10th LBA | Human Eye And Colourful World

MG SCHOOL SCIENCE

UNIT TEST QUESTION PAPER

CLASS 10 – SCIENCE

CHAPTER 10

The Human Eye and the Colourful World

Learning Outcome Based Assessment | 2026–27

Student Name

Class / Section

Date

Total Marks: 25

Questions: 15

Duration: 45 Minutes

Time: 45:00

GENERAL INSTRUCTIONS
1. All questions are compulsory.
2. Read each question carefully.
3. Draw neat and labelled diagrams wherever necessary.
4. Write scientific terms correctly.
5. Show all steps in numerical problems.
6. Marks are indicated against each section.

SECTION A – MULTIPLE CHOICE QUESTIONS (5 × 1 = 5 Marks)

1 Mark

1. The area where the image is formed in the human eye is:

A) Cornea B) Retina C) Iris D) Pupil

1 Mark

2. Which part of the eye forms an inverted real image on the retina?

A) Eye lens B) Pupil C) Iris D) Cornea

1 Mark

3. Which lens is used to correct near-sightedness (myopia)?

A) Convex lens B) Cylindrical lens C) Concave lens D) None of these

1 Mark

4. Clouding of the eye lens in old age is called:

A) Hypermetropia B) Myopia C) Presbyopia D) Cataract

1 Mark

5. Which structure controls the focal length of the eye lens?

A) Ciliary muscles B) Eyelid C) Retina D) Iris

SECTION B – ONE MARK QUESTIONS (4 × 1 = 4 Marks)

1 Mark 6. What is spectrum of white light?.

1 Mark 7. What is the far point of a normal human eye?

1 Mark 8. Define dispersion of light.

1 Mark 9. Name the three common defects of vision.

SECTION C – TWO MARK QUESTIONS (3 × 2 = 6 Marks)

2 Marks 10. What is hypermetropia? Mention its causes.

2 Marks 11. Write any two differences between myopia and hypermetropia.

2 Marks 12. Explain how the human eye lens adjusts itself to see nearby and distant objects.

SECTION D – THREE MARK QUESTIONS (2 × 3 = 6 Marks)

3 Marks 13. What is the Tyndall effect? Explain with two examples.

3 Marks 14. Why does the clear sky appear blue in colour? Explain scientifically.

SECTION E – FOUR MARK QUESTION (1 × 4 = 4 Marks)

4 Marks 15. Answer the following:

a) Explain the phenomenon of formation of a rainbow in the atmosphere. (2 Marks)

b) Why do stars twinkle? Explain. (2 Marks)

YOUR MCQ RESULT

0 / 5

Read the answer key below to check your answers.

📗 CLICK HERE – COMPLETE KEY ANSWERS (25 MARKS)

SECTION A – MCQ ANSWERS (5 Marks)

1. B) Retina – The image is formed on the retina.
2. A) Eye lens – The eye lens forms a real and inverted image on the retina.
3. C) Concave lens – It corrects myopia.
4. D) Cataract – Clouding of the eye lens is called cataract.
5. A) Ciliary muscles – They control the focal length of the eye lens.

SECTION B – ONE MARK ANSWERS (4 Marks)

6. What is spectrum of white light?
The band of the coloured components of a white light beam is called spectrum of white light.

7. What is the far point of a normal human eye?
The maximum distance up to which the eye can see objects clearly is called the far point. For a normal eye, it is infinity.

8. Define dispersion of light.
The splitting of white light into its constituent seven colours when it passes through a glass prism is called dispersion of light.

9. Name the three common defects of vision.
1. Myopia (near-sightedness).
2. Hypermetropia (far-sightedness).
3. Presbyopia.

SECTION C – TWO MARK ANSWERS (6 Marks)

10. What is hypermetropia? Mention its causes.

Hypermetropia is a defect of vision in which a person can see distant objects clearly but cannot see nearby objects distinctly. It is also called far-sightedness.

Causes:

1. The focal length of the eye lens is too long (its converging power is insufficient).
2. The eyeball is shorter than normal.

Correction: It is corrected using a suitable convex lens.

11. Write two differences between myopia and hypermetropia.

Myopia	Hypermetropia
Nearby objects are seen clearly, but distant objects are not.	Distant objects are seen clearly, but nearby objects are not.
Image of a distant object forms in front of the retina.	Image of a nearby object forms behind the retina.
Corrected using a concave lens.	Corrected using a convex lens.

12. Explain how the human eye lens adjusts itself to see nearby and distant objects.

For distant objects:

• Ciliary muscles relax.
• The eye lens becomes thin.
• The focal length increases.

For nearby objects:

• Ciliary muscles contract.
• The eye lens becomes thick.
• The focal length decreases.

SECTION D – THREE MARK ANSWERS (6 Marks)

13. What is the Tyndall effect? Explain with two examples.

The scattering of light by tiny particles in a colloid or in the atmosphere is called the Tyndall effect.

Examples:

1. The path of sunlight becomes visible when it enters a dense forest through the trees on a foggy morning.
2. The beam of light becomes visible when it passes through smoke or dust particles in a room.

14. Why does the clear sky appear blue in colour?

1. Air molecules and fine particles in the atmosphere scatter shorter wavelengths of sunlight more effectively than longer wavelengths.
2. Blue light is scattered much more strongly than red light.
3. The scattered blue light reaches our eyes from different directions, making the clear sky appear blue.

SECTION E – FOUR MARK ANSWER (4 Marks)

15(a). Explain the phenomenon of formation of a rainbow in the atmosphere. (2 Marks)

1. A rainbow is formed due to dispersion of sunlight by tiny water droplets present in the atmosphere.
2. The water droplets act like small prisms. Sunlight undergoes refraction and dispersion when it enters the droplets.
3. The light undergoes internal reflection inside the droplets.
4. It is refracted again when it emerges, producing the spectrum of colours (VIBGYOR).

15(b). Why do stars twinkle? (2 Marks)

1. Twinkling of stars is due to atmospheric refraction of starlight.
2. As starlight passes through atmospheric layers of changing refractive index, its apparent position and brightness fluctuate.
3. Consequently, the amount of light entering our eyes changes continuously, making stars appear to twinkle.

MARKS DISTRIBUTION

Section	Question Type	Marks
A	MCQ	5
B	One Mark	4
C	Two Marks	6
D	Three Marks	6
E	Four Marks	4
TOTAL		25

Teacher's Note: Award marks according to the relevant scientific points. Accept equivalent scientifically correct explanations.

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Class 10 Science | The Human Eye and the Colourful World