10 Question-answer on human eye and camera
1. Near and far points of a healthy human eye respectively are
(a) 0 and 25 cm
(b) 0 and infinity
(c) 25 cm and 100 cm
(d) 25 cm and infinity
Ans: (d)
2. A person suffering from presbyopia should use
(a) A concave lens
(b) Convex lens
(c) A bifocal lens whose lower portion is convex
(d) A bifocal lens whose upper portion is convex
Ans: (c)
3. The focal length of concave lens required to correct myopia is:
(a) Less than the distance of far point from the eye
(b) Equal to the distance of far point from the eye
(c) Equal to 25 cms
(d) Equal to 125 cms
Ans: (b)
4. A defect of vision in which lines in one plane of an object appear in focus while those in another plane are out of focus is called
(a) Astigmatism
(b) Distortion
(c) Myopia
(d) Hypermetropia
Ans: (a)
5. A cylindrical lens is required to correct
(a) Myopia
(b) Presbyopia
(c) Hypermetropia
(d) Astigmatism
Ans: (d)
6. The sensitivity of eye varies with wave length of light. The eye is most sensitive with ordinary intensity in the
(a) Red light
(b) Blue light
(c) Yellow green region
(d) Red green region
Ans: (c)
7. The focal length of the lens in the human eye is maximum when it is looking at an object at
(a) Infinity
(b) 25 cms. From the eye
(c) 100 cms from the eye
(d) A very small distance from the eye.
Ans: (a)
8. A person cannot see objects clearly beyond 50 cm. the power of the lens to correct the vision is
(a) + 5 diopter
(b) 0.5 diopter
(c) -2 diopter
(d) +2 diopter
Ans: (c)
9. A far-sighted man cannot focus distantly on objects closer than 120 cm. the lens that will permit him to read from a distance of 40 cm will have a focal length
(a) + 30 cm
(b) – 30 cm
(c) +60 cm
(d) – 60 cm
Ans: (c)
10. The resolution limit of the eye is 1 minute. At a distance x km from the eye, two persons stand with a lateral separation of 3 km. for the two persons to be just resolved by the naked eye, x-should be
(a) 10 km
(b) 15 km
(c) 20 km
(d) 30 km
Ans: (a)