Human Eye and Colourful World Test

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Human Eye and Colourful World Test - 42

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Weekly Quiz Competition

Question 1
1 / -0

Long sightedness happens as:

A
ciliary muscles tighten

B
ciliary muscles weaken

C
eyeball size does not change

D
all the above happen

Solution

As we grow old, due to some defect, ciliary muscles become hard and thus can not contract. Thus curvature and focal length of the eye cannot be decreased. So the image is formed behind the retina.
Question 2
1 / -0

A girl viewed an object and found that it is not clearly visible to her. It was found that the image was formed by her eye lens $$3cm$$ away from the pupil of her eyes.The girl can correct this defect by using a:

A
concave lens

B
convex lens

C
bi-focal lens

D
plano-convex lens

Solution

Since the distance between pupil and retina is $$2.3 cm$$ and the image formed is at a distance of $$3 cm$$ from the pupil, it is obvious that the image is formed behind the retina.
This defect is known as hyper-metropia which happens because converging power of eyes lens reduces
So to correct this defect of vision, the girl needs to use a convex lens. It will form the image at the retina by increasing the combined power.
Question 3
1 / -0

Near point of an eye suffering from long-sightedness is:

A
less than 25cm

B
greater than 25cm

C
equal to 25cm

D
infinity

Solution

In long sightedness, for close objects image is formed behind the retina. This is because the near point of the eye shifts to a distance greater than $$25 \ cm$$ for the eye due to shortening of eyeball.
Question 4
1 / -0

The farthest point, upto which the eye can see objects clearly, is called ________, and is ________ for a normal eye.

A
near point, $$50cm$$

B
power of accommodation, $$100m$$

C
far point, infinity

D
range of vision, $$25cm$$

Solution

The farthest point upto which the eye can see objects clearly is called far point. For normal eye, the far point is at infinity.
Question 5
1 / -0

What is the black circular aperture in our eyes and why does it appear black?

A
The aperture is known as iris and it appears black as no light is reflected from it.

B
The aperture is known as the pupil and it appears black as all light is reflected from it.

C
The aperture is known as iris and it appears black as all light is reflected from it.

D
The aperture is known as the pupil and it appears black as no light is reflected from it.

Solution

A small aperture is present at the center of the iris. The size of the aperture is variable and self-adjustable. This aperture is known as the pupil. The pupil appears black as no light is reflected from it.

Question 6

1 / -0

Match the columns

i. amount of light entering into eye controlled by	a. rodes
ii. colour sensing cells	b. cones
iii.cells helping in vision in dim light	c. iris
iv. junction of optic nerve and retina	d. blindspot

i-a,ii-b,iii-c,iv-d

i-d,ii-c,iii-b-iv-a

i-c,ii-b,iii-a,iv-d

i-b,ii-a,iii-c,iv-b

Solution

Iris controls the amount of light entering the eye.

Cones are colour sensing cells.

Rode cells help in vision in dim light.

At the junction of optic nerve and retina there are no rodes and cones.No image is formed at this point as it is insensitive to light.This point is called blind spot.

Question 7
1 / -0

Match the columns:
i. convex lens a. presbyopia
ii. concave lens b. cataract
iii. Artificial lens c. myopia
iv. focal lens d. hypermetropia

A
i-c,ii-d,iii-a,iv-b

B
i-d,ii-c,iii-b,iv-a

C
i-b,ii-c,iii-a,iv-d

D
i-a,ii-b-iii-d,iv-c

Solution

Myopia ,near sightedness is corrected by concave lens.
Hypermetropia or, far sightedness is corrected by convex lens.
In cataract natural faulty lens is replaced by artificial lens.
Bi-focal lens is used in presbyopia which generally occurs in old persons.
Question 8
1 / -0

Fill in the blanks:
For a human eye lens, for nearby objects, focal length ____ while for far away objects focal length ____ .

A
remains the same, decreases

B
increases, decreases

C
decreases, increases

D
increases, remains the same

Solution

The curvature of the eye lens can be modified to change its focal length to some extent by the ciliary muscles. When the ciliary muscles contract, the focal length of the eye decreases enabling us to see nearby objects clearly. Similarly, when the muscles are relaxed, the focal length increases. This enables us to see distant objects clearly.
Question 9
1 / -0

Match the following
List I List II
1 Adjustment of focal length a Accommodation
2 Least distance of distinct vision b Infinity
3 Farthest point of visibility c 25 cm
4 Vision impairment d Cataract

A
1-b, 2-c, 3-a, 4-d

B
1-d, 2-c, 3-b, 4-a

C
1-a, 2-c, 3-b, 4-d

D
1-c, 2-a, 3-d, 4-b

Solution

The change in the curvature of the eye lens can change its focal length to facilitate clear vision of close or far away objects. The ability of the eye lens to adjust its focal length is called accommodation. The least distance of distinct vision for a young adult with normal vision is about 25 cm. The farthest point up to which the normal eye can see objects clearly is infinity.
A cataract is a vision impairment which involves clouding of the normally clear lens of your eye. For people who have cataracts, seeing through cloudy lenses is a bit like looking through a frosty or fogged-up window.
Question 10
1 / -0

The minimum distance at which objects can be seen without any strain is

A
$$25\ cm$$

B
Near point

C
Least distance of distinct vision

D
All of the above

Solution

To see an object comfortably and distinctly, it must be held at about $$25\ cm$$ from the eyes. The minimum distance, at which objects can be seen most distinctly without strain, is called the least distance of distinct vision or near point of the eye. For a young adult with normal vision, the near point is about $$25\ cm.$$

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Re-Attempt Weekly Quiz Competition

i. convex lens	a. presbyopia
ii. concave lens	b. cataract
iii. Artificial lens	c. myopia
iv. focal lens	d. hypermetropia

	List I		List II
1	Adjustment of focal length	a	Accommodation
2	Least distance of distinct vision	b	Infinity
3	Farthest point of visibility	c	25 cm
4	Vision impairment	d	Cataract

Human Eye and Colourful World Test - 42

Result

Human Eye and Colourful World Test - 42

Score

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Rank

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SHARING IS CARING

Question 1

ciliary muscles tighten

ciliary muscles weaken

eyeball size does not change

all the above happen

Solution

Question 2

concave lens

convex lens

bi-focal lens

plano-convex lens

Solution

Question 3

less than 25cm

greater than 25cm

equal to 25cm

infinity

Solution

Question 4

near point, $$50cm$$

power of accommodation, $$100m$$

far point, infinity

range of vision, $$25cm$$

Solution

Question 5

The aperture is known as iris and it appears black as no light is reflected from it.

The aperture is known as the pupil and it appears black as all light is reflected from it.

The aperture is known as iris and it appears black as all light is reflected from it.

The aperture is known as the pupil and it appears black as no light is reflected from it.

Solution

Question 6

i-a,ii-b,iii-c,iv-d

i-d,ii-c,iii-b-iv-a

i-c,ii-b,iii-a,iv-d

i-b,ii-a,iii-c,iv-b

Solution

Question 7

i-c,ii-d,iii-a,iv-b

i-d,ii-c,iii-b,iv-a

i-b,ii-c,iii-a,iv-d

i-a,ii-b-iii-d,iv-c

Solution

Question 8

remains the same, decreases

increases, decreases

decreases, increases

increases, remains the same

Solution

Question 9

1-b, 2-c, 3-a, 4-d

1-d, 2-c, 3-b, 4-a

1-a, 2-c, 3-b, 4-d

1-c, 2-a, 3-d, 4-b

Solution

Question 10

$$25\ cm$$

Near point

Least distance of distinct vision

All of the above

Solution

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