# The Law Of Reflection And Snell 's Law

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We see optics in all types of instruments. Microscopes magnify extremely tiny objects so that they are visible. Telescopes concentrate light from very distant objects to allow us to see extremely far away. Glasses allow people with poor vison to see clearly. Some instruments use both lenses and mirrors making them very powerful, but also complicated.

Optics is the study of how light interacts with other objects. In geometric optics light is assumed to travel in a straight line except where it meets barriers. Depending on the material of the barrier the light is either reflected (mirrors) or refracted (lenses). The angle at which this occurs is determined by two laws, the law of reflection and Snell’s law.

A mirror is typically a
III. Methods / Procedure

A. Materials

-Yard stick -Light source -Laser pointer
-Refraction cell -Convex lens -Clear liquid
-Mirror holder -Protractor -Candle

B. Diagram of Lab Setup

C. Steps Taken

Index of refraction
1. Print out a 360-degree protractor.
2. Fill refraction cell with clear liquid.
3. Place refraction cell so that flat edge is in-line with 0 and 270-degrees.
4. Use laser pointer as light source.
5. Hold laser pointer perpendicular to flat surface of refraction cell and mark angle coming out of the other side.
6. Move laser pointer 10-degrees from normal and mark angle on other side.
7. Repeat for angles of 20, 30, 40, 50, 60, 70, 80-degrees.
8. Record all data into a table.

Focal length of convex lens
1. Set up a screen across from window.
2. Place convex lens into mirror holder.
3. Place mirror holder at base of screen and slowly move away from the screen.
4. When image comes into focus, move slowly until image appears to be crisp.
5. Measure distance from screen to lens.
6. This is experimental focal point, record in data table.

Testing focal length
1. Setup yard stick with screen at one end and candle at other end of yard stick.
2. Move mirror stand with convex lens until candle flame