A person wears glasses of power – 2.5 D. The defect of the eye and the far point of the person without the glasses are respectively ____.
farsightedness, 40 cm
nearsightedness, 40 cm
astigmatism, 40 cm
nearsightedness, 250 cm
Myopia is due to ____.
elongation of eye ball
irregular change in focal length
shortening of eye ball
older age
A person is suffering from the defect astigmatism. Its main reason is ____.
distance of the eye lens from retina is increased
distance of the eye lens from retina is decreased
the cornea is not spherical
power of accommodation of the eye is decreased
A person cannot see objects clearly beyond 2.0 m. The power of lens required to correct his vision is ____.
+ 2.0 D
– 1.0 D
+ 1.0 D
– 0.5 D
The resolving limit of healthy eye is about ____.
When objects at different distances are seen by the eye, which of the following remains constant?
the focal length of the eye lens
the object distance from the eye lens
the radii of curvature of the eye lens
the image distance from the eye lens
A person wears glasses of power – 2.0 D. The defect of the eye and the far point of the person without the glasses is ____.
nearsighted, 50 cm
farsighted, 50 cm
nearsighted, 250 cm
astigmatism, 50 cm
An eye specialist prescribes spectacles having a combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm. The power of this lens combination in diopters is ____.
+ 1.5
– 1.5
+ 6.67
– 6.67
Near and far points of a human eye are ____.
0 and 25 cm
0 and (
25 cm and 100 cm
25 cm and (
Two parallel pillars are 11 km away from an observer. The minimum distance between the pillars so that they can be seen separately is ____.
3.2 m
20.8 m
91.5 m
183 m
Retina of eye acts like ____ of camera.
shutter
film
lens
None of the above
The hyper-metropia is a ____.
short-side defect
long- side defect
bad vision due to old age
None of the above
Amount of light entering into the camera depends upon ____.
focal length of the objective lens
product of focal length and diameter of the objective lens
distance of the object from camera
aperture setting of the camera
A man cannot see clearly the objects beyond a distance of 20 cm from his eyes. To see distant objects clearly he must use which kind of lenses and of what focal length ____.
100 cm convex
100 cm concave
20 cm convex
20 cm concave
A person uses spectacles of power +2D. He is suffering from ____.
Short sightedness or myopia
Long sightedness or Hypermetropia
Presbyopia
Astigmatism