# Chapter 11: The Human Eye and the Colourful World

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## Chapter 11: The Human Eye and the Colourful World

Q1) A person went for a medical check-up and found that the curvature of his eye lens is increasing. Which defects is he likely to suffer from?

(a) myopia

(b) cataract

(c) presbyopia

(d) hypermetropia

Q2) A person gets out in the sunlight from a dark room. How does his pupil regulate and control the light entering in the eye?

(a) the size of the pupil will decrease, and less light will enter the eye

(b) the size of the pupil will decrease, and more light will enter the eye

(c) the size of the pupil will remain the same, but more light will enter the eye

(d) the size of the pupil will remain the same, but less light will enter the eye

Q3) When light rays enter the eye, most of the refraction occurs at the

(a) crystalline lens

(b) the outer surface of the cornea

(c) iris

(d) pupil

Q4) In which part of the human eye is the image of an object formed?

(a) iris

(b) pupil

(c) retina

(d) cornea

Q5) 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 the air

Q6) 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

Q7) A person is seeing an object closer to his eyes. What changes will take place in his eyes?

(a) the pupil size will expand

(b) the ciliary muscles will contract

(c) the focal length of the eye lens will increase

(d) the light entering in the eye will be more

Q8) The splitting of white light into different colours on passing through a prism is called

(a) reflection

(b) refraction

(c) dispersion

(d) deviation

Q9) The image shows a light ray incident on a glass prism.

The various angles are labelled in the image. Which angle shows the angle of incidence and angle of refraction, respectively?

(a) A and D

(b) B and E

(c) C and F

(d) D and F

Q10) The deflection of light by minute particles and molecules of the atmosphere in all directions is called ____________ of light.

(a) dispersion

(b) scattering

(c) interference

(d) Tyndall effect

Q11) 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

Q12) Why do stars appear to twinkle at night?

(a) because the light of stars travels in a different medium

(b) because the distance of a star varies when the earth rotates

(c) because the star changes its position relative to the earth

(d) because the atmosphere reflects the light at different angles

Q13) When white light enters a prism, it gets split into its constituent colours. This is due to

(a) different refractive index for the different wavelengths of each colour

(b) each colour has the same velocity in the prism

(c) prism material has high density

(d) Scattering of light

Q14) When white light enters a glass prism from the air, the angle of deviation is least for

(a) blue light

(b) yellow light

(c) violet light

(d) red light

Q15) Which option justifies that the Sun appears red at sunrise and sunset?

(a) red scatters highest by the atmosphere

(b) the distance between the sun and earth reduces

(c) red has a high wavelength, so it travels a longer distance

(d) the white light disperses into seven colours, only red enters the atmosphere

Q16) 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

Q17) 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

Q18) The image shows the dispersion of the white light in the prism.

What will be the colours of the X, Y and Z?

(a) X: red; Y: green; Z: violet

(b) X: violet; Y: green; Z: red

(c) X: green; Y: violet; Z: red

(d) X: red; Y: violet; Z: green

Q19) Which image shows the deviation of light in a prism?

(a)