Two identical concave mirrors each of focal length $ f $ are facing each other as shown. A glass slab of thickness $ t $ and refractive index $ n_0 $ is placed equidistant from both mirrors on the principal axis. A monochromatic point source $ S $ is placed at the center of the slab. For the image to be formed on $ S $ itself, which of the following distances between the two mirrors is/are correct:
It is a set of 3 mutually perpendicular axes and a convenient way to represent a set of numbers (2 or 3) or a point in space.
Hence, we have a way to represent an imaginary number graphically. All we need to do is to find the real part and an imaginary part of it. Then, represent them on the two mutually perpendicular number lines. The point of intersection, as shown in the above diagram, is the origin of our Plane.
The formation of the Plane so formed is known as the Argand Plane and it is a convenient way to represent an imaginary number graphically.