Tag: human eye and its working

Questions Related to human eye and its working

A parallel beam of light falling on the eye gets focused on the retina because of refraction at

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. the cornea

  2. the crystalline lens

  3. the vitreous humor

  4. various surfaces in the eye

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Correct Option: A
Explanation:

Most of the refraction for the light rays entering the eye occurs at the outer surface of the cornea.

State whether true or false :

Pupil controls the amount of light entering an eye.

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. True

  2. False

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Correct Option: A
Explanation:

True

The iris is the ring of pigmented tissue surrounding the pupil that varies in color. The iris opens and closes 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.

The dark muscular diaphragm in the human eye that controls the pupil is:

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Iris

  2. Retina

  3. Cornea

  4. Sclera

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Correct Option: A
Explanation:

A. Iris is the muscular diaphragm in the human eye that controls the pupil.

B. Retina is a layer at the back of the eyeball that contains cells sensitive to light, which trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.
C. Cornea is the transparent layer forming the front of the eye.
D. Sclera is the white outer layer of the eyeball. At the front of the eye it is continuous with the cornea.

In long sightedness image is formed-

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. On Retina

  2. Infront of Retina

  3. Behind Retina

  4. On blind spot

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Correct Option: C
Explanation:

In long sightedness eyes ball's size decrease or focal length of the lens increase due to which image will form behind in the retina.

Name the part of the eye which gives colour to the eyes.

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Retina

  2. Iris

  3. Cornea

  4. Fovea

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Correct Option: B
Explanation:

The iris is the area of the eye that contains the pigment which gives the eye its colour.

Our eyes function similar to a:

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Convex lens

  2. Concave lens

  3. Cylindrical lens

  4. None of these

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Correct Option: A
Explanation:

In eye light passes through the eye's lens and falls on the retina. The mechanism is same as a convex lens converges parallel beams of light in its focus.

When the light is very bright, then:

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Iris makes pupil expand

  2. Iris makes pupil contract

  3. Iris and pupil remain as they are

  4. None of these

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Correct Option: B
Explanation:

When the light is very bright, then iris makes the pupil contract so that less amount of light enters into the eye.

Our eye lens is held in position by :

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Rods and cones

  2. Iris and pupil

  3. Ciliary muscles

  4. None of these

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Correct Option: C
Explanation:

The ciliary muscle is found in the middle layer of eye.  It is responsible for viewing objects at various distances. It helps to change the shape of the lens within the eye and holds it in position.

Image on the retina remains for:

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. 20 s

  2. 10 s

  3. $\dfrac {1}{100}s$

  4. $\dfrac {1}{20}s$

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Correct Option: D
Explanation:

Image on the retina remains for 1/20 sec.

Middle vascular coat that darkens the eye chamber and prevents refraction by absorbing the light rays is:

physics the human eye and the colourful world human eye and its working what is inside our eyes? human eye and defects of vision

  1. Choroid

  2. Sclera

  3. Retina

  4. Cornea

Show answer
Correct Option: A
Explanation:

Middle vascular coat that darkens the eye chamber and prevents refraction by absorbing the light rays is choroid.