Class 10 The Human Eye and the Colourful World Questions

 📝Class 10  The Human Eye and the Colourful World  Questions 

1. In the diagram, the angle of incidence, the angle of emergence, and the angle of deviation respectively have been represented by 

(a) y, p and z

(b) x, q and z

(c) p, y and z

(d) p, z and y

Ans: (c)

2. 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?

(a) (i)

(b) (ii)

(c) (iii)

(d) (iv)

Ans: (b)

3. 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 the violet light

Ans: (c)

4. Out of all colours making the white light, which one will deviate the most while it passes through a prism?

(a) Red

(b) Violet

(c) Blue

(d) Green

Ans: (b)

5. In an experiment to trace the path of a ray of light through a triangular glass prism, a student would observe that emergent ray

(a) is parallel to the incident ray

(b) is along the same direction of the 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.

Ans: (d)

6. Which of the following statement is correct about constituents of white light?

(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 at different speeds in a vacuum.

Ans: (a)

7. 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

Ans: (a)

8. 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

Ans: (c)

9. 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

Ans: (b)

9. 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 lights of all other colours by the atmosphere

(d) light of all other colours is scattered more than the violet and blue colour lights by the atmosphere

Ans: (c)

10. 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 the violet light

Ans: (c)

11. 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

Ans: (b)

12. 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

Ans: (b)

13. 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

Ans: (c)

14. 1. A person cannot see distinctly objects kept beyond 2 m. This defect can be corrected by using a lens of power 

(a) + 0.5 D 

(b) – 0.5 D 

(c) + 0.2 D 

(d) – 0.2 D

15. A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his textbook. Which of the following statements is correct? 

(a) The near point of his eyes has receded away 

(b) The near point of his eyes has come closer to him 

(c) The far point of his eyes has come closer to him 

(d) The far point of his eyes has receded away

16. The focal length of the eye lens increases when eye muscles 

(a) are relaxed and lens becomes thinner 

(b) contract and lens becomes thicker 

(c) are relaxed and lens becomes thicker 

(d) contract and lens becomes thinner

17. Which of the following statement is correct? 

(a) A person with myopia can see distant objects clearly 

(b) A person with hypermetropia can see nearby objects clearly 

(c) A person with myopia can see nearby objects clearly 

(d) A person with hypermetropia cannot see distant objects clearly

 

★★★★★★

1. A student observes the above phenomenon in the lab as white light passes through a prism. Among many other colours, he observed the position of the two colours Red and Violet

 What is the phenomenon called? What is the reason for the violet light to bend more than the red light?

2. Draw ray diagrams each showing (i) myopic eye and (ii) hypermetropic eye.

3. A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.

4. A person needs a lens of power –4.5 D for correction of her vision. 

(a) What kind of defect in vision is she suffering from? 

(b) What is the focal length of the corrective lens? 

(c) What is the nature of the corrective lens?

5. When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?