SAT II Subject Test Physics: Geometrical Optics - Reflection and Refraction: Concepts

We started our notes with this only because my son learned very little at school on this subject and he felt least confident on this in the exam.

If you have read through the text in both "Princeton Review" and Barron's book on this topic, you should be familiar with the key words or terminologies listed below. If you are a parent, you can test your son or daughter's understanding by asking, e.g. "what is the angle of incident?". You can even ask him/her to draw on the paper. Without knowing the accurate definition of these terms, answering the questions can become tricky even if you do understand the concept.

1. Normal
The normal is a line perpendicular to the interface, the surface boundary of two medium

2. Angle of Incidence
The angle that the incident beam makes with the normal

3. Angle of Reflection
The angle that the reflected beam makes with the normal

4. Angle of Refraction
The angle that the transmitted (refracted) beam into the new medium makes with the normal

5. Diffraction
When a wave encounters a slit with a width that is comparable with the wavelength, the wave will fan out after it passes through Single slit and double slits experiments are used to demonstrate that light has wave characters.
6. diffraction gratings
Barriers that contain thousands of tiny slits per inch
7. Plane mirror
Flat mirrors are called plane mirrors
8. Law of reflection
Angle of incidence = Angle of reflection
9. Snell's Law

10. Regular reflection
11. Diffuse reflection
12. Virtual image (mirror and lens)
If the image is formed by the extension of the rays of light, the image is virtual
13. Real image (mirror and lens)
If the rays of light actually focus at the image, the image is said to be real. A real image can be projected onto a screen.
14. Concave/Convex mirror
15. Concave/Convex lens
16. Principle focus of concave/convex mirror
Halfway between the mirror surface and the mirror's optic center is the focal point. Focal point is important because the reflected rays (or the extension of the reflected rays) that are parallel to the axis will meet at the focal point
17. Focal length
Half of the radius of the sphere of the mirror is the focal length. Focal length is important because mirror equation is based on focal length
18. Principle axis
Principle axis is the line through the center of the mirror and the center of the sphere. Principle axis isn't scientifically important, but it can simplify the drawing of an reflected image.
19. Aberrations
Aberration is caused by differences in refractive index for different wavelengths of light
20. Dispersion of light (also known as "Spectrum")

When white light (which is a combination of all the colors of the visible spectrum) hits a glass prism, the beam is split into its components colors, with Red at the top, then orange, yellow, green, blue and violet at the bottom as red has the highest wavelength while violet has the lowest. This experiment is used to prove that the lower the wavelength the higher the refractive index (i.e refracting more) and you need to visualize the result of the experiment.