A. Choose the correct option.
1.This is source of light.
a. Book b. Chair c. Bulb d. Metal key
Answer: c. Bulb
2.This is a natural source of light.
a. Bulb b. Sun c. Candle d. Lamp
Answer: b. Sun
3. Which of these materials is transparent?
a. Frosted glass b. Clear glass c. Smoked glass d. Coloured glass.
Answer: b. Clear glass
4.What is the nature of the image formed in a pin-hole camera?
a. Upright b. Inverted c. Erect d. None of these.
Answer: b. Inverted
5.Diffused reflection is produced by a
a. mirror b. rough wall c. polished metal surface d. none of these
Answer: b. Rough wall
B. Write T for true and F for false.
1. A street light is a natural source of light.
Answer:A street light is a natural source of light. — F
2.An object that emits light of its own is called a source of light.
Answer: An object that emits light of its own is called a source of light. — T
3.When we look through a transparent material, we can see all objects behind it clearly.
Answer: When we look through a transparent material, we can see all objects behind it clearly. — T
4.A pinhole camera produces a pin-sized image.
Answer: A pinhole camera produces a pin-sized image. — F
5. Reflection from a smooth surface is called diffused reflection.
Answer: Reflection from a smooth surface is called diffused reflection. — F
C. Match the following
| Column A | Column B |
| 1.Wood | a. Dark |
| 2.Frosted glass | b. Artificial source of light |
| 3.Candle flame | c. Natural source of light |
| 4. Star | d. Opaque |
| 5. Shadow | e. Translucent |
| Column A | Column B |
| 1.Wood | d. Opaque |
| 2.Frosted glass | e. Translucent |
| 3.Candle flame | c. Artificial source of light |
| 4. Star | d. Natural source of light |
| 5. Shadow | a.Dark |
D. Answer the following.
1.What are source of light? Give two examples each of natural and man-made sources of light.
Answer: A source of light is something that produces its own light.
- Natural sources: Sun, Stars
- Man-made sources: Bulb, Candle
2.Explain giving examples how materials are classified as transparent, translucent, and opaque.
Answer: Transparent materials let all light pass through, so we can see clearly through them. Example: Clear glass.
Translucent materials allow some light to pass through, but we cannot see clearly. Example: Frosted glass.
Opaque materials do not allow any light to pass through, so we can’t see through them. Example: Wood.
3.What is pin -hole camera? What kind of image does it form? Explain with diagram.
Answer: A pinhole camera is a simple camera without a lens that has a small hole for light to enter. It forms an inverted (upside-down) image of the object.
4. How is shadow formed? What are its characteristics?
Answer: A shadow forms when an opaque object blocks light from a source. The shadow is dark and has the shape of the object that blocks the light. Shadows can change in size and shape depending on the distance and angle of the light source.
5. Why is that we can see images on smooth surfaces and not on rough surfaces?
Answer: Smooth surfaces reflect light evenly, allowing us to see clear images. Rough surfaces scatter light in many directions, so we cannot see a clear image.
6.List the difference between an image and a shadow. Using an example of a book, write down two differences that you would see in its image and the shadow.
Answer: Image: Shows colors and details of the book. An image in a mirror would show the book’s cover and colors.
Shadow: Only shows a dark outline. The shadow of the book on the ground would look black and have no details or color.