We think you have liked this presentation. If you wish to download it, please recommend it to your friends in any social system. Share buttons are a little bit lower. Thank you!
Presentation is loading. Please wait.
Published byJudah Bucher
Modified over 2 years ago
© Boardworks Ltd 2003 Lenses
© Boardworks Ltd (c) Thin converging lens Core Describe the action of a thin converging lens on a beam of light Use the term principal focus and focal length Draw ray diagrams to illustrate the formation of a real image by a single lens
© Boardworks Ltd 2003 Supplement Draw ray diagrams to illustrate the formation of a virtual image by a single lens Use and describe the use of a single lens as a magnifying glass
© Boardworks Ltd 2003 Using refraction : lenses summary There are two main types of lens: Convex Concave Convex lenses work by bending [refracting] rays of light to a principal focus. The distance from the centre of the lens to the principal focus [F] is called the focal length [ƒ]. The image formed by a convex lens is inverted [back-to-front and upside-down]. The thicker the lens, the shorter the focal length[ƒ].
© Boardworks Ltd 2003 A lens can be thought of as a series of prisms. The lens refracts all the rays to a point called the principal focus [F]. The distance between the centre of the lens and F is called the focal length [ ]. Imagine parallel rays of light from a distant object hitting the lens. Draw normal lines [at 90° to the surface] for each ray. Use the first refraction rule to work out the ray direction. Draw normal lines where the rays enter the air [at 90º to the surface]. Work out the direction of the refracted rays using the second refraction rule. When light enters a less dense medium [e.g. air], it bends away from the normal. Using Refraction : lenses When light enters a more dense medium [e.g. glass], it bends towards the normal. F ƒ
© Boardworks Ltd 2003 What do you think happens when… Parallel light rays strike a convex lens? They pass through the focal point of the lens. Diverging light rays? Form a parallel beam if they pass though the focal point (F). F
© Boardworks Ltd 2003 Use a ruler to measure the distance between the lens and the screen - this is the focal length [ƒ]. Using Refraction : lenses - finding ƒ Chose a distant object [to get parallel rays of light]. Hold a plain white screen in one hand. Hold the lens in the other hand and move it closer to the screen until a clear image appears.
© Boardworks Ltd 2003 Refraction : lenses 1. Find the focal length [ƒ] of your lens. 2. Fix the lens to the centre of a metre rule and mark the distances F and 2F either side of the lens. 2FFF 3. Place the candle >2F away from the lens and move the screen until an image appears and record observations. 4. Repeat for the candle at 2F, between 2F and F, at F and between F and the lens.
© Boardworks Ltd 2003 Results Object position Image Position Real or virtual Magnified or diminished Inverted or erect >2F at 2F between 2F and F at F between F and lens
© Boardworks Ltd 2003 Refraction : lenses Object >2F away O 2FFF I The image [ l ] is formed between F and 2F away from the lens, is inverted and diminished.
© Boardworks Ltd 2003 Object at 2F O 2FFF I The image [ l ] is formed at 2F away from the lens, is inverted and the same size. Refraction : lenses
© Boardworks Ltd 2003 Object between 2Fand F away O 2FFF I The image [ l ] is formed further than 2F away from the lens, is inverted and magnified. Refraction : lenses
© Boardworks Ltd 2003 Object at F away O 2FFF The image [ l ] is formed at infinity - the rays never meet [we use this set-up for searchlights]. Refraction : lenses
© Boardworks Ltd 2003 Object between F and lens O I The VIRTUAL image [ l ] is formed on the same side of the lens as the object, is the right way up and magnified. 2FFF Refraction : A magnifying glass
© Boardworks Ltd 2003 Results Object position Image Position Real or virtual Magnified or diminished Inverted or erect >2F at 2F between 2F and F at F between F and lens between F and 2F at 2F > 2F at infinity same side as object virtual real magnified same size diminished erect inverted
© Boardworks Ltd FFF Magnification=Distance from lens to image Distance from object to lens Refraction : lenses
© Boardworks Ltd 2003 To do All P153 Answer all questions Extended only Draw an accurate ray diagram to show a magnifying glass where f=10cm and the object is 5cm from the lens
© Boardworks Ltd 2003 Learning check
© Boardworks Ltd 2003 Which of the following is the most dense? A.Air B.Water C.Glass D.Lead
© Boardworks Ltd 2003 When light changes direction as it moves from one medium to another we call this effect what? A.Reflection B.Refraction C.Diffraction D.Total internal reflection
© Boardworks Ltd 2003 What happens to the speed of light as it moves from air into glass? A.Decreases B.Increases C.No effect D.Decreases and increases
© Boardworks Ltd 2003 If a ray of light moves from air to glass parallel to the normal what happens? A.No change in direction B.It bends away from the normal C.It bends towards the normal D.It stops
© Boardworks Ltd 2003 If light travelling through a medium has a speed of m/s. What is the refractive index of the medium? A.2.6 B.0.5 C.2.0 D.1.5
© Boardworks Ltd 2003 Can you…… Draw ray diagrams depicting the refraction of light by lenses? Write a sentence using the terms principal focus and focal length Draw a ray diagrams to show how a lens forms an inverted image Draw ray diagrams to illustrate the formation of a virtual image by a magnifying glass
© Boardworks Ltd 2003
Light Lenses. Revision (refraction) Refraction occurs when the light ray changes mediums. Light traveling through air and then going through water is.
