CBSE Class 10 Science The Human Eye and the Colourful World MCQs Set B

Question : When an object moves towards a convex lens the size of image _____.
(a) Decreases
(b) Increases
(c) First decreases then increases
(d) Remains the same
Answer : D

Question : At a particular minimum value of angle of deviation, the refracted ray becomes :
(a) Parallel to base of prism
(b) Perpendicular to base of prism
(c) Inclined at 45degrees w.r.t base of prism
(d) None
Answer : A

Question : The image formed by retina of human eye is :
(a) Permanent
(b) temporary
(c) Blurred
(d) None
Answer : B

Question : Refraction of light by the earth’s atmosphere due to variation in air density is called
(a) atmospheric reflection
(b) atmospheric dispersion
(c) atmospheric scattering
(d) atmospheric refraction
Answer : D

Question : Twinkling of stars is due to atmospheric
(a) dispersion of light by water droplets
(b) refraction of light by different layers of varying refractive indices
(c) scattering of light by dust particles
(d) internal reflection of light by clouds.
Answer : B

Question : The muscular diaphragm that controls the sides of pupil is :
(a) Cornea
(b) Ciliary muscles
(c) Iris
(d) Retina
Answer : C

Question : The danger signals installed at the top of tall buildings are red in colour. These can be easily seen from a distance because among all other colours, the red light
(a) is scattered the most by smoke or fog.
(b) is scattered the least by smoke or fog.
(c) is absorbed the most by smoke or fog.
(d) moves fastest in air.
Answer : B

Question : Image formed in normal eye of human is:
(a) on retina
(b) beyond retina
(c) behind retina
(d) at infinity
Answer : A

Question : One cannot see through the fog, because
(a) refractive index of the fog is very high
(b) light suffers total reflection at droplets
(c) fog absorbs light
(d) light is scattered by the droplets
Answer : D

Fill in the Blank

Question. The ability of the eye to focus both near and distant objects, by adjusting its focal length, is called the ..........
Answer : Accommodation of the eye.

Question. .......... is the inside surface of the rear part of the eyeball where the light entering the eye is focused.
Answer : Retina

Question. The splitting of white light into its component colours is called ...........
Answer : Dispersion

Question. The defect of the eye due to which a person is unable to distinguish between certain colours, known as ..........
Answer : Colour blindness

Question. The smallest distance, at which the eye can see objects clearly without strain, is called the .......... of the eye.
Answer : Near point

Question. The eye which cannot simultaneously see with the same distinctness all objects or lines making different inclinations is said to suffer from ..........
Answer : Astigmatism.

Question. ..............causes the blue colour of sky and the reddening of the Sun at sunrise and sunset.
Answer : Scattering of light

Question. The middle point of the iris has a hole, which is called ..........
Answer : Pupil

Question. The eye which suffers from myopia as well as from hypermetropia is said to suffer from ..........
Answer : Presbyopia

True or False

Question. Clouds look white because water droplets of clouds scatter all colours of light equally.
Answer : True

Question. The sun is visible two minutes before the actual sunrise due to atmospheric refraction.
Answer : True

Question. Danger signal lights are red in colour.
Answer : True

Question. The colour of the scattered light does not depend on the size of the scattering particles.
Answer : False

Question. Colour blindness is a genetic disorder which occurs by inheritance.
Answer : True

Question. Water droplets act as tiny prism in the formation of rainbow.
Answer : True

Question. The part of human eye that determines the colour of a person’s eye is known as cornea.
Answer : False

Question. The eye which cannot see distant objects clearly is said to suffer from myopia.
Answer : True

Question. The focal length of a given lens depends on the surrounding medium.
Answer : True

Question. Te transparent spherical membrane covering the front of the eye is known as cornea.
Answer : True

Question. To see an object comfortably and distinctly, you must hold it at about 25 cm from the eyes.
Answer : True

Question. The angle between incident ray and emergent ray is called angle of deviation.
Answer : True

Question : The ability of the eye to adjust its focal length according to the distance of the object and intensity of light falling on it is called