The nature of light waves and analysis of white light
The light waves
The light is an external factor which affects the eye causing the sense of vision , The light waves are electromagnetic transverse waves which can travel through free space with velocity 300000 km / sec .
The light waves are formed of crests and troughs , and the speed of light is the distance covered by the light in one second , the light is electromagnetic radiation within a certain portion of the electromagnetic spectrum .
The visible light is one of the components of electromagnetic spectrum of wavelength ranges between 380 to 700 nanometres , It is between infrared ( with longer wavelenths ) and the ultraviolet ( with shorter wavelengths ) , infrared and ultraviolet are also called light .
Analysis of white light
Analysis of white light is the splitting of white light into seven colours called the spectrum colours , When the white light falls on a triangular glass prism , it analysis into seven spectrum colours and they have different wavelengths of the light .
The Sun is the main source of light energy on the Earth’s surface , and if you put a compact disc ( C D ) on a table such that its glistening surface faces the Sun rays ( a source of white light ) , you will observe the formation of seven colours .
The white light consists of a mixture of seven colours which are know as ” The spectrum colours ” , and these colours are Red – Orange – Yellow – Green – Blue – Indigo – Violet .
Red has the lowest deviation ( It is the closest to the prism apex ) , the lowest frequency , and the longest wavelength , Violet has the highest deviation ( it is the closest to the prism base ) , the highest frequency , and the shortest wavelength .
The energy of the photon of red light is smaller than the energy of the photon of violet light , because the energy of photon is directly proportional to the frequency .
The German scientist Max Plank proved in 1900 that the energy of light waves is composed of energy quanta known as ” photons ” , The energy of the photon ( E ) is directly proportional to the frequency of the light wave ( F ) .
The energy of the photon = Plank’s constant Χ Frequency of the photon .