Light By Neil Bronks Light is a form of energy Crookes Radiometer proves light has energy Turns in sunlight as the light heats the black side.
Light, Reflection, & Mirrors AP Physics B. Facts about Light It is a form of Electromagnetic Energy It is a part of the Electromagnetic Spectrum and the.
© Boardworks Ltd 2003 Reflection 3.2 (a) Reflection of light Core Describe the formation, and give the characteristics, of an optical image by a plane.
Refraction and Lenses AP Physics B. Refraction Refraction is based on the idea that LIGHT is passing through one MEDIUM into another. The question is,
Chapter 36 - Lenses A PowerPoint Presentation by Paul E. Tippens, Professor of Physics Southern Polytechnic State University A PowerPoint Presentation.
Option G2: Optical Instruments. Thin Lenses A thin lens consists of a piece of glass or plastic, ground so that each of its two refracting surfaces is.
High School by SSL Technologies Physics Ex-55 Question-1 A translucent material: a) Absorbs the light rays it receives b) Converges the incident light.
Reflection w/ curved mirrors. Parabolic and circular mirrors All horizontal light rays reflect off the surface through a single focal point All horizontal.
1 Light & Waves L2 NCEA Achievement Standard 2.3 Text Book reference: Chapters 12,13 &14.
Optics Mirrors and Lenses Reflection We describe the path of light as straight-line raysWe describe the path of light as straight-line rays Reflection.
AP Physics B Lecture Notes Chapter 23 Mirrors and Lenses.
A concave mirror with a focal length of 10 cm creates a real image 30 cm away on its principal axis; the corresponding object is located how far from the.
Mirror and Lens by Rifki Irawan. a surface, such as polished metal or glass coated with a metal film, that reflects light without diffusion and produces.
© Boardworks Ltd of 20 © Boardworks Ltd of 47 KS3 Physics 8K Light.
Grade 8 Science Unit 2: Optics Chapter 6: Lenses refract light to form images.
Chapter 23. A long, thin light bulb illuminates a vertical aperture. Which pattern of light do you see on a viewing screen behind the aperture? (1) (2)
Learning Outcome Draw a ray diagram to find the position, nature and size of the image produced by a concave and convex mirrors.
J. Pulickeel SPH3U1 January Wave Behavior What type of waves do not travel through a medium? What types of waves travel through a medium? Name.
Chapter 2 Companion site for Light and Video Microscopy Author: Wayne.
Chapter 3 The Lens. Pinhole lens Light, hitting a solid barrier with a very small hole, admits straight rays of light that make an image when it hits.
TOC 1 Physics 212 and 222 Lenses Properties of Thin Lenses Lens Makers Equation Ray Tracing Equations.
Reflection and Refraction 1.REFLECTION Most objects we see reflect light.
Chapter 17 Geometrical Optics. Units of Chapter 17 The Reflection of Light Ray diagram for plane mirror Spherical Mirrors Ray Tracing and the Mirror Equation.
Refraction Refraction of Water Waves Light Rays in Glass Atmospheric Refraction Apparent Depth Refraction is responsible for why objects look bent in water.
April 2011 General Science. Bending Light Thursday April 12 th, 2012 Warm-up: 1. What is the angle of reflection equal to? Objective: Students will be.
High School Part 2 /2 by SSL Technologies Physics Ex-53 Click THE EYE The eye is an optical “instrument”. It contains a converging lens used to focus.
Laws of Reflection From the Activity you performed, when you shine an incident light ray at a plane mirror, the light is reflected off the mirror and.
Light. These are all LUMINOUS.LUMINOUS What are some sources of light?
Refraction. The bending of light when it travels from one medium to another Ex.
© 2016 SlidePlayer.com Inc. All rights reserved.