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

Question: Which of the following phenomena contributes significantly to the reddish appearance of the sun at sunrise or sunset?
a) Dispersion of light
b) Scattering of light
c) Total internal reflection of light
d) Reflection of light from the earth
Answer: b

Question: The clear sky appears blue because
a) blue light gets absorbed in the atmosphere
b) ultraviolet radiations are absorbed in the atmosphere
c) violet and blue lights get scattered more than light of all other colours by the atmosphere
d) light of all other colours is scattered more than the violet and blue colour light by the atmosphere
Answer: c

Question: Which of the following statements is correct regarding the propagation of light of different colours of white light in air?
a) Red light moves fastest
b) Blue light moves faster than green light
c) All the colours of the white light move with the same speed
d) Yellow light moves with the mean speed as that of the red and violet light
Answer: c

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: In an experiment to trace the path of a ray of light through a triangular glass prism, the emergent ray
a) is parallel to the incident ray
b) is along the same direction of incident ray
c) gets deviated and bends towards the thinner part of the prism
d) gets deviated and bends towards the thicker part (base) of the prism
Answer: d

Question: Which of the following phenomena of light are involved in the formation of a rainbow?
a) Reflection, refraction and dispersion
b) Refraction, dispersion and total internal reflection
c) Refraction, dispersion and internal reflection
d) Dispersion, scattering and total internal reflection
Answer: c

Question: At noon the sun appears white as
a) light is least scattered
b) all the colours of the white light are scattered away
c) blue colour is scattered the most
d) red colour is scattered the most
Answer: a

Assertion And Reason Based MCQs :

Directions : In the following questions, A statement of Assertion (a) is followed by a statement of Reason (R). Mark the correct choice as.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is NOT the correct explanation of A.
(c) A is true but R is false.
(d) A is false and R is true.

Question: Assertion (A): Concave lens is used to correct myopia or short- sightedness.
Reason (R): A concave lens of suitable focal length diverges the parallel rays from the distant objects as if they are coming from the far point of the myopic eye. This helps the eye lens to form a clear image at the retina.
Answer: a

Question: Assertion (A): In case of rainbow, light at the inner surface of the water drop gets internally reflected.
Reason (R): The angle between the refracted ray and normal to the drop surface is greater than the critical angle.
Answer: a

Question: Assertion (A): Light from a distant object arriving at the eye lens may get converged at a point in front of the retina.
Reason (R): The eye is producing too much divergence in the incident beam.
Answer: c

Question: Assertion (A): A hypermetropic person prefers to remove his spectacles, while driving.
Reason (R): When a hypermetropic person wearing the spectacles looks at a distant object, the parallel rays from the distant object get converged in front of the retina. The image thus appears blurred.
Answer: a

Question: Assertion (A): Scattering of light is the reflection of light from an object in all directions.
Reason (R): The colour of scattered light depends on the size of scattering particles and wavelength of light.
Answer: b

Question: Assertion (A): A white light on passing through prism splits into its component colours as such that the red light emerges nearest to the base of the prism.
Reason (R): Wavelength of red light is more than other component colours and hence, red light deviates least.
Answer: d

Question: Assertion (A): Sunlight reaches us without dispersion in the form of white light and not as its components.
Reason (R): Dispersion takes place due to variation of refractive index for different wavelength but in vacuum the speed of light is independent of wavelength and hence vacuum is a non-dispersive medium.
Answer: a

Question: Assertion (A): Eye lens has the ability to focus clearly on the retina by adjusting its focal length.
Reason (R): This phenomenon is known as power of accommodation.
Answer: b

Case Based Questions :

Read the passage on human eye and answer any four questions from Eye is a natural optical device by which human could see objects around him. It forms an inverted, real image on a light sensitive surface. It works on the phenomenon of refraction of light through a natural convex lens. However, Meena was unable to see clearly the words written on the black board placed at a distance of approximately 3 m from her.
Her mother discussed the same with the doctor.
Doctor explained her about this defect of vision and its correction.

Question: The possible cause this defect is
a) eye ball is of same size
b) eye ball becomes long
c) eye ball becomes small
d) None of the above
Answer: b

Question: The closest distance up to which a person can see without any strain in the eyes
a) 35 cm
b) 15 cm
c) 5 cm
d) 25 cm
Answer: d

Question: The human eye forms the image of the object at its
a) Cornea
b) Iris
c) Pupil
d) Retina
Answer: d

Question: What kind of defect Meena is suffering from?
a) Myopia
b) Hypermetropia
c) Astigmatism
d) Malnutrition
Answer: a

A narrow beam of white light is passing through a glass prism as shown in the diagram. Study the diagram and answer any four questions from 

Question: Which of the following statement is correct about constituents of white light based on above observations?
a) White light consists of seven colours.
b) Violet colour suffers minimum deviation.
c) Red light suffers maximum deviation.
d) All the colours of the white light move with different speed in vacuum.
Answer: a

Question: Read the following statements carefully
(i) The prism behaves same as that of rectangular glass slab.
(ii) All the colours have different angles of deviation in case of dispersion through prism.
(iii) All the colours travel with the same speed of light in glass.
(iv) Dispersion of light is observed in case of rectangular glass slab.
Which of the above statement/s is true?
a) Only (ii)
b) (i) and (ii) only
c) (i), (ii) and (iv) only
d) All of the above
Answer: a

Question: The phenomenon observed in above set-up is
a) scattering of light
b) dispersion of light
c) reflection of light
d) refraction of light
Answer: b

Question: The cause of dispersion of light is
a) All the colors of light travel with the speed more than the speed of light.
b) All the colors have different angles of deviation.
c) All the colors do not travel with the same speed of light.
d) All the colors have the same wavelength.
Answer: c

Question: In nature, this phenomenon is observed in
a) Formation of rainbow
b) Twinkling of stars
c) Blue colour of sky
d) Advance sunrise
Answer: a

Read the given passage and answer any of the four questions from The human eyes gradually lose their power of accommodation. In such cases, the person cannot see distinctly and comfortably. There are three common eye defects, and they are myopia or nearsightedness, hypermetropia or far-sightedness, and Presbyopia. These defects are corrected by the use of suitable spherical lenses.

Question: An old person is unable to see clearly nearby objects as well as distant object. To correct the vision, what kind of lens will he require?
a) Concave lens
b) Bifocal lens whose upper portion is concave lens and lower portion is convex lens.
c) Convex lens
d) Bifocal lens whose upper portion is convex lens and lower portion is concave lens.
Answer: b

Question: An optician while testing the eyes of Mr. X found the vision to be 6/9. What does it mean?
By this he means that Mr. X
a) Can read the letters of 6 inches from a distance 9 m.
b) Can read the letters of 9 inches from 6 m.
c) Can read letters from 6 m which the normal eye can read from 9 m.
d) Can read letters from 9 m which the normal eye can read from 6 m
Answer: c

Question: A person cannot read newspaper placed nearer than 50 cm from his eyes. The defect of vision he is suffering from is
a) Myopia
b) Hypermetropia
c) Presbyopia
d) None of these
Answer: b

Question: This defect may be corrected using
a) Concave lens of focal length 25 cm.
b) Convex lens of focal length 50 cm.
c) Concave lens of focal length 50 cm.
d) Convex lens of focal length 25 cm
Answer: b