Vidaara.orgClass 10 · Physics
CodeVID-P10-02-CH-01
The Human Eye and the Colourful World — Full Chapter Test
Name: ____________________
Roll No.: __________
Date: ____________
General Instructions
- This is a full-length test covering the whole chapter — every topic is included.
- All questions are compulsory.
- Section A carries 1 mark each, Section B 2 marks, Section C 3 marks and Section D 5 marks.
- Show all working and draw labelled diagrams where asked. Only final answers are given at the end — for full solutions, raise your doubts with your teacher.
Section A — Multiple Choice Questions
6 × 1 = 6 marks
1.
Most refraction of light entering the eye occurs at the
- A.retina
- B.cornea
- C.iris
- D.pupil
2.
Myopia is corrected by a
- A.convex lens
- B.concave lens
- C.plane mirror
- D.prism
3.
The unit of power of a lens is the
- A.metre
- B.dioptre
- C.watt
- D.newton
4.
Through a prism, the colour deviated the most is
- A.red
- B.yellow
- C.green
- D.violet
5.
The sky appears blue mainly due to
- A.dispersion
- B.scattering of blue light
- C.reflection
- D.total internal reflection
6.
The far point of a normal eye is at
- A.25 cm
- B.50 cm
- C.infinity
- D.1 m
Section B — Short Answer (2 marks)
4 × 2 = 8 marks
7.
Define the power of accommodation of the eye.
8.
Calculate the power of a concave lens of focal length 50 cm.
9.
State two causes of myopia.
10.
Why does the Sun appear red at sunset?
Section C — Short Answer (3 marks)
3 × 3 = 9 marks
11.
A myopic eye has a far point of 1 m. Find the focal length and power of the correcting lens.
12.
Explain dispersion of white light by a prism and name the order of colours.
13.
Differentiate between myopia and hypermetropia (image position and lens).
Section D — Long Answer (5 marks)
2 × 5 = 10 marks
14.
Draw a labelled diagram of the human eye and explain the function of cornea, iris, lens and retina.
15.
A hypermetropic person has a near point of 1 m. Find the power of the lens to read at 25 cm and explain the correction.
Answer Key
Section A — Multiple Choice Questions
- (B) cornea
- (B) concave lens
- (B) dioptre
- (D) violet
- (B) scattering of blue light
- (C) infinity
Section B — Short Answer (2 marks)
- Ability of the eye lens to change focal length to see near and distant objects clearly.
- $f=-0.5\,\text{m}$, $P=1/f=-2\,\text{D}$.
- Eyeball too long; eye lens too curved (focal length too short).
- Long atmospheric path scatters away blue, leaving mostly red light.
Section C — Short Answer (3 marks)
- $f=-1\,\text{m}$, $P=-1\,\text{D}$ (concave).
- Each colour bends differently; violet most, red least, giving VIBGYOR.
- Myopia: image in front of retina, concave lens; hypermetropia: image behind retina, convex lens.
Section D — Long Answer (5 marks)
- Cornea refracts light; iris controls pupil/light; lens fine-tunes focus; retina receives the real inverted image.
- $u=-0.25\,\text{m}$, $v=-1\,\text{m}$; $1/f=-1+4=3$; $P=+3\,\text{D}$ (convex lens).
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