10.THE HUMAN EYE & WORLD-MCQ’S-1

What is the approximate diameter of the eyeball given in the chapter? What is the approximate diameter of the eyeball given in the chapter?

1 Mark(s)

1.3 cm 1.3 cm
3.8 cm 3.8 cm
2.3 cm 2.3 cm
5.2 cm 5.2 cm

What happens to light-sensitive cells in the retina when illuminated? What happens to light-sensitive cells in the retina when illuminated?

1 Mark(s)

They generate electrical signals They generate electrical signals
They become opaque They become opaque
They contract the iris They contract the iris
They increase the focal length They increase the focal length

When the ciliary muscles are relaxed, what happens to focal length? When the ciliary muscles are relaxed, what happens to focal length?

1 Mark(s)

It decreases It decreases
It becomes zero It becomes zero
It remains fixed It remains fixed
It increases It increases

Why can the focal length of the eye lens not be decreased below a certain limit? Why can the focal length of the eye lens not be decreased below a certain limit?

1 Mark(s)

The retina stops receiving light The retina stops receiving light
The cornea becomes opaque The cornea becomes opaque
The lens has a minimum focal-length limit
The optic nerve blocks light The optic nerve blocks light

What condition makes an old person's crystalline lens milky and cloudy? What condition makes an old person's crystalline lens milky and cloudy?

1 Mark(s)

myopia myopia
hypermetropia hypermetropia
dispersion dispersion
cataract cataract

What happens to the focal length when the eye lens becomes thicker for near vision? What happens to the focal length when the eye lens becomes thicker for near vision?

1 Mark(s)

It increases It increases
It becomes infinite It becomes infinite
It decreases It decreases
It does not change It does not change

What is the human eye compared with in the chapter? What is the human eye compared with in the chapter?

1 Mark(s)

a camera a camera
a telescope a telescope
a microscope a microscope
a periscope a periscope

Why may a very close printed page appear blurred to a normal eye? Why may a very close printed page appear blurred to a normal eye?

1 Mark(s)

The retina stops working The retina stops working
The eye cannot reduce focal length below its minimum limit
The cornea becomes opaque instantly The cornea becomes opaque instantly
The pupil becomes a lens The pupil becomes a lens

What happens to ciliary muscles when looking at a nearby object? What happens to ciliary muscles when looking at a nearby object?

1 Mark(s)

They relax completely They relax completely
They contract They contract
They become rigid and inactive They become rigid and inactive
They disappear They disappear

Which structure is a dark muscular diaphragm behind the cornea? Which structure is a dark muscular diaphragm behind the cornea?

1 Mark(s)

retina retina
iris iris
cornea cornea
optic nerve optic nerve

Which muscles modify the curvature of the eye lens? Which muscles modify the curvature of the eye lens?

1 Mark(s)

optic nerves optic nerves
ciliary muscles ciliary muscles
retinal cells retinal cells
iris muscles iris muscles

Which three refractive defects are listed as common in the chapter? Which three refractive defects are listed as common in the chapter?

1 Mark(s)

Cataract, rainbow and dispersion Cataract, rainbow and dispersion
Tyndall effect, myopia and cataract Tyndall effect, myopia and cataract
Myopia, hypermetropia and presbyopia Myopia, hypermetropia and presbyopia
Astigmatism, cataract and presbyopia Astigmatism, cataract and presbyopia

What is the main optical role of the crystalline lens according to the chapter? What is the main optical role of the crystalline lens according to the chapter?

1 Mark(s)

To control the amount of light To control the amount of light
To detect light To detect light
To provide finer adjustment of focal length
To transmit signals to the brain To transmit signals to the brain

What does the pupil regulate? What does the pupil regulate?

1 Mark(s)

The colour of the sky The colour of the sky
The focal length of the cornea The focal length of the cornea
The amount of light entering the eye The amount of light entering the eye
The electrical signals in the retina The electrical signals in the retina

What does the brain do with the signals received from the eye? What does the brain do with the signals received from the eye?

