In CBSE Class 10 Science Paper, Students will have to answer some questions based on Assertion and Reason. There will be a few questions based on case studies and passage based as well. In that, a paragraph will be given, and then the MCQ questions based on it will be asked.
Here, we have provided case based/passage based questions for Class 10 Science Chapter 11 The Human Eye and The Colourful World.
Question 1:
Read the following and answer any four questions from (i) to (v).
The spreading of light by the air molecules is called scattering of light. The light having least wavelength scatters more. The sun appears red at sunrise and sunset, appearance of blue sky it is due to the scattering of light. The colour of the scattered light depends on the size of particles. The smaller the molecules in the atmosphere scatter smaller wavelengths of light. The amount of scattering of light depends on the wavelength of light. When light from sun enters the earth’s atmosphere, it gets scattered by the dust particles and air molecules present in the atmosphere. The path of sunlight entering in the dark room through a fine hole is seen because of scattering of the sun light by the dust particles present in its path inside the room.
(i) To an astronaut in a spaceship, the colour of earth appears
(a) red
(b) blue
(c) white
(d) black
Answer
Answer: (b) Light is scattered by the air molecules present in the atmosphere.(ii) At the time of sunrise and sunset, the light from sun has to travel.
(a) longest distance of atmosphere
(b) shortest distance of atmosphere
(c) both (a) and (b)
(d) can’t say
Answer
Answer: (a) As the distance between us and the sun is more at the time of sunrise and sunset.(iii) The colour of sky appears blue, it is due to the
(a) refraction of light through the atmosphere
(b) dispersion of light by air molecules
(c) scattering of light by air molecules
(d) all of these.
Answer
Answer: (c) Due to more scattering of blue colour by molecules of air.(iv) At the time of sunrise and sunset
(a) Blue colour scattered and red colour reaches our eye
(b) Red colour scattered and blue colour reaches our eye
(c) Green and blue scattered and orange reaches our eye
(d) None of these
Answer
Answer: (a) Red light being the largest wavelength blue scatters more, red scattered least.(v) The danger signs made red in colour, because
(a) the red light can be seen from farthest distance
(c) both (a) and (b)
(b) the scattering of red light is least
(d) none of these
Answer
Answer: (c) Scattering is least but velocity of red light is more.
Question 2:
Read the following and answer any four questions from (i) to (v)
Atmospheric refraction is the phenomenon of bending of light on passing through earth’s atmosphere. As we move above the surface of earth, density of air goes on decreasing. Local conditions like temperature etc. also affect the optical density of earth’s atmosphere. On account of atmospheric refraction, stars seen appear higher than they actual are; advanced sunrise; delayed sunset, oval appearance of the sun at sunrise and sunset; stars twinkle, planets do not.
(i) Due to atmospheric refraction, apparent length of the day
(a) increases
(b) decreases
(c) remains the same
(d) all of these
Answer
Answer: (a) Due to atmospheric refraction, apparent length of the day increases by 4 minutes.(ii) Apparent position of the star appears raised due to
(a) atmospheric refraction
(b) scattering of light
(c) both (a) and (b)
(d) none of these
Answer
Answer: (a) Apparent position of the stars appears raised due to atmospheric refraction.(iii) The sun appears oval shaped or flattened due to
(a) dispersion
(b) scattering
(c) atmospheric refraction
(d) cannot say
Answer
Answer: (c)(iv) Twinkling of stars and non-twinkling of planets is accounted for by
(a) scattering of light
(b) dispersion of light
(c) atmospheric refraction
(d) none of these
Answer
Answer: (c)(v) In absence of atmosphere, the colour of sky appears
(a) blue
(b) black
(c) red
(d) yellow
In absence of atmosphere, the colour of sky appears Black