Tag: human eye and its working

Questions Related to human eye and its working

Sclera is a grey-white membrane, which darkens the eye ball from inside.

  1. True

  2. False


Correct Option: A
Explanation:

Sclera is the white membrane which lines the eyeball. It is the supporting wall of the eye and acts as a protective coating. It is seen in contrast with the iris.

Cilliary muscles in the eye:

  1. hold the eye lens in place

  2. increase or decrease focal length of eye lens.

  3. both (a) and (b)

  4. none of these


Correct Option: B
Explanation:

When the ciliary muscle is relaxed, the choroid acts like a spring pulling on the lens via the zonule fibers causing the lens to become flat. When the ciliary muscle contracts, it stretches the choroid, releasing the tension on the lens and the lens becomes thicker. Cilliary muscles in the eye increase or decrease focal length of eye lens.

The nature of image formed on the retina of human eye is:

  1. virtual and erect

  2. virtual and inverted

  3. real and erect

  4. real and inverted


Correct Option: D
Explanation:

Human eye lens are convex in nature and form real and inverted images and when the object is kept before the focus point and the centre of the lens it form virtual and erect images. The image formed on retina are real and inverted and further the message sent by the optic nerve are chemical impulses to the brain, which turn them into erect images that we see with our eyes.

Which of the following statements about human eye is NOT true?

  1. the iris gives a distinct colour to the eye

  2. the yellow spot is extremely sensitive to light

  3. the space between lens and cornea is filled with ciliary muscles

  4. the optic nerves enters the eye near the blind spot


Correct Option: C
Explanation:


The space between the cornea and the lens is called the aqueous chamber and filled with thin watery transparent viscous fluid called aqueous humor which supplies nutrients to these structures as well as to the lens. Aqueous humour is produced by the ciliary processes in the posterior chamber and flows into the anterior chamber through the pupil.

The cornea gives the colour of the eye.

  1. True

  2. False


Correct Option: B
Explanation:

The iris gives eyes their color, depending on how much melanin it contains, similar to the pigment found in skin. Also helping to determine color is the iris's front layer, or stroma, which contains melanocyte cells that produce melanin, and fibers that scatter the light reflected outward.
Hence, the statement is false.

The impression of an image does not vanish immediately from the retina. It persists there for about $1/6^{th}$ of a second.

  1. True

  2. False


Correct Option: A
Explanation:

It is known as persistent of vision which is the time for which an image persists in our retina.

There is a pattern observed in the number of sum spots appearing every year called as

  1. solar cycle

  2. sun spot cycle

  3. solar period

  4. solar spot cycle


Correct Option: B
Explanation:

Sun spot cycle is a pattern observed in number of sun spots appearing every year due to revolution of earth arround sun with moon revolving earth.

The eye lens contains a watery liquid called the :

  1. aqueous humour

  2. peroxide

  3. vitreous humour

  4. magic water


Correct Option: A
Explanation:

Aqueous humor is low concentration protien liquid in eye lens.

lens of an eye is a transparent spherical structure which :

  1. reflects light

  2. scatters light

  3. refracts light

  4. diffracts light


Correct Option: C
Explanation:

The lens is a transparent structure behind the iris, the coloured part of the eye. The lens bends light rays so that they form a clear image at the back of the eye – on the retina. As the lens is elastic, it can change shape, getting fatter to focus close objects and thinner for distant objects.

The eye lens is a :

  1. transparent double-convex lens

  2. transparent double-concave lens

  3. transparent concavo-convex lens

  4. transparent convex mirror


Correct Option: A
Explanation:

The eyelens is adjustable focus double convex lens so that a real image is formed in retina.