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Nature of light
Light has dual nature. It has particle nature and can show wave nature as well.
In this chapter we will study the wave nature of light.
Wave evidence of the light:
Light and radio signals all undergo reflection, refraction, and diffraction. This suggests that they travel as waves. For example:
1- Light reflects from mirrors like sound waves reflect from hard surfaces.
2- Light bends when it passes from air in to glass or water.
3- Light also exhibits the phenomenon of diffraction like sound waves.
4- Light spreads when it passes through tiny holes and slits. This suggests that light waves must have much shorter wavelength then sound.
5- Some radio signals can bend round very large obstacles such as hills. This suggests that radio waves must have long wavelengths.
Particle nature of light:
The following phenomenon explains the particle nature of light.
1 – Photoelectric effect
2 – Compton effect
3 – Pair production
(You are not studying the above articles which show the particle nature of light, in IGCSE Physics)
important features of light
Some important features of light are as under:
1- Light is a form of radiation.
2- Light travels in straight lines.
3- Light transfers energy.
4- Light travels as waves.
5- Light can travel through empty space.
6- Light is the fastest thing there is.
7- Light has visible and invisible region.