LIGHT: A WAVE OR A PARTICLE

• Two types of light sources - incandescent sources and luminous sources
• Incandescent sources - uses heat to produce light
• luminous sources - normally cooler and can be produce by chemical reactions
• waves - it is the disturbances propagating in a medium or a vacuum, carrying the energy with them
• types of wave based on the medium - mechanical waves and electromagnetic waves
• types of wave based on the direction - transverse waves and longitudinal waves
• Mechanical waves- waves that need a medium to propagate
• electromagnetic waves - waves that propagate in a vacuum
• transverse waves - waves where the particles of the medium vibrate perpendicularly to the direction of wave propagation

  
• longitudinal waves - waves where the particles of the medium vibrate parallel to the direction of wave propagation

  
• Wave theory - it is proposed by a Dutch scientist Christian Huygens
• Christian Huygens - he compared light with sound waves
• Wave theory - the light is a longitudinal wave propagating in all directions at constant velocity in homogenous medium
• Corpuscular theory - theory proposed by Isaac Newton
• Corpuscular theory - the light consists of tiny particles or corpuscles coming from a luminous object, the color of each object differs depending on the size and mass of it
• Electromagnetic theory - proposed by Scottish scientist James Clerk Maxwell
• electromagnetic theory - light is a transverse wave having electrical and magnetic properties
• Quantum theory - theory that is proposed by Max Planck
• Quantum Theory - it is a theory where the light is emitted in discrete packets of energy called quanta of energy but Albert Einstein referred to this as photon
• the light has a dual nature which is as a particle and a wave
• Prism - a piece of glass that allows light to pass through and separates it into component colors
• Dispersion of light - it is the phenomena wherein visible light is being separated into its component colors
• Reflection - the phenomena wherein the light is turning back to the original medium from where it is has been traveling after hitting a surface
• Incident ray - ray that strikes the surface
• reflected ray - ray that rebounds on the surface
• angle of incidence - what angle is between incident ray and the normal
• angle of reflection - what is the angle between the reflected ray and the normal
• specular reflection - light reflected from a smooth surface
• diffuse reflection - light reflected from rough surface
• refraction - the phenomenon where there is a change in the speed of light when it passes from one medium to another
• Snell's law - the angle of incidence is equal to the angle of refraction