Exemplar for Internal Achievement Standard Level 2

Size: px
Start display at page:

Download "Exemplar for Internal Achievement Standard Level 2"

Transcription

1 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Exemplar for Internal Achievement Standard Level 2 This exemplar supports assessment against: Achievement Standard Demonstrate understanding of physics relevant to a selected context An annotated exemplar is an extract of student evidence, with a commentary, to explain key aspects of the standard. It assists teachers to make assessment judgements at the grade boundaries. New Zealand Qualifications Authority To support internal assessment NZQA 2014

2 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: Low Excellence 1. For Excellence, the student needs to demonstrate comprehensive understanding of physics relevant to a selected context. This involves linking ideas to integrate physics relevant to the selected context. It may involve elaborating, justifying, relating, evaluating, comparing and contrasting, or analysing the physics underpinning the context. The student has demonstrated comprehensive understanding of how principles of physics are relevant to the correction of impaired vision. The student has linked the focal length of a convex lens to its shape (1), and has justified the use of a concave lens to correct short sightedness (2). The student had made an attempt to elaborate on the use of a concave lens to correct short sightedness by attempting to link the focal length of the lens with the severity of the deficiency (3). The use of silicone instead of water has been justified in terms of the wear-ability of the glasses, and the safety of the substance for the wearer (4). For a more secure Excellence, the student could: explain long sightedness and how it can be corrected give a more comprehensive explanation for how a concave lens can correct short sightedness. NZQA 2014

3 Student 1: Low Excellence When we look at something the light rays from the object first enter our cornea, which is the transparent dome on the outside of the eye. The iris, the colour muscle of the eye which controls the size of the pupil, controls the amount of light according to light conditions so it controls the amount of light that enters the pupil after it travels through the cornea. After light rays reach the pupil, they reach the lens whose shape is controlled by ciliary muscles and the lens focuses the light rays on the retina. Once light rays reach the retina, the light sensitive receptors; cones and rods, in the retina change the light rays into electrical impulses which are then sent down through the optic nerve to the brain, which then tells us what we are looking at. (Image of the eye given not included here) Since most of our vision is not 100% effective we don t all have 20/20 vision. Different types of lenses can be used to correct inaccuracy. There are two types of lens, concave and convex. A concave lens diverges light rays to a virtual point and is fatter on the edges than it is in the centre whereas convex lenses converge light rays to a point and are fatter in the middle than they are at the edges. Lenses can either produce a real image or a virtual image. Having knowledge of both concave and convex lenses, helps us to solve eye problems such as short and long sightedness. Short sightedness, is when people find it hard to see objects far away because the light rays are focused in front of the retina. To make the rays focus further back (on the retina) the focal length of the lens has to be made longer by making the lens thinner but the ciliary muscles aren t strong enough to do this. Short sighted people can see things clearly close up because the light enters the eye at a slightly diverging angle which means the rays have to be bent more to get them on to the retina. Fatter lenses have a shorter focal length so can bend light more and so the ciliary muscles just relax till the lens is fat enough. [1]. Short sightedness can be corrected by concave lenses which make the light rays diverge before they enter the lens, just like they are when they are when they are coming from close things, so the light rays can be bent enough to meet at the retina. John Silver used this knowledge of how concave lenses are used to correct short sightedness to create his fluid filled lenses. The silicone oil used in the flexible membrane controls the shape of the lens. As fluid is pumped out, the centre of the lens membranes will pinch in together to create a concave lens suitable for short sighted people. The more short sighted a person is the more fluid they pump out the lens to create a thinner concave lens which has a shorter focal length and so can bend the light more. [3] [2]

4 In order to understand or justify the materials John Silver used to create his fluid filled lenses it is essential to understand the terms refraction and refractive index. Refraction is when light is bent when it travels through two mediums with different optical densities. The index of refraction is the ratio of the speed light rays travel in a vacuum compared to the speed they travel in the new substance. For example water has a refractive index of 1.33 so light travels 1.33 times faster in a vacuum than it does in water. Therefore this justifies why John Silver used silicone oil as a material for filling up the lenses because silicone oil has a refractive index of which is higher than the refractive index of water 1.33 so silicone oil refracts light more than water, for the same amount of liquid. Therefore a thin silicone oil lens, with a higher refractive index will have the same effect as a thicker water filled lens with a lower refractive index. It is more desirable to use a thinner lens than a thicker lens because it is less bulky and lighter therefore silicone oil is a better option than water. [4] John Silver having known the basic principles of refraction, refractive index, concave lens, convex lens, short sightedness, he created fluid filled lenses using the appropriate materials. He was a very clever man and his invention could change the world for the better.

