SAT II Subject Test Physics: Geometrical Optics - Some facts to remember

• Index of refraction of a medium
  n = (speed of light in air)/(speed of light in the given medium)
  
• If light goes through parallel surface of a transparent substance such as flat glass the emerging ray is parallel to the entering ray. The incident ray is refracted entering the glass bending towards the normal and then bending away from the normal when refracted again into the air. As a result the emerging ray is parallel to the enter ray.
  
• Rainbow colors we see in nature world and their optics characters

Infrared light has a greater wave length than red, ultraviolet has a shorter wavelength than violet, both not visible to human eyes, but used very commonly in industrial applications
• In vacuum all electromagnetic waves travel at the same speed
• If an object reflects no light, it is said to be black, if an object reflects all colors, it is show as white and if a white object exposed only to red light, it will appear as red. However on the other hand if a red color object is exposed by only blue light, it will show as black because the color of an opaque object is determined by the color of the light it reflects.
  
• Primary colors: Red, Green and Blue-violet
  If we mix two primary colors, we get the complementary color of the third one.
  
• Mixing primary color and its complementary color produces white color
  
  1. Red and blue-green
  2. yellow and blue-violet
  3. green and magenta (purple)
  The above is talking about color of light and don't get confused with mixing paint. Paint absord light and are seen as the color it reflects
• Resolving power of lenses
The imaging system's resolution can be limited either by aberration or by diffraction causing blurring of the image. A lens with a larger diameter will decrease the amount of the diffraction and increase the resolving power.
• Polarization
Polarized light is light whose direction of vibration has been restricted in some way. Please remember light is a transverse wave and only transverse wave can be polarized. Longitudinal wave can't be polarized.
• What is laser
Laser stands for "Light Amplification by Stimulated Emission of Radiation". Lasers are devices that produce monochromatic and coherent beams of light. The beam is very highly collimated (whose rays are nearly parallel, and therefore will spread slowly as it propagates), it has a very high energy density.
• Maxwell's theory
Light is transverse wave in which electric and magnetic fields vibrates or fluctuate at right angles to the direction of propagation.
• Doppler effect of light
We are all very familiar with doppler effect of sound waves. When the object that producing the sound wave is getting closer, the observed frequency is higher than the source. Doppler effect is common in all waves, just just sound. Light exhibits doppler effect as well even though it is much less noticed. LIDAR speed gun is an application that based on doppler effect of laser. I know all these science stuff are boring and people are making fun of it. If you like Physics, you probably watch "Big Bang Theory" and you certainly remember this one.

Or you can watch it on Youtube: You Tube.
• Explain why we can see a lot of colors with a thin film
This once again demonstrate the wave character of light.