Question

The human eye part that can be used again and again for forming different images is called
(A) Iris
(B) Pupil
(C) Cornea
(D) Retina

Answer 1

In the human eye, the image forms on the retina which consists of layers of cells that transmits the information to the brain. Within a 16th of a second, a new image is formed which is then transmitted again. So the retina has to be used again and again to form the images.

Complete answer:
Our human eye is an organ that reacts to light which gives us vision.
The front part of the eye is known as the cornea. It is a transparent substance that is convex in shape. The light rays enter our eyes through the cornea. The iris is situated just behind the cornea. The iris is also called the coloured diaphragm and the hole in the middle of the iris is called the pupil.
Behind them are the eye lens and the retina. The retina is a surface where the images get formed. It is a thin layer of tissues on the back of the eye. It receives the light that the lens focuses on and converts the image into neural signals that are then transmitted to the brain. We can see that from this image,

The retina forms a new image on its surface every 16th of a second and then transmits that to the brain. So the images formed on it are not permanent and hence it is used again and again by the eye.
Therefore the human eye part that can be used again and again for forming images is called the retina.
So the correct answer is option D.

Note:
Due to the vital role of the retina in the process of vision, any damage to it can cause permanent blindness. Sometimes there are conditions where the retina gets abnormally detached from their usual positions. This condition is termed as the retinal detachment. It prevents the retina from receiving or processing light and therefore transmitting signals to the brain thus leading to permanent blindness.