5 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: High Merit 2. For Merit, the student needs to demonstrate in-depth understanding of physics relevant to a selected context. This involves providing reasons as to how or why the physics applies to the selected context. This student has demonstrated in-depth understanding of how principles of physics are relevant to the correction of impaired vision. The student has used diagrams to show how the thickness of a lens affects the amount of bending and has attempted to link this to the focal length of the lens (1). The student has also used diagrams to show how long sightedness (2) and short sightedness (3) can be corrected. Reasons are given for why silicon oil is used in the adjustable glasses (4). To reach Excellence, the student could demonstrate comprehensive understanding by: showing, on the diagram, how the focal length of each type of lens can be determined, and then explain the relevance of focal length with respect to the shape of the eyeball explaining why the bending of the light by the corrective lens enables the eye lens to focus on the retina, and why different degrees of sight defect require lenses of different power explaining the need for the adjustable lenses to be able to change the shape of the lens (relating the explanation to differing degrees of sight), and hence explaining the relevance of why a higher refractive index fluid is desirable. NZQA 2014

6 Student 2: High Merit Lenses are transparent objects made normally from glass or plastic. As light travels through the lens, it bends or refracts. Different mediums refract light differently depending on their optical density. This is measured using a refractive index. The higher the RI the more the light bends as it passes into the medium. For lenses, another factor that changes how much light bends, is the focal length of the lens. Focal length depends on how thick the lens is. For example the thicker a lens is, the more the light will bend and so the shorter the focal length. [1] We use lenses all the time in everyday life, in microscopes, telescopes, cameras but most importantly in glasses. Eye glasses are used to correct problems that we can get with our eyes. Long sightedness is when the eye cannot focus on objects close up, so the person can only see long distances. This can be caused by the eye ball being too small, so the image that the eye sees does not fall upon the back of the eye (on the retina) but behind it. Long sightedness can be corrected by a convex lens, as the convex lens causes the light rays to converge further forward on the retina. Normal sight Long sight Corrected sight [2] Short sightedness is when the eye cannot focus on objects far away so the person can only see short distances. This can be caused by the front of the eye being more curved than round or the eye ball being too long, so the image falls before the retina, rather than on it. Short sightedness can be corrected by a concave lens, as the concave lens causes the light rays to diverge further before the lens in the eye converges the light rays on the back of the eye. Normal sight Short sight Corrected sight [3] New fluid filled adjustable lenses are now available they are much like normal glasses only the glass lens is replaced with flexible plastic lens with a compartment of silicon oil, and there is an adjustable pump on the side of the glasses. The pump can pump the silicon oil in and out of the compartment changing the shape of the lens to suit each person s individual eye needs. Silicon oil is used instead of water, as silicone oil has a refractive index (light bending value) of This is higher than the light

7 bending value of some other liquid, such as water (RI of 1.33) Therefore, less silicone oil would be necessary to bend light compared to a larger amount of water. [4]

8 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: Low Merit 3. For Merit, the student needs to demonstrate in-depth understanding of physics relevant to a selected context. This involves providing reasons as to how or why the physics applies to the selected context. This student has demonstrated in-depth understanding of how principles of physics are relevant to the correction of impaired vision. The student has given reasons why a concave lens can correct short sightedness (1). The student has also attempted to give reasons why a convex lens can correct long sightedness (2). The student has attempted to give reasons why silicone oil is used in the fluid filled adjustable glasses (3). For a more secure Merit, the student could demonstrate further depth by: showing understanding of the nature of long sightedness by showing the incident rays diverging from a close object, rather than arriving parallel from a far object giving a more comprehensive reason why silicone oil is used in the lenses of the adjustable glasses. NZQA 2014

