Source of Light

The concept of light

Light is a form of energy that enables us to see. Without light, vision would not be possible as it is essential for our eyes to perceive objects. For an object to be visible, light must travel from the object to our eyes.

Sources of light

Sources of light can be classified into two categories:

1. Natural sources of light These sources emit light energy naturally without any external intervention. Examples:

   • The Sun
   • Stars
   

2. Artificial sources of light These sources emit light by transforming other forms of energy into light energy. Examples:

   • Electric bulbs
   • Fluorescent lamps
   • Candles
   • Kerosene lamps
   • Torches
   

Energy transformation examples:

• An electric lamp converts electrical energy into light energy.
• A torch transforms chemical energy stored in dry cells into light energy.

Distinction between luminous and non-luminous bodies

1. Luminous bodies These are objects that produce light energy on their own. Examples:

   • The Sun
   • Stars
   • Electric bulbs
   • Candles
   • Torches
   

2. Non-luminous bodies These are objects that do not produce their own light but are visible because they reflect light from luminous bodies. Examples:

   • The Moon (reflects sunlight)
   • Most everyday objects like furniture, walls, and clothing