Worksheet 11: Class 6 Science - Light, Shadows and Reflections

Welcome! This worksheet will help you understand the fascinating world of light and shadows. We will learn about how light travels, how shadows are formed, and how mirrors work. Let's explore the science of sight!

Light and Its Properties

We can see objects because of **light**. A substance that gives out its own light is called a **luminous object** (e.g., the sun, a light bulb). An object that does not give out its own light is a **non-luminous object** (e.g., a chair, a table). Light travels in a **straight line**.

Objects are classified based on how light passes through them:

• **Opaque Objects:** These objects block light completely and do not allow it to pass through. Wood, stones, and cardboard are examples of opaque objects.
• **Transparent Objects:** These objects allow all the light to pass through them. You can see clearly through transparent objects like glass or clear plastic.
• **Translucent Objects:** These objects allow some light to pass through, but you cannot see clearly through them. Examples include frosted glass and butter paper.

Shadows and Reflections

When an **opaque object** blocks the path of light, a dark patch called a **shadow** is formed behind it. A shadow requires a light source, an opaque object, and a screen (or surface) to be formed.

A **pinhole camera** is a simple device that shows how light travels in a straight line. The image formed by a pinhole camera is upside-down.

**Reflection** is the process of light bouncing off a surface. A mirror is a good reflector of light. When light hits a mirror, it bounces off and enters our eyes, allowing us to see an image. The image formed by a plane mirror is always virtual, erect (upright), and of the same size as the object.

Practice Questions

1. Fill in the blank: Light always travels in a _____ line.

Straight

2. True or False: A transparent object forms a dark shadow.

False. Only an opaque object forms a dark shadow. Transparent objects allow light to pass through completely.

3. Match the object to its property:

(a) A glass sheet (i) Opaque

(b) A brick (ii) Translucent

(c) Butter paper (iii) Transparent

a - iii, b - i, c - ii

4. What three things are required to form a shadow?

A light source, an opaque object, and a screen or surface.

5. Fill in the blank: A person's reflection in a mirror is an example of _____.

Reflection

6. Why does a pinhole camera form an inverted (upside-down) image?

Light travels in a straight line. The rays of light from the top of the object travel downwards through the pinhole to form the bottom of the image, and the rays from the bottom of the object travel upwards through the pinhole to form the top of the image.

7. Name two luminous and two non-luminous objects.

**Luminous:** Sun, candle flame. **Non-luminous:** Book, chair.

8. What is the difference between a transparent and a translucent object?

A **transparent** object allows light to pass through completely, and you can see clearly through it. A **translucent** object allows only some light to pass through, and you cannot see clearly through it.