Human Eye — Set 6
Physics · मानव नेत्र · Questions 51–60 of 60
The cornea is the transparent continuation of the?
Correct Answer: D. Sclera
The sclera is the tough outer coat of the eye. At the front, it continues as the transparent cornea. This continuity helps maintain the shape and protection of the eyeball.
The fovea region of the retina is characterized by?
Correct Answer: C. Mostly cones and almost no rods
The fovea is specialized for high-resolution vision. It contains a very high density of cones and very few rods. This supports sharp and detailed color vision in bright light.
Dilation of the pupil in dim light is commonly called?
Correct Answer: A. Mydriasis
In dim light, the pupil becomes larger to admit more light. This widening of the pupil is called mydriasis. The iris muscles control this change automatically.
Pupil dilation is mainly caused by contraction of the iris?
Correct Answer: D. Radial muscles
The iris has both circular and radial muscle fibers. Contraction of radial muscles pulls the pupil open to enlarge it. This helps more light enter in low illumination.
Conjunctiva is best described as a?
Correct Answer: D. Thin membrane lining eyelids and covering sclera
Conjunctiva is a thin, transparent membrane. It lines the eyelids and covers the sclera but not the cornea. It helps protect the eye and keeps the surface moist.
One key role of the vitreous humor is to?
Correct Answer: B. Help maintain the spherical shape of the eyeball
Vitreous humor fills the large space behind the lens. Its gel-like nature supports the retina and the overall eye shape. It also helps the eyeball keep a stable internal form.
The most common type of color vision deficiency generally involves difficulty with?
Correct Answer: B. Red–green discrimination
Many common color vision deficiencies affect red and green perception. This usually happens due to cone pigment differences. It is more common than blue–yellow type deficiencies.
The minimum angle that a normal human eye can typically resolve is about?
Correct Answer: D. 1 minute of arc
Resolving power describes how close two points can be and still be seen as separate. For a normal eye, the minimum resolvable angle is about 1 minute of arc. This limit relates to retinal spacing and diffraction effects.
The pupil of the eye is best described as?
Correct Answer: C. An aperture in the iris
The pupil is simply an opening in the iris. Light passes through this opening into the eye. Its diameter changes to regulate light entry.
The cornea is especially sensitive to touch mainly because it has?
Correct Answer: D. Many nerve endings
The cornea contains many sensory nerve endings. This makes it highly sensitive and protective against injury. Even small dust particles can trigger blinking due to this sensitivity.