9 Student 3: Low Merit There are two types of lenses convex and concave. Convex lenses are lenses that curve outwards, they converge parallel light rays to a focal point. Concave lenses are thinner in the middle and thicker at their edges. Concave lenses diverge parallel light rays away from each other. Lenses are able to correct short sightedness because short sightedness is when the light that comes to the convex lens in your eyes converges (meets) at a focal point before your retina. (You can only see an image when the light ray s focal point falls on the retina). So when you wear glasses they put a concave lens in them which diverges the light rays before they meet the lens in your eye so that when they do converge after going through your lens they converge to a point on your retina and the image is no longer blurry and you can see. [1] Long sightedness is when the lens converges the light rays but they don t meet on your retina. Instead, if they could. they would come to a point after the retina. And so they use a convex lens to converge the light rays before they reach your eye so then when your eye s lens converges them again the focal point is reached on the retina. It is necessary to pump fluid in and out of the lens to change their shape between concave and convex to become the type of lens that the person needs to be able to see. So for example if they were short sighted the liquid would be pumped out to create a concave lens to help them see. Silicone was used instead of other substances like water because it is more dense and so it has a higher refractive index. Water has a refractive index of 1.33 whereas silicone is This means that the lens doesn t have to be so thick to converge/diverge the light rays to the right extent needed for the person to see [3]. If they used water to fill the lenses they would become thicker and the glasses and flexible membrane would have to be bigger to cater for the larger lens. [2]

10 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: High Achieved 4. For Achieved, the student needs to demonstrate understanding of physics relevant to a selected context. This involves providing characteristics of, or an account of the physics related to the selected context. The student has demonstrated understanding of how principles of physics are relevant to the correction of impaired vision. The student has described how convex and concave lenses bend parallel light (2). The student has described long and short-sightedness, and has attempted to give reasons for why they happen (3) (4) A description is provided for how both long and short sight can be corrected (5). To reach Merit, the student could demonstrate in-depth understanding by: giving clearer reasons for why refraction occurs stating what is meant by the term power, and given reasons why it is relevant in the situations of long-sightedness and short-sightedness explaining correctly why the image is produced in front of the retina for short-sightedness. NZQA 2014

11 Student 4: High Achieved Refraction is the bending of light, it occurs as the speed of light changes as it moves from one medium to another. The denser a substance is, the more difficult it is for the light to travel [1]. Lenses are transparent material; there are two types of lenses, concave and convex. concave convex Refraction occurs when light travels through these lenses. In a concave lens the parallel light rays are diverged and in a convex lens the light rays are converged [2]. If someone is long sighted it means that close objects are blurry or fuzzy and distant objects are not blurred. This is because light rays don t need as much power to focus, so they can focus on your retina properly. If you are long sighted the light rays focus behind your retina, this can be because your eyeball is too short [3]. If you are short sighted it means that you can see close objects well, but distant objects appear to be blurry and fuzzy. As parallel light rays enter your eye, the lens causes them to focus behind the retina, so the image is produced in front of the retina. This can be due to your eyeball being too long from the front [4]. To correct short sight a concave lens is used. The concave lens will cause the parallel light rays to diverge then converge, this causes the image to be produced on the retina, so a clear image can be seen. To correct long sight from the image being produced past the retina to on the retina, a convex lens is used. A convex lens makes the light rays converge, then converge again to form an image on the retina, after this the person can see a clear image, as it is formed on the retina. The fluid filled lens is necessary to have fluid pumped in and out of it as you have to make it adjustable to your eye sight. Silicon oil has a refractive index of Silicon oil is used instead of water because water has a refractive index of Silicon oil is more suitable to use as it has a slight higher refractive index, so less oil has to be used, to correct the vision. [5]

12 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: Low Achieved 5. For Achieved, the student needs to demonstrate understanding of physics relevant to a selected context. This involves providing characteristics of, or an account of the physics related to the selected context. This student has demonstrated some understanding of how principles of physics are relevant to the correction of impaired vision. The student has described the process of refraction (1), attempted to describe the physics of how lenses correct eye defects (2), and attempted to account for the choice of silicon oil for the fluid in the adjustable lenses (3). For a more secure Achieved, the student could: include appropriate ray diagrams to describe the physics of how lenses correct eye defects describe the significance of refractive index in the choice of adjustable lens fluid. NZQA 2014