1 Mark(s)

It interprets and processes the information
It changes the lens curvature It changes the lens curvature
It controls atmospheric refraction It controls atmospheric refraction
It disperses white light It disperses white light

What is the least distance of distinct vision? What is the least distance of distinct vision?

1 Mark(s)

The minimum distance at which objects are seen clearly without strain
The farthest distance of clear vision The farthest distance of clear vision
The distance between the iris and retina
The distance to the optic nerve The distance to the optic nerve

What is the near point of a young adult with normal vision? What is the near point of a young adult with normal vision?

1 Mark(s)

About 2.5 cm About 2.5 cm
About 25 cm About 25 cm
About 25 m About 25 m
About 2.5 m About 2.5 m

Through which thin membrane does light enter the eye? Through which thin membrane does light enter the eye?

1 Mark(s)

iris iris
cornea cornea
retina retina
optic nerve optic nerve

What happens to the eye lens when ciliary muscles are relaxed? What happens to the eye lens when ciliary muscles are relaxed?

1 Mark(s)

It becomes thicker It becomes thicker
It becomes opaque It becomes opaque
It becomes spherical permanently It becomes spherical permanently
It becomes thin It becomes thin

Between which distances can a normal eye see clearly? Between which distances can a normal eye see clearly?

1 Mark(s)

25 cm and infinity 25 cm and infinity
2.5 cm and 25 cm 2.5 cm and 25 cm
80 cm and 1 m 80 cm and 1 m
0 cm and 25 cm 0 cm and 25 cm

Where does most refraction of incoming light occur in the eye? Where does most refraction of incoming light occur in the eye?

1 Mark(s)

At the retina At the retina
At the outer surface of the cornea At the outer surface of the cornea
At the optic nerve At the optic nerve
At the iris At the iris

What enables a normal eye to see distant objects clearly? What enables a normal eye to see distant objects clearly?

1 Mark(s)

A thicker lens with decreased focal length
A smaller pupil only A smaller pupil only
A cloudy lens A cloudy lens
A thinner eye lens with increased focal length

What is accommodation of the eye? What is accommodation of the eye?

1 Mark(s)

The ability to change eye colour The ability to change eye colour
The process of scattering light The process of scattering light
The ability of the eye lens to adjust its focal length
The formation of a rainbow The formation of a rainbow

What type of image does the eye lens form on the retina? What type of image does the eye lens form on the retina?

1 Mark(s)

An erect virtual image An erect virtual image
An inverted real image An inverted real image
An inverted virtual image An inverted virtual image
An erect real image An erect real image

What is the light-sensitive screen of the eye called? What is the light-sensitive screen of the eye called?

1 Mark(s)

iris iris
cornea cornea
pupil pupil
retina retina

What material is the eye lens composed of? What material is the eye lens composed of?

1 Mark(s)

Hard crystalline material Hard crystalline material
Liquid water only Liquid water only
Fibrous, jelly-like material Fibrous, jelly-like material
Muscular tissue Muscular tissue

How are signals from the retina sent to the brain? How are signals from the retina sent to the brain?

1 Mark(s)

Via the optic nerves Via the optic nerves
Via the cornea Via the cornea
Via the pupil Via the pupil
Via the ciliary muscles Via the ciliary muscles

How can vision affected by cataract be restored according to the chapter? How can vision affected by cataract be restored according to the chapter?

1 Mark(s)

Through a concave mirror Through a concave mirror
Through cataract surgery Through cataract surgery
By increasing pupil size permanently By increasing pupil size permanently
Through atmospheric refraction Through atmospheric refraction

What happens to the eye lens when ciliary muscles contract? What happens to the eye lens when ciliary muscles contract?

1 Mark(s)

It becomes thicker It becomes thicker
It becomes thinner It becomes thinner
It becomes transparent only at the edges
It becomes flat It becomes flat

What is the far point of a normal eye? What is the far point of a normal eye?

1 Mark(s)

25 cm 25 cm
Infinity Infinity
2.3 cm 2.3 cm
80 cm 80 cm

10.THE HUMAN EYE & WORLD-MCQ’S-1 : Question 1 of 30