RayOptics Lab-1

Physics for Entertainment and Arts Lab Name Logan Staley Ray Optics and Lenses Objective: We will study the basics of ray optics and find image using ray diagrams. Theory: Light travels in straight lines beginning at the source of the light and will continue unless interrupted. In sketches, we will draw light rays as lines with an arrow pointing in the direction that the light is moving. Refraction: The speed of light in a vacuum is about 3x10 8 m/s. As light travels from one medium into another, the speed of light changes depending on the medium. For example the speed of light in glass is about 2x10 8 m/s. Because the speed of light changes depending on the medium, the light will bend as it moves from one medium to the next, when the light is at an angle to the boundary between the two media. This bending is called refraction . For an example of refraction in an optical system, think of a pencil sitting in a glass of water. When you look at the pencil from outside the glass, it appears the pencil is bent or broken due to the refraction of the light. Rainbows are also a product of refraction. The ratio of the speed of light in a vacuum to the speed of light in the medium is called the index of refraction, n. It determines how much the light bends as it moves from one medium to another. Converging lenses are curved pieces of glass, usually convex (outward curvature) on both sides that have focal points on either side of the lens. When parallel light rays, such as those coming from a distant star, hit the lens, they get refracted in such a way as to move through the focal point on the opposite end of the lens. Procedure: Part I. Refraction Go to https://www.physicsclassroom.com/Physics-Interactives/Refraction-and-Lenses/ Refraction/Refraction-Interactive 1

Physics for Entertainment and Arts Lab You can drag and move the laser emitter to adjust the incident angle to be between 30 and 50 degrees. Note that all angles need to be measured from the NORMAL line, NOT the interface of the two media. Click ‘Hide partial reflection’. Click ‘Show Protractor’. You can drag the protractor to adjust its position. Click ‘Go’ to see the beam of laser. Click ‘clear’ before each run. Are the last two columns the same or close enough? Last two Columns were close enough. Top Substance n 1 Bottom Substance n 2 Inciden t Angle θ 1 Refracte d Angle θ 2 n 1 * sin θ 1 n 2 * sin θ 2 Air (n=1.0003) Water(n =1.33) 40 30 0.64471597 25 0.665 Air (n=1.0003) Oil (n =1.47) 40 25 0.64471597 25 0.62124884 48 Water(n=1. 33) Oil (n =1.47) 40 35 0.85490752 09 0.84315736 14 Water(n=1. 33) Air (n=1.0003) 40 55 0.85490752 09 0.81939778 99 Part II: Lenses Ray Diagram Let’s develop our understanding of ray optics. We will use 3 types of rays to locate images when drawing diagrams. Note that all rays are coming from the tip of the object to the left of the lens. The image is formed by the light rays passing through the lens. Here are 3 special light rays. 1. Rays parallel to central axis (a line that passes through the center of the lens and is perpendicular to the lens) will refract through the focal point. 2

Physics for Entertainment and Arts Lab 20 44.1 -21.9 inverted Real 10 36.5 36.5 upright Virtual Is the image formed by a single convex(converging) lens always bigger or smaller? Or depends? Bigger . Is it always bigger or smaller than the object? Or depends. Depends . Is it always real or virtual? Or depends? depends Switch to diverging lens and repeat. d o (object distance) d i (image distance) h i (image size) Orientation (upright or inverted) Real or Virtual 60 10.9 1.9 upright Virtual 40 10 2.5 upright Virtual 20 8.1 4.1 upright Virtual 10 36.5 36.5 upright Virtual Is the image formed by a single convex(converging) lens always bigger or smaller? Or depends? smaller . Is it always bigger or smaller? Or depends? Smaller Is it always real or virtual? Or depends? virtual Note: This homework is almost identical to lab 9. If you are also taking the lab, you are advised to complete both. 4