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

Question: Which option justifies that the sun appears red at sunrise and sunset?
a) The distance between the sun and earth reduces.
b) The white light disperses into seven colours, only red enters the atmosphere.
c) Red has high wavelength, so it travels longer distance.
d) Red scatters highest by the atmosphere.
Answer: c

Question: The angle at which the ray gets deviated is called
a) Angle of deviation
b) Angle of dispersion
c) Angle of emergence
d) Refracted angle
Answer: a

Question: A transparent refracting material which is bounded by two plane refracting surfaces is
a) Prism
b) Convex lens
c) Glass slab
d) None
Answer: a

Question: Red colour of the sun at the time of sunrise and sunset is because–
a) Red colour is least scattered
b) Blue colour is least scattered
c) Red colour is scattered the most
d) All colours are equally scattered
Answer: a

Question: The angle between two refracting surfaces of a prism is called the angle of
a) Prism
b) Emergence
c) Deviation
d) Incidence
Answer: a

Question: When Newton colour disc is rotated fast, the different colours ________.
a) Can be separated
b) Can be differentiated
c) Cannot be differentiated
d) None
Answer: c

Question: The sun appears two minutes before the actual sunrise due to atmospheric refraction. How does sunlight travel from space to atmosphere?

Answer: b

Question: The effect of glass prism is only to separate the seven colours of
a) White light
b) Light from bulb
c) Sunlight
d) All
Answer: d

Question: A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white light is incident on the prism as shown in figure. In which of the following cases, after dispersion, the third colour from the top corresponds to the colour of the sky?

Answer: b

Question: Which of the following is a natural phenomenon which is caused by the dispersion of sunlight in the sky?
a) Twinkling of stars
b) Stars seem higher than they actually are
c) Advanced sunrise and delayed sunset
d) Rainbow
Answer: d

Question: For which colour, refractive index of glass is maximum?
a) Red
b) Violet
c) Green
d) Yellow
Answer: b

Question: White light passes through an equilateral prism then
a) dispersion takes place at first refracting surface and refraction at second refracting surface
b) refraction takes place at first refracting surface and refraction at second refracting surface
c) dispersion takes place at both refracting surfaces
d) refraction takes place at both refracting surfaces
Answer: a

Question: The broad wavelength range of visible spectrum is
a) 4000–8000 Å
b) 2000–4000 Å
c) 10000–20000 Å
d) None of the above
Answer: a

Question: The splitting of white light into different colours on passing through a prism is called
a) Reflection
b) Refraction
c) Dispersion
d) Deviation
Answer: c

Question: The _________ colour is at the top and _________ colour is at the bottom of spectrum.
a) Red, Violet
b) Red, Blue
c) Violet, Red
d) None
Answer: a

Question: Which of the following is correct for the order of colours present in white light
a) VIBGYOR
b) VIYGOBR
c) VBIYORG
d) VIGBOYR
Answer: b

Question: Name the scientist who was the first to use a glass prism to obtain the spectrum of sunlight.
a) Isaac Newton
b) Einstein
c) Kepler
d) Hans Christian Oersted
Answer: a

Question: The bluish colour of water in deep sea is due to
a) The presence of algae and other plants found in water
b) Reflection of sky in water
c) Scattering of light
d) Absorption of light by the sea
Answer: c

Question: When a beam of white light passes through the prism
a) Velocity of violet rays is greater than that of red rays
b) Velocities of violet and red rays are equal to each other
c) Velocity of violet rays is smaller than that of red rays
d) Velocities of violet and red rays do not change
Answer: c

Question: What is the name of:
(a) the curved, transparent front surface of the eye?
(b) the light-sensitive layer in the eye?
Answer: (a) Cornea (b) Retina

Question: How much is our field of view:
(a) with one eye open?
(b) with both eyes open?
Answer: (a) About 150° (b) About 180°

Question: A student sitting in the last row of the class-room is not able to read clearly the writing on the blackboard.
(a) Name the type of defect he is suffering from.
(b) How can this defect be corrected?
Answer:
(a) Myopia (Short-sightedness)
(b) Concave lens

Question: What is the colour of the sunlight:
(a) scattered by the dust particles in the atmosphere?
(b) scattered by the air molecules in the atmosphere?
Answer: (a) White (b) Blue

Question: A man can read the number of a distant bus clearly but he finds difficulty in reading a book.
(a) From which defect of the eye is he suffering?
(b) What type of spectacle lens should he use to correct the defect?
Answer:
(a) Hypermetropia (Long-sightedness)
(b) Convex lens

Question: In the formation of spectrum of white light by a prism:
(i) Which colour is deviated least?
(ii) Which colour is deviated most?
Answer: (i) Red (ii) Violet

Fill in the following blanks with suitable words :

Question: When a ray of light enters a prism, it bends……………..the normal ; as it leaves the prism, it bends ………… the normal.
Answer: towards ; away from

Question: White light is composed of………….colours. The colour of white light deviated through the largest angle by a prism is…………..
Answer: seven; violet

Question: We can see the sun about………….minutes before the actual sunrise and about………….minutes after the actual sunset because of atmospheric……………
Answer: two ; two ; refraction

Question: Having two eyes gives a …………….field of view.
Answer: wider

Question: A short-sighted person cannot see ………….. objects clearly. Short-sightedness can be corrected by using ……………lenses.
Answer: distant ; concave

Question: A long-sighted person cannot see ………….. objects clearly. Long-sightedness can be corrected by using ………….. lenses.
Answer: nearby ; convex

Following questions consists of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
A. Both assertion and reason are true, and reason is the correct explanation of assertion.
B. Both assertion and reason are true, but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Assertion is false and reason is true.

Question: Assertion(A): The angle of incidence and the angle of emergence are equal.
Reason(R): The angle of refraction and the angle of deviation are not equal

Answer: b

Question: Assertion(A): Sun looks reddish at sunrise and sunset.
Reason (R) : Sun rays have to pass through smaller distance in atmosphere.

Answer: b

Question: Assertion: The path of light is visible due to scattering of light.
Reason : Tiny water droplets in the mist scatter light.

Answer: b

Question: Assertion(A): Rainbow is formed in the sky due to the dispersion of sunlight by water droplets.
Reason(R): Light of shorter wavelength is scattered much more than the light of longer wavelength.

Answer: b

Question: Assertion(A): The stars twinkle, while the planets do not.
Reason (R): The stars are much bigger in size than the planets.

Answer: b

Question: Assertion (A) : At Mid-day sun appears to be bright white .
Reason (R) : Scattering occurs due to size of dust particles and Air molecules.

Answer: a

Question: Assertion: Red light travels faster in glass than green light.
Reason: The refractive index of glass is less for green light

Answer: c