How does the eye change, in order to focus on near or distant objects?
the lens moves in or out
the retina moves in or smaller
the lens becomes thicker or thinner
the pupil becomes larger or smaller
A person cannot see the distant objects clearly(though he can see the nearby objects clearly). He is suffering from the defect of vision called:
hypermetropia
myopia
night blindness
cataract
The angle between an incident ray and the plane mirror is 300. The total angle between the incident ray and the reflected ray will be:
300
600
900
1200
As the angle between two plane mirrors is decreased gradually, the number of images of an object placed between them:
increases gradually
decreases gradually
first increases then decreases
first decreases then increases
An opaque object appears black when white light shines on it. It is because
No light is reflected
No light is absorbed
Red, blue and green light are all reflected
All the light has been transmitted through the object.
The deficiency of one of the following in the diet of a person for a considerable time can lead to a disease called night blindness. This one is:
vitamin B
vitamin D
vitamin A
vitamin C
Plane mirrors are arranged parallel to each other to get
A single image
Two images
A large number of reflected images
No image
The pupil in human eye can be dilated by :
Retina
Choroid
Optic nerve
Iris
The most comfortable distance at which one can read with a normal eye is about
25 cm
25 m
infinity
15 cm
The sun is seen before the actual sun rise because of
Reflection
Refraction
Scattering
Rectilinear propagation of light