13 Student 5: Low Achieved A lens is a transparent material with a curved surface. Refraction is the bending of light as it changes from one medium to another. [1] There are two main types of lenses, converging lens (convex) or a diverging lens (concave). A converging lens has an outward curving surface, with the lens being thicker at the centre as opposed to the edges. A diverging lens has inward facing curving surfaces, with the lens being thicker at the edges as opposed to the centre. Short-sightedness is when a person has difficulty focusing on objects far away due to the light rays being focused in front of the retina. They can only see close objects clearly. In order to correct this vision, a concave lens would be used so that the light is bent outwards before it enters the eye. Long-sightedness is when a person can see things far away clearly, but their eye lens is too weak to focus on close objects, this is because the light rays are focused behind the retina (converge). This sight problem can be corrected by using convex lenses so that the light is bent inwards before it enters the eye. [2] It is necessary to be able to pump the fluid in and out of the adjustable lenses because it is necessary to make sure the person s vision is clear. This way you do not have to change the physical shape of the lens as that is what the liquid does. It changes the glasses to create either a convex or concave lens to aid the person depending on whether they are long or short sighted. The choice of silicone oil in this design is good as they used it because it has a higher refractive index then water, but lower than glass and plastic. Because of this higher refractive index it would not be as thick as putting in water. This makes the glasses more suitable, not a chunky shape which looks funny on. It can refract more light for the same amount of fluid with its refractive index of as opposed to water s [3]

14 Exemplar for internal assessment resource Physics 2.2A for Achievement Standard Grade Boundary: High Not Achieved 6. For Achieved, the student needs to demonstrate understanding of physics relevant to a selected context. This involves providing characteristics of, or an account of the physics related to the selected context. This student has discussed the relevance of principles of physics that are relevant to the correction of impaired vision. The student has attempted to describe the physics of how different shaped lenses refract light to different degrees (1) (4). The student has attempted to describe the physics of how lenses can correct sight defects (2) (3). To reach Achieved, the student could: include appropriate diagrams to describe more clearly how lenses can be used to correct eye defects define relevant terms such as refractive power give more detailed descriptions. NZQA 2014

15 Student 6: High Not Achieved Our eyes have our own flexible lens. This enables us to change our focus to near or far objects. The lens is surrounded by a ring muscle called the ciliary muscle. This relaxes to allow the lens to contract changing its refractive power. Light is refracted to focus as it passes through the lens [1]. Short sightedness results in blurred distance vision. You will have difficulty looking at distance objects but close objects won t be a problem. People with short-sightedness can see well because when they look into near objects the light gets bent slightly outward. Concave prescription lens are used when you are short sighted because these are used to bend light rays slightly outward. The light ray will be at a greater angle to bend back to focus when it travels through the eye lens [2]. If you are long sighted you will have difficulty seeing objects that are close up. This happens when the length from the front to the back of the eye is too short. Some people have this because the cornea lens does not have enough curvature. Convex lenses are used to treat long sightedness, because they bend light so the retina can focus [3], and these kinds of lenses are thinner at the edge than at the centre. Adjustable lenses can change the refractive power. The power of the lens is changed whether you pump in or pump out fluid because it changes the curvature [4]. When fluid is pumped out it reduces the power of the lens and this is suitable for short sightedness and when fluid is pumped in, this increases the power of the lens and this is good for longsightedness.

Topic 4: Lenses and Vision. Lens a curved transparent material through which light passes (transmit) Ex) glass, plastic

Topic 4: Lenses and Vision. Lens a curved transparent material through which light passes (transmit) Ex) glass, plastic Topic 4: Lenses and Vision Lens a curved transparent material through which light passes (transmit) Ex) glass, plastic Double Concave Lenses Are thinner and flatter in the middle than around the edges.

More information

The Human Eye and a Camera 12.1

The Human Eye and a Camera 12.1 The Human Eye and a Camera 12.1 The human eye is an amazing optical device that allows us to see objects near and far, in bright light and dim light. Although the details of how we see are complex, the

More information

Chapter 24 Geometrical Optics. Copyright 2010 Pearson Education, Inc.

