Human Eye — Set 2
Physics · मानव नेत्र · Questions 11–20 of 60
Vitreous humor in the human eye is best described as?
Correct Answer: A. A jelly-like substance behind the lens
Vitreous humor is a clear, gel-like material. It fills the space behind the lens up to the retina. It helps the eye maintain its internal structure.
A myopic person has a far point of 2 m. What power of lens is needed to see distant objects clearly?
Correct Answer: B. -0.5 D
For distant objects, the image should form at the far point of the eye. Here v = -2 m and u ≈ -∞, so 1/f = 1/v - 1/u ≈ -1/2 - 0 = -0.5. Thus power P = 1/f = -0.5 D, which is a concave lens.
Hypermetropia (long-sightedness) is commonly associated with?
Correct Answer: A. An eyeball that is too short
Hypermetropia often occurs when the eyeball is shorter than normal. This makes near objects tend to focus behind the retina. A convex lens is used to help bring the focus forward.
A person can read clearly only beyond 50 cm. What power of lens helps them read at 25 cm?
Correct Answer: A. +2 D
To read at 25 cm, the lens should form a virtual image at the person’s near point of 50 cm. Using u = -0.25 m and v = -0.50 m, 1/f = 1/v - 1/u = -2 - (-4) = +2. So P = +2 D, meaning a convex lens is needed.
Cataract is a condition in which the?
Correct Answer: C. Eye lens becomes cloudy
Cataract occurs when the eye lens loses transparency. The cloudy lens scatters light and reduces clear vision. It is commonly associated with aging, though other causes exist.
Glaucoma is generally related to?
Correct Answer: B. Increased intraocular pressure that can damage the optic nerve
Glaucoma is linked to elevated pressure inside the eye. High pressure can harm the optic nerve over time. Early detection is important because damage may be irreversible.
Accommodation in the human eye is the ability to?
Correct Answer: A. Change the focal length of the eye lens
Accommodation is the eye’s ability to focus on objects at different distances. Ciliary muscles change the curvature of the lens to adjust focal length. This helps form a clear image on the retina.
The power of a lens in diopters (D) is defined as?
Correct Answer: D. Reciprocal of focal length in meters
Lens power measures how strongly a lens converges or diverges light. It is defined as P = 1/f when f is in meters. A shorter focal length means a higher power.
The range of vision of a human eye is the distance between the?
Correct Answer: D. Near point and far point
The eye can see clearly only within a certain distance range. This range is bounded by the near point and the far point. Outside this range, images do not focus properly on the retina.
The pupil appears black mainly because?
Correct Answer: B. Light entering it is mostly absorbed inside the eye
Light entering the pupil goes into the eye and is largely absorbed. Very little light is reflected straight back out. Therefore the pupil usually appears black.