Light - Introduction and it's Properties | Reflection , Refraction and Absorption of Light

Light is one of the most valuable things in our everyday life. Many questions can be asked from this chapter in exams. So let us understand first what is light.

What is Light?

Light is a form of energy that helps us to see objects.

Without Light, all colorful things would have been black for us.

 Types of Objects

There are two types of the object found:-

1. Luminous  objects
2. Non Luminous objects

Luminous Objects

Those objects which have their own light i.e. they make their own light. When their light comes to our eyes that is the moment when we can see them.

Examples:- Sun makes its own light, Bulb creates light using electricity. 

Non Luminous Objects

Those objects which do not have their own light are luminous objects. So to see them we need luminous objects around them.

Example:- Your book, furniture, pencil, moon, etc.

Properties of Light

1. Light tends to travel in a straight line.
2. Light has dual nature i.e. wave as well as a particle. Reflection, Refraction of light shows the wave nature of light. It shows how light bends around an object. Sometimes it behaves like a particle (called a photon), which explains how light travels in straight lines.
3. An electromagnetic wave so does not require any medium to travel.
4. The speed of light is maximum in the vacuum. Its value is 3 × 10⁸ m/s.
5. When light falls on the surface following may happen:-

• Reflection
• Refraction
• Absorption

Reflection of Light

Bouncing back of the light when it falls on the surface of an object is called Reflection of light. Silver is the best reflector of light.

Absorption of Light

Light falling on any surface may get absorbed. The body which surface absorb all light appears black in color. So black is a good absorber and emitter of light.

Why green surface appears green? 

You know that light is consists of seven colors. When it false on a surface some color of light gets absorbed and some not. So when it falls on a surface and absorbs all color except green then that surface appears green to us.

So you can tell me now Why the red surface appears red? 

Refraction of Light

Light falling on the surface may get pass-through it. It's not necessary that all rays would pass through the surface. Some objects allow all rays to pass, these objects are known as Transparent Objects. But few objects don't allow all rays to pass through it. Only few rays can oass through them. These objects are known as Translucent Objects.