There would be no world if lights were not there, as light provides us with the ability to see things. Plants also need light which is provided by the Sun to prepare their food and to grow. We can say that The Sun is the main source of light for Earth. Light comes from different sources, which are known as light sources. We can say that light is a form of electromagnetic radiation whose wavelength ranges from 380 – 700 nm, which is visible to the human eye. In the modern world, humans are also creating artificial light, which is the most suitable form of electrical energy.