# Light Energy | Sources, Examples & Facts

Light energy is a type of kinetic energy.

It was a fascinating thing for many scientists like Einstein, Faraday, Maxwell, etc.

Light is the only non-materialistic thing that is visible to the naked eye.

One can see, and feel it as the heat but cannot hold it and contain it as such.

It travels from one place to other in the form of light rays till it loses its energy. There are also many uses of light.

### Light energy facts:

1. Light is electromagnetic energy; it means, the light rays have both electric and magnetic behavior in them.

This electromagnetic radiation can be divided into different ranges based on wavelength or frequency.

This spectrum has gamma rays, X-rays, ultraviolet rays, visible rays, infrared radiation, microwaves, and radio waves in increasing order of wavelength.

2. Light Waves: Light travels in the form of waves. Each wave is characterized by its wavelength and frequency. Waves with greater energy have high frequency and small wavelengths. While waves with low energy have low frequency with long wavelengths. But interestingly they all travel at the same speed.

3. Speed of light: The speed of light is very high and maybe the fastest thing ever. In figures, it is 670,616,629 mph. And how could one calculate the speed of light and its history is interesting.

4. Light absorption: Light is absorbed by the substances it falls on. Most substances absorb the light rays to some extent and deflect the remaining. When the light is absorbed, heat is generated in most objects. Hence the floor or surfaces exposed to sunlight are hot.

A substance that absorbs all of the light rays or energy is called a black body. It is a hypothetical body and does not exist.

5. Photons of light: Light is thought to have energy packets called as photons. These are elementary particles of light and have a wave nature and particle nature. The energy of a photon is given by Planck’s constant i.e. E = hf. (Where ‘E’ =energy, ‘h’= Planck’s constant, and ‘f’= frequency of light).

6. Photosynthesis: When light falls on the green leaves of plants, they convert it into chemical energy which is stored as carbohydrates. Not only the sun, even if light from the electric bulbs at night falls on leaves, but photosynthesis also occurs.

7. Solar energy: The energy of light can be harvested by solar panels and used for domestic use. This alternative energy is environmentally friendly and so many started to harvest it.

Sources of light:

1. Sun: Sunlight is the oldest source of light energy. This sunlight is essential for life on earth as it has many uses like the water cycle, photosynthesis, sanitation, and sterilization. The energy of the sun is generated due to hydrogen fusion. This light travels from the sun around it and reaches the planets and other bodies around it including earth.

2. Electric bulbs: Electric bulbs are another source of this energy. When electricity flows through metallic filament tungsten in the bulb, it glows due to resistance. Due to resistance, the filament is so heated that it emits light.

3. Flame: When a fuel material is burnt, the flame produced emits light rays. So for night vision before the discovery of bulbs, lanterns, and other fire-emitting devices were used for illumination.

4. Explosions: When a powerful bomb is exploded, there is the emission of light due to intense heat generation. When atomic bombs were tested, the entire region was illuminated with intense light.
In the above examples, the energy of other forms like heat, and fission reaction is converted to energy of light.