Chapter 24 Geometrical Optics. Copyright 2010 Pearson Education, Inc. Chapter 24 Geometrical Optics Lenses convex (converging) concave (diverging) Mirrors Ray Tracing for Mirrors We use three principal rays in finding the image produced by a curved mirror. The parallel ray

More information

Class 10 Science NCERT Exemplar Solutions Human Eye and Colourful World

Class 10 Science NCERT Exemplar Solutions Human Eye and Colourful World Class 10 Science NCERT Exemplar Solutions Human Eye and Colourful World Short Answer Questions Question 1. A student sitting at the back of the classroom cannot read clearly the letters written on the

More information

Science 8 Unit 2 Pack:

Science 8 Unit 2 Pack: Science 8 Unit 2 Pack: Name Page 0 Section 4.1 : The Properties of Waves Pages By the end of section 4.1 you should be able to understand the following: Waves are disturbances that transmit energy from

More information

PHYS:1200 LECTURE 31 LIGHT AND OPTICS (3)

PHYS:1200 LECTURE 31 LIGHT AND OPTICS (3) 1 PHYS:1200 LECTURE 31 LIGHT AND OPTICS (3) In lecture 30, we applied the law of reflection to understand how images are formed using plane and curved mirrors. In this lecture we will use the law of refraction

More information

Lenses. A lens is any glass, plastic or transparent refractive medium with two opposite faces, and at least one of the faces must be curved.

Lenses. A lens is any glass, plastic or transparent refractive medium with two opposite faces, and at least one of the faces must be curved. PHYSICS NOTES ON A lens is any glass, plastic or transparent refractive medium with two opposite faces, and at least one of the faces must be curved. Types of There are two types of basic lenses. (1.)

More information

Life Science Chapter 2 Study Guide

Life Science Chapter 2 Study Guide Key concepts and definitions Waves and the Electromagnetic Spectrum Wave Energy Medium Mechanical waves Amplitude Wavelength Frequency Speed Properties of Waves (pages 40-41) Trough Crest Hertz Electromagnetic

More information

Unit 3: Chapter 6. Refraction

Unit 3: Chapter 6. Refraction Unit 3: Chapter 6 Refraction Refraction of Visible Light 2 Examples: 1. Bent-stick effect: When light passes from one medium to another (ex: from air into water), the change of speed causes it to change

More information

sclera pupil What happens to light that enters the eye?

sclera pupil What happens to light that enters the eye? Human Vision Textbook pages 202 215 Before You Read Some people can see things clearly from a great distance. Other people can see things clearly only when they are nearby. Why might this be? Write your

More information

Lenses. Images. Difference between Real and Virtual Images

Lenses. Images. Difference between Real and Virtual Images Linear Magnification (m) This is the factor by which the size of the object has been magnified by the lens in a direction which is perpendicular to the axis of the lens. Linear magnification can be calculated

More information

Introduction. Strand F Unit 3: Optics. Learning Objectives. Introduction. At the end of this unit you should be able to;

Introduction. Strand F Unit 3: Optics. Learning Objectives. Introduction. At the end of this unit you should be able to; Learning Objectives At the end of this unit you should be able to; Identify converging and diverging lenses from their curvature Construct ray diagrams for converging and diverging lenses in order to locate

More information

L. R. & S. M. VISSANJI ACADEMY SECONDARY SECTION PHYSICS-GRADE: VIII OPTICAL INSTRUMENTS

L. R. & S. M. VISSANJI ACADEMY SECONDARY SECTION PHYSICS-GRADE: VIII OPTICAL INSTRUMENTS L. R. & S. M. VISSANJI ACADEMY SECONDARY SECTION - 2016-17 PHYSICS-GRADE: VIII OPTICAL INSTRUMENTS SIMPLE MICROSCOPE A simple microscope consists of a single convex lens of a short focal length. The object

More information

Optics Review (Chapters 11, 12, 13)

Optics Review (Chapters 11, 12, 13) Optics Review (Chapters 11, 12, 13) Complete the following questions in preparation for your test on FRIDAY. The notes that you need are in italics. Try to answer it on your own first, then check with

More information

Chapter 6 Human Vision

Chapter 6 Human Vision Chapter 6 Notes: Human Vision Name: Block: Human Vision The Humane Eye: 8) 1) 2) 9) 10) 4) 5) 11) 12) 3) 13) 6) 7) Functions of the Eye: 1) Cornea a transparent tissue the iris and pupil; provides most

