of coordinates required to represent a particular event in space-time. Here, we will discuss each of four dimensions of our physical universe.

Complete step by step solution:
Our whole universe lies in the space-time fabric of physical existence. To locate a particular event in space we require a minimum of four informations or coordinates, these four coordinates are called four dimensions of space-time.
In Three-Dimensional space, we need three coordinate to specify the location of any point in space so, First dimension is Length: This is the numerical value of distance of a point in three dimensional space in a line that connects the point and the chosen point from where this distance is measured.
Second Dimension is Breadth: This is the perpendicular distance between the point and the first dimension line segment which is length.
Third dimension is Height: This is the perpendicular distance to both dimensions length and breadth to the point in space.
So, the first three dimensions are simply the length, breadth and height of a point in three dimensional space, and Fourth dimension is time which is unidirectional, to specify at what time a particular event occurs in space we choose Time as the fourth dimension.
Hence, $4$ dimensions are Length, Breadth, Height, Time.

Note: It should be remembered that, first three dimensions are simply represent three axes of three dimensional Cartesian system namely X-axes, Y-axes, Z-axes and fourth one is time and in relativistic mechanics the location of any event in space-time is written in the form of four dimensions as $(x,y,z,t)$ .