Human Eye and Colourful World Test

Result

Human Eye and Colourful World Test - 35

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following is not an advantage of having two eyes?

A
It gives a wider field of view.

B
The ability to detect faint objects is enhanced with two detectors instead of one.

C
It gives the ability to interpret the closeness of an object.

D
It gives the eye higher protection from dust and pollution.

Solution

There are several advantages of having two eyes instead of one.
(i) It gives a wider field view because human being has a horizontal field view of about $$150^o$$ with one eye and of about $$ 180^o$$ 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.
Thus, option $$D$$.
Question 2
1 / -0

A student has difficulty in reading the blackboard while sitting in the last row. From the given options, choose the defect child is suffering from and its correction measures :

A
Defect: Myopia
Correction: Concave lens of suitable focal length

B
Defect: Hypermetropia
Correction: Convex lens of suitable focal length

C
Defect: Myopia
Correction: Medicines

D
Defect: Hypermetropia
Correction: Medicines

Solution

$$Answer:-$$ Myopia or Short sightedness
It can be corrected using a concave lens since due to myopia light entering the eye converges before retina so by using diverging lens (concave ) rays are converged onto retina.
Question 3
1 / -0

Which of the following figures correctly represents the passage of white light through a prism ?

A

B

C

D

Solution

White light, while passing through a prism, disperses into its seven constituent colours (VIBGYOR). Out of these seven colours, Violet deviates the most and Red deviates the least.
So, Option A represents the situation correctly.
Question 4
1 / -0

Sometimes, a person suffers from both the defects, myopia and hypermetropia. Which of the following is used to correct this defect?

A
Convex lens

B
Concave lens

C
Bifocal lens

D
Cylindrical lens

Solution

The power of accommodation of the eye usually decreases with aging. For most people, the near point gradually recedes away. They find it difficult to see nearby objects comfortably and distinctly without corrective eyeglasses. This defect is called Presbyopia. It arises due to the gradual weakening of the ciliary muscles and diminishing flexibility of the eye lens. A person who suffers from both defects, myopia, and hypermetropia uses a bifocal lens to correct this defect. A common type of bi-focal lenses consists of both concave and convex lenses. The upper portion consists of a concave lens. It facilitates distant vision. The lower part is a convex lens. It facilitates near vision.
Question 5
1 / -0

Identify the defect in the eye shown in the figure.

A
Hypermetropia

B
Myopia

C
Astigmatism

D
Night blindness

Solution

In the above diagram, the rays that are coming from a faraway distance converge before the retina. So in this defect, the person can't see the distant objects. This defect is myopia.

So option B is the answer.
Question 6
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While a white light ray, passes through a glass prism, the colour which deviates the least is:

A
violet

B
red

C
orange

D
None of these

Solution

Correct answer is (b)

Spectrum of visible light runs from violet to red, which is banded on either side by ultraviolet and infrared rays.

The deviation of light is inversely proportional to the wavelength. Since, red light has the longest wavelength among the seven colours with about 650 nm. Hence its deviation is the least among all colours.
Question 7
1 / -0

Identify the defect which is corrected in the attached figure.

A
Hypermetropia

B
Myopia

C
Astigmatism

D
Night Blindness

Solution

Shortsightedness or myopia is corrected using a concave (curved inwards) lens which is placed in front of a myopic eye, moving the image back to the retina and making it clearer.
Question 8
1 / -0

The figure illustrates correction of vision for a certain defect of human eye. Identify the defect which is corrected here.

A
Myopia

B
Hypermetropia

C
Astigmatism

D
Nigh Blindness

Solution

The defect corrected here is Hypermetropia or far-sightedness. In Hypermetropia, light rays from nearby objects are focused by the eye-lens at a point behind the retina. To correct this defect, a convex lens of appropriate power is used. The presence of this convex lens helps the light rays to get focused on the retina.
Question 9
1 / -0

With age 'Near point' and 'Far point' recedes due to
A. Weakening of ciliary muscles
B. decreasing ability to change the focal length

A
A is correct

B
B is correct

C
Both A and B are correct

D
Neither A nor B is correct

Solution

Presbyopia is a natural part of the aging process. It happens due to the hardening of the eye lens causing the eye to focus light behind the retina when looking at close objects. It is a type of refractive error of the eye along with nearsightedness, farsightedness and astigmatism.
This occurs due to the inability of Ciliary muscles to adjust and change focal length.
Question 10
1 / -0

The human eye can focus objects at different distances by adjusting the focal length of the eye.
This is due to:

A
Presbyopia

B
Accommodation

C
Near-sightedness

D
Far-sightedness

Solution

Due to Accommodation, the human eye can focus objects at different distances.
The accommodation of an eye is its reflex to adjust itself in response to focusing on a near object and then suddenly focusing on a faraway object.

Option B is correct.