science 2

• Predict the qualitative characteristics of images formed by plane and curved mirrors and lenses


  • Identify ways in which the properties of mirrors and lenses determine their use in optical instruments (e.g. cameras and binoculars)

  
• Particle (corpuscular) theory of light of Isaac Newton


  Light is made up of stream of particles (corpuscles)
• Wave theory of light of Christian Huygens


  Light is a wave and its production can be likened to the ripples produced in a pond of water when a stone is dropped in it
• Thomas Young's work on diffraction supported the wave theory of light
• James Clerk Maxwell classified light as an electromagnetic wave and calculated its speed
• Photoelectric effect of Heinrich Hertz

  When light hits a metal surface, some charges can be ejected from the metal. It is an instantaneous effect which cannot be explained plainly through Wave Theory of Light. This supports the Particle Theory.
• Quantum hypothesis of Max Planck

  Energy is quantized or discrete and that it is proportional to the frequency produced by the oscillation in a blackbody
• Quantum theory of light of Albert Einstein

  Light has both frequency and quanta of specific quantity, therefore, making it as both a wave and a particle
• The quantum theory of light is currently widely accepted by modern scientists
• Terms to use to describe the images from mirrors and lenses

  • Enlarged, Diminished or True (Same) Size
  • Upright versus Inverted
  • Real versus Virtual

  
• Mirror


  Something that is capable of producing image through reflection
• Reflection


  The bouncing of light back towards the direction of its origin as it hits a surface blocking its way
• Laws of reflection


  • θi = θr
  • IR, N, and RR always lie on same plane
• Regular or specular reflection


  It happens on a smooth surface – no significant irregularities in the form of bumps or indentions
• Irregular or diffused reflection


  It happens on a rough surface – with significant irregularities
• Plane mirror


  A mirror with flat surface
• Spherical mirror


  A mirror with curved surface; something that appears to have come from a sphere
• Concave mirror


  A spherical mirror with inward curve; converging the lights

  
• Convex mirror


  A spherical mirror with outward curve; diverging the lights

  
• Examples of mirrors per type

  • Plane: Usual mirrors in barbershops and restaurants
  • Concave: Mirror of compound light microscope; mirror of headlight
  • Convex: Rearview mirror, surveillance mirror in groceries
• Lens


  Something that is of a curved surface capable of producing image through refraction

  
• Refraction


  The change in the direction of light as it moves from one medium to another medium
• Index of refraction (n)

  A number that describes how fast an object travels through a material. It can be mathematically described as c/v, where c = speed of light in a vacuum and v = speed of light in a medium.
• The slower the light in a substance, the lower the "v," the lower the denominator in n=c/v, thus, the higher the "n"
• The faster the light in a substance, the higher the "v," the higher the denominator in n=c/v, thus, the lower the "n"
• Table of index of refraction (n)

  • Vacuum: 1.0000
  • Air: 1.0003
  • Solid Water: 1.3090
  • Liquid Water: 1.3300
  • Quartz: 1.4600
  • Immersion Oil: 1.5100
  • Glass: 1.5230
  • Sapphire: 1.7700
  • Zirconium: 2.2000
  • Diamond: 2.4190
• Laws of refraction


  • IR, N, and RR are always on same plane
  • The degree of change in direction of light relative to the normal (N) can be predicted based on difference in index of refraction (n)
  • Willebrord Snell's Law: n1 sin θi = n2 sin θr
• Concave lens


  A lens that has surface that curves inward; diverging the light

  
• Convex lens


  A lens that has surface that curves inward; converging the light

  
• Concave lenses


  • Thicker edges, thinner center
• Convex lenses


  • Thinner edges, thicker center

  
• Examples of lenses per major type

  • Concave Lens: Nearsighted eyeglass lens
  • Convex Lens: Eye lens; farsighted eyeglass lens; microscope lenses

  
• Spherical aberration: Rays that are far from the principal axis do not converge to a single point
• Spherical aberration can be corrected with parabolic mirrors
• Lenses: 3 special rays

  • An incident ray parallel to the principal axis results to an (actual/extended) refracted ray passing through the focus.
  • An (actual/extended) incident ray passing through the focus results to a refracted ray parallel to the principal axis.
  • A incident ray that passes through the center of the lens will remain unrefracted.

  
• Virtual


  Diminished, Upright
• Mirrors at Work
• Spherical Aberration


  • Rays that are far from the principal axis do not converge to a single point
  • The fact that a spherical mirror does not bring all parallel rays to a single point is known as spherical aberration
• Parabolic Mirror


  Can correct spherical aberration

  
• Lenses: 3 Special Rays