Tag: the human eye and the colourful world

Human eye cannot differentiate two images when the interval of separation between them is less than one-tenth of a second

Correct answer is (D)

Iris is the ring of pigmented tissue surrounding the pupil that varies in color from person to person, it contract and dilates to control the amount of light entering the eye through the pupil. The pupil is the opening in the center of the iris where light enters the eye. 

According to Persistence of Vision theory, the human eye has the illusion of an after image still persisting. It is when our eye has the ability to persist for 1/16 of a second after the image has removed. It is used in animation to show fluent movement, normally after every two frames one picture would be shown, so for every 24 frames 12 pictures will be shown. This gives us the illusion of movement and the afterimage persists on our retina. 

There are several advantages of our having two eyes instead of one.
(i) It gives a wider field view because human being has a horizontal field view of about 150∘150∘ with one eye and of about 180∘180∘with two eyes.
(ii) The ability to detect faint objects is enhanced with two detectors instead of one.
(iii) With one eye, the world looks flat, i.e., two dimensional-only. With two eyes, the view is three dimensional.
As our two eyes are separated by a few centimeters each eye observes a slightly different image. Our brain combines the two views into one and we get to know how close or far away the things observed are.

The space between the cornea and the lens is called the aqueous chamber and contains a thin watery fluid called aqueous humor.

Correct answer ( B )

Circular aperture through which light enters the eye is known as pupil.It is the black circle in the center of the iris, when the light reaches the tissues at the back of the eye, it is absorbed making the pupil look black. The pupil controls the amount of light that enters the eye.

The ciliary muscle is located in the eye and surrounds the lens. It contracts or relaxes in order for an individual to see at multiple distances. When it contracts, it pulls forward, moving to a frontal portion to relax the fibers that hold the lens in place; this process also allows it to take on a more spherical shape to provide short range focus.

Eye lens refract the light and form image on retina of eye .

At the junction from where optic nerve enters eye, there are no cone or rod cells to sense the image , and hence no vision is possible at that spot.Hence, it is called blind spot.