Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Introduction to Drawing Ray Diagrams Types of Mirrors and Lenses Plane Mirror – a mirror with a flat, reflective surface Convex Mirror – a mirror whose reflecting surface curves outward Concave Mirror – a mirror whose reflecting surface curves inward Lens – a transparent device with at least 1 curved surface that changes the direction of light passing through it (refracts light) *Rays are refracted at the surfaces of lenses according to Snell’s Law* Converging Lens – a lens that causes parallel light rays to come together, so that they cross at a single focal point (convex lenses) Diverging Lens – a lens that causes parallel light rays to spread apart, so that they appear to emerge from the virtual focal point (concave lenses) Terms for Ray Diagrams Optical Centre (O) / Vertex (V) – the geometric centre of all lenses Optical Axis (OA) – an imaginary vertical line through the optical centre Principle Axis (PA) – a horizontal line drawn through the optical centre Focal Point (F) – the point on the principal axis through which a group of rays parallel to the principal axis are refracted *F = ½ C Focal length (f) – the distance between the focal point and the optical centre, measured along the principle axis Centre / Radius of Curvature (C) – the centre of a sphere whose surface has been used to make the mirror or lens OA O or V PA C F F f C Drawing Mirrors and Lenses 1. Plane Mirror 4. Convex Lens 2. Convex Mirror 3. Concave Mirror 5. Concave Lens 4 Image Characteristics – SALT S – Size or Magnification Is the image smaller, larger, or the same size in comparison to the object? A – Attitude Which way is the image oriented compared to the object: upright or inverted? L – Location Where is the image relative to the mirror or lens? Is the image behind or in front of the mirror or lens? Where is the image in relation to C and F? T – Type Is the image real or virtual? *Real images can be projected onto a screen. *Virtual images cannot be projected onto a screen. Ray Diagrams 1. Images in a Plane Mirror Ray diagrams as per our SONG F and C do not exist, as there is no radius of curvature Memorize SALT for a plane mirror S – image is the same size as the object A – image is upright L – image is the same distance behind the mirror, as the object is in front of the mirror T – image is virtual (image is behind mirror – rays converge behind mirror) 2. Images in a Convex Mirror F and C are on the right side of the mirror Always draw rays starting from the top of the object Solid lines are used on the left; dotted lines are used on the right Steps for Locating Image Draw a ray // to PA, stopping at the mirror. From the edge of the mirror, angle ruler through F on the right side of the mirror. Extend this ray backwards on the left. Draw a ray through C. Place a dot where the first 2 rays intersect. Draw a ray to O, until the mirror is reached. Angle the ruler downwards towards the left, so that the ruler intersects the point. Draw this ray. S – smaller A – upright L – behind mirror (between O and F) T – virtual ( rays converge behind mirror) See example on DOV Camera. 3. Images in a Concave Mirror 1 2 3 4 5 Steps for Locating Image For (1-3): Draw ray #1 // to PA, stopping at the mirror. Angle ruler, so the same ray is refracted through F. Draw ray #2 through F, touching mirror below PA. Continue this ray // to PA. Place a dot at the intersection. Draw ray #3 to O, and angle ruler so that this ray reaches the point of intersection. All rays will be on left side of mirror with solid lines. For 4: Draw ray #1. Ray #2 cannot be drawn. Draw ray #3 to O, and then continue this ray // to ray #1. For 5: Draw ray #1. Extend the ray intersecting F backwards on the right side of the mirror using a dotted line. Ray #2 cannot be drawn. Draw ray #3 to O, and angle ruler so that ray #1 and ray #3 are skew rays. Extend ray #3 backwards with a dotted line. Draw image. S A L T 1 Smaller than object 2 Same size Inverted At C 3 Larger than object Between F Beyond C &C Real (rays converge in front of mirror) See 5 DOV Camera examples. 4 No image (reflected rays are // and never converge) 5 Larger than object Upright Behind mirror Virtual (rays converge behind mirror) 4. Images in a Convex Lens 1 2 3 C 4 5 F F C Steps for Locating Image For (1-3): Draw ray #1 // to PA, stopping at lens. Extend this ray through F on the right side. Draw ray #2 through O, intersecting through ray #1. Place a dot where the 2 rays intersect. Draw ray #3 through F on the left side, stopping at lens. Continue ray // to PA, through the intersection point. For 4: Draw ray #1. Draw ray #2 through O, realizing rays will never converge (// rays). Ray #3 cannot be drawn. For 5: Draw ray #1. Extend the ray intersecting F backwards on the left side of the lens using a dotted line. Draw ray #2 through O, ensuring ray #1 and ray #2 are skew rays. Extend ray #2 backwards with a dotted line. Draw image. S A L T 1 Smaller than object Between F &C 2 Same size Inverted At C 3 Larger than object Beyond C Real (rays converge after going through lens) See 5 DOV Camera examples. 4 No image (refracted rays are // and never converge) 5 Larger than object Upright Same side as object (left of object) Virtual (rays must be extended back to converge) 5. Images in a Concave Lens Steps for Locating Image Draw ray #1 // to PA, stopping at lens. Angle ruler so that ray passes through F on the left side with a dotted line. Extend this ray backwards on the right side with a solid line. Draw ray #2 through F on the right side. This ray will be solid on the left, and dotted on the right. Angle ruler to create ray #3 // to PA, ensuring there is a POI with the lens. Ray must be dotted on left and solid on the right. Draw ray #4 through O with a solid line. Ray #1, 3, and 4 will intersect. S – smaller than object A – upright L – same side as object (between F and lens) T – virtual (rays must be extended back to converge) See DOV Camera example.