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The power of convex lens of focal length 20 cm is ______.
Concept: Power of a Lens
Observe the figure and answer the following questions:

- Name the defect of vision represented in the above figure.
- State the reasons for this defect.
- How is it corrected?
- Draw the diagram to show the correction of this defect.
Concept: Defects of Vision and Their Corrections > Myopia
Concept: Spherical Mirror > Concave Mirror
Concept: Spherical Mirror > Concave Mirror
Complete the following table by observing the given figures:
| Figure → | ![]() |
![]() |
| Points ↓ | ||
| (a) Name of the defect | ______ | ______ |
| (b) Position of the image | ______ | ______ |
| (c) Lens used to correct the defect | ______ | ______ |
Concept: Defects of Vision and Their Corrections > Myopia
When a ray of light travels from air to glass slab and strikes the surface of separation at 90°, then it …………….
(a) bends towards normal
(b) bends away from normal
(c) passes unbent
(d) passes in zigzag way
Concept: Refraction of Light Through a Rectangular Glass Block
Explain how spectrum is formed.
Concept: Refraction of Light Through a Rectangular Glass Block
When rays of light are incident on a glass slab then the incident ray and emergent ray are _________ each other.
- perpendicular
- parallel
- opposite
- concurrent
Concept: Refraction of Light Through a Rectangular Glass Block
What is a spectrum?
Concept: Refraction of Light Through a Rectangular Glass Block
Write a short note on dispersion of light.
Concept: Refraction of Light Through a Rectangular Glass Block
Define refraction and state the laws of refraction.
Concept: Refraction of Light Through a Rectangular Glass Block
| Column I | Column II | Column III | |
| 1 | Dispersion | Long-sightedness | Twinkling of stars |
| 2 | Refraction | Splitting of white light into component colours | Convex lens |
| 3 | Hypermetropia | Change in the direction of the ray of light due to change in medium | Spectrum of seven colours |
Concept: Refraction of Light
Explain how the formation of a rainbow occurs.
Concept: Refraction of Light Through a Rectangular Glass Block
Why do we get a spectrum of seven colors when white light is dispersed by a prism?
Concept: Refraction of Light Through a Rectangular Glass Block
Observe the following figure and answer the questions given under it:

1) How many times does refraction take place in the above figure?
2) What happens to the ray of light when it passes from air to glass?
3) What happens to the ray of light when it passes from glass to air?
4) What are the rays AB and CD in the figure called?
5) Define refraction.
Concept: Refraction of Light Through a Rectangular Glass Block
Observe the figure and write accurate conclusion regarding refraction of light.

Concept: Refraction of Light Through a Rectangular Glass Block
What is the correct reason for blinking / flickering of stars? Explain it.
a) The blasts in the stars.
b) Absorption of star light by the atmosphere.
c) Motion of the stars.
d) Changing refractive index of gases in the atmosphere.
Concept: Refraction of Light Through a Rectangular Glass Block
Choose and write the correct option.
If we gradually increase the angle of incidence of a ray of light passing through prism then …..
Concept: Refraction of Light
Choose the correct alternative and rewrite the following:
A glass slab is placed in the path of convergent light. The point of convergence of light
Concept: Refraction of Light Through a Rectangular Glass Block
The phenomenon of change in the direction of light when it passes from one transparent medium to another is called ___________.
Concept: Refraction of Light


