1. Light is the most important tool of guidance.

Humans need light to see and go about daily activities. The invention of fire was man's attempt to substitute the light of the day while he fights the darkness of the night. Today, technological advancements allow people to exploit other beneficial uses of light such as solar power. The light from the sun is used to power many different devices around the world.

1. The power of light also fuels human spirituality. Light has long been man's companion during times of meditation and prayer.
   

2. Light is a means of communication. Beacons, lasers, reflective devices and flashlights of various types prove useful in the conveyance of messages. Light is part of daily life, and it is impossible to live without it.
   

3. Source of food.
   Plants and other autotrophs synthesize their own food materials by use of light. The light which falls on the leaves and other greenish surfaces on plants is trapped. This trapped energy is converted to reserve energy in the form of food by a process known a photosynthesis. And since man depends directly of indirectly on plants for food, light is important
   

4. Vision
   without light these eyes might be absolutely of no us . Because of light, the eyes can receive the image of the objects and send the information to the brain. From this visual information we comprehend the objects. Hence we can notice that in darkness we could see nothing. So light makes us able to see objects around. An argument is ongoing in the medical world that we use our brains to see not our eyes. Well, either way, we need light for both to function.
   

5. Signal system: Light is the key visible signals. We use light as traffic signals, navigation signals etc.

Even our TV remote use infra red light rays to give signal to Television.

Thus light which appears to be simple phenomenon of universe has divers use to humans and life on earth.