LIGHT

• "I am certain that light consists of particles, or as I call them, corpuscles."

  Isaac Newton
• "I say light consists of waves, and I propose a simple geometrical construction which gives the correct result for reflection, refraction, diffraction, and interference."

  Christiaan Huygens
• Light is made up of tiny particles called 'corpuscles'.


  Corpuscular Theory of Light
• These particles (corpuscles) are perfectly elastic.

  Corpuscular Theory of Light
• The corpuscles are emitted from luminous sources such as Sun, candle, electric lamp, fire, glowing objects, bioluminescent animals, etc.

  Corpuscular Theory of Light
• The tiny particles (corpuscles) always travel in a straight line in all directions.

  Corpuscular Theory of Light
• Each particle (corpuscle) carries kinetic energy with it while moving.


  Corpuscular Theory of Light
• The corpuscles travel at high velocity.


  Corpuscular Theory of Light
• The corpuscles (light) would travel faster in the denser medium than in the rarer medium.

  Corpuscular Theory of Light
• The corpuscles can be of different sizes.

  Corpuscular Theory of Light
• Light is a perfectly elastic particle, travelling at a very high speed.
• As particle is reflected by a reflecting surface incident angle equals the reflected angle.

  Corpuscles move horizontally and vertically.

  Angle and Velocity will be equal.

  Concept of Reflection
• The angle of incidence is equal to the angle of reflection due to the repulsion between corpuscles and the reflecting surfaces.

  Law of Reflection
• virtual, erect, and same size as the original object

  Plane Mirror
• When the light hits the reflecting surfaces, rays of light seemingly intersect at some point.

  Image is created at the back of the mirror.

  Plane Mirror
• Commonly used in optical devices

  Spherical Mirrors
• curves inward away from the light source like the inside of the spoon

  light rays reflect back and converges toward a single location known as the focal point

  real and virtual images are formed

  automobile head lights, flash lights, solar furnaces, dentist mirrors, shaving and makeup mirrors

  Concave Mirror
• curves outward towards the light source like the back of the spoon

  light rays reflect and diverge outwards

  virtual upright, and smaller in size images

  rearview and sideview automobile mirrors, security mirrors, surveillance in hallways, sharp bends, and concealed entrances

  Convex mirror
• light reflected with the same angle from a smooth shiny metal or a calm body of water produces a regular reflection

  brighter, shinier, more glare, concentrated reflection

  specular reflection
• light reflected from in different angles from a rough surface like paper or wavy water surface

  scattered

  diffused reflection
• simply the bending of light as it enters from one medium to another

  Refraction
• Velocity of light particle is greater at denser medium/substance


  Concept of Refraction
• According to Newton, when corpuscles (light particles) approach the refracting surface, they are ATTRACTED near the surface. When they enter the denser medium from a rarer medium, their speed increases, changing their direction.

  Concept of Refraction
• The apparent depth of a fish under water which appears to be closer to the surface than they actually are, is a result of - of light at the interference of air and water.

  Refraction
• Mirage, a virtual image formed a result of - when light is travelling from cool air into warmer air. This explains why "wet spots" sometimes while travelling in a car during summer and small island with palm trees are seen in the middle of a desert. Similarly, sailors observed mirages of a ship were sometimes stretched in the vertical direction called "towering", and were sometimes compressed called "stooping."


  Refraction
• The twinkling of a star is due to atmospheric - of starlight. The atmospheric - occurs n a medium of gradually changing refractive index caused by turbulence of the air through which the light travels.

  Refraction
• White light isn't in a single entity; it is actually made of different colors, and different colors have different size or particle.

  process of white light splitting into its constituent colors

  Concept of Dispersion
• Formed by the dispersion of light, refraction, and total internal reflection from water droplets

  Each water droplet can as a reflecting, refracting surface such as a prism

  Rainbow
• Brighter colors, Red is in the Outer, located lower (reflection, refraction, dispersion)

  formed when a sunbeam is being refracted twice and reflected once by the droplet

  Primary Rainbow
• Fainter colors, Red is the inner, located higher (refraction, double reflection, dispersion)

  Auxiliary Rainbow; formed when light rays reflected twice are deviated

  Secondary Rainbow
• Wave as a natural light (transverse wave)


  Wave Theory of Light
• Light is a series of waves in all directions.


  Wave Theory of Light
• Each point on a wave front may be regarded as a new source of disturbance.

  Light refraction, based on the concept of the wave-like nature of light, held that the velocity of light in any substance was inversely proportion to its refractive index.


  Wave Theory of Light
• a vibration or disturbance in space

  Wave
• requires a medium


  Mechanical Waves
• do not require a medium (light, microwaves, infrared, x-rays, ultraviolet rays, radio waves)

  Electromagnetic Waves
• particles of the medium move PARALLEL to the wave's direction of travel; sound waves


  Longitudinal Wave
• the height of a wave from the middle line to the crest or the trough

  Amplitude
• the bottom of the wave

  Trough
• the top of the wave

  Crest