More information

Unit 2: Optics Part 2

Unit 2: Optics Part 2 Unit 2: Optics Part 2 Refraction of Visible Light 1. Bent-stick effect: When light passes from one medium to another (for example, when a beam of light passes through air and into water, or vice versa),

More information

30 Lenses. Lenses change the paths of light.

30 Lenses. Lenses change the paths of light. Lenses change the paths of light. A light ray bends as it enters glass and bends again as it leaves. Light passing through glass of a certain shape can form an image that appears larger, smaller, closer,

More information

Chapter Human Vision

Chapter Human Vision Chapter 6 6.1 Human Vision How Light Enters the Eye Light enters the eye through the pupil. The pupil appears dark because light passes through it without reflecting back Pupil Iris = Coloured circle of

More information

Refraction, Lenses, and Prisms

Refraction, Lenses, and Prisms CHAPTER 16 14 SECTION Sound and Light Refraction, Lenses, and Prisms KEY IDEAS As you read this section, keep these questions in mind: What happens to light when it passes from one medium to another? How

More information

Physics 11. Unit 8 Geometric Optics Part 2

Physics 11. Unit 8 Geometric Optics Part 2 Physics 11 Unit 8 Geometric Optics Part 2 (c) Refraction (i) Introduction: Snell s law Like water waves, when light is traveling from one medium to another, not only does its wavelength, and in turn the

More information

Chapter 11 Human Eye and Colourful World Question 1: What is meant by power of accommodation of the eye? When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases, and

More information

Lenses- Worksheet. (Use a ray box to answer questions 3 to 7)

Lenses- Worksheet. (Use a ray box to answer questions 3 to 7) Lenses- Worksheet 1. Look at the lenses in front of you and try to distinguish the different types of lenses? Describe each type and record its characteristics. 2. Using the lenses in front of you, look

More information

Human Eye and Colourful World Science. Intext Exercise 1

Human Eye and Colourful World Science. Intext Exercise 1 Intext Exercise 1 Question 1: What is meant by power of accommodation of the eye? Solution 1: When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases, and the distant

More information

3. Study the diagram given below and answer the questions that follow it:

3. Study the diagram given below and answer the questions that follow it: CH- Human Eye and Colourful World 1. A 14-year old student is not able to see clearly the questions written on the blackboard placed at a distance of 5 m from him. (a) Name the defect of vision he is suffering

More information

SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to:

SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to: SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to: Eric Hamber Secondary 5025 Willow Street Vancouver, BC Table of Contents A. Chapter 6.1 Parts of the eye.. Parts of

More information

Sense Organs (Eye) The eye is the sense organ of sight. The eye is shaped like a ball and is located in bony

Sense Organs (Eye) The eye is the sense organ of sight. The eye is shaped like a ball and is located in bony Sense Organs (Eye) The eye is the sense organ of sight. The eye is shaped like a ball and is located in bony sockets in the skull. It is held in place by six muscles which are joined to the outside of

More information

Unit 3: Energy On the Move

Unit 3: Energy On the Move 14 14 Table of Contents Unit 3: Energy On the Move Chapter 14: Mirrors and Lenses 14.1: Mirrors 14.2: Lenses 14.3: Optical Instruments 14.1 Mirrors How do you use light to see? When light travels from

More information

Lecture Outline Chapter 27. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.

Lecture Outline Chapter 27. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc. Lecture Outline Chapter 27 Physics, 4 th Edition James S. Walker Chapter 27 Optical Instruments Units of Chapter 27 The Human Eye and the Camera Lenses in Combination and Corrective Optics The Magnifying

More information

Instructions. To run the slideshow:

Instructions. To run the slideshow: Instructions To run the slideshow: Click: view full screen mode, or press Ctrl +L. Left click advances one slide, right click returns to previous slide. To exit the slideshow press the Esc key. Optical

More information

SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to:

SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to: SCIENCE 8 WORKBOOK Chapter 6 Human Vision Ms. Jamieson 2018 This workbook belongs to: Eric Hamber Secondary 5025 Willow Street Vancouver, BC Table of Contents A. Chapter 6.1 Parts of the eye.. Parts of

More information

CHAPTER 11 The Hyman Eye and the Colourful World In this chapter we will study Human eye that uses the light and enable us to see the objects. We will also use the idea of refraction of light in some optical

More information

EYE. The eye is an extension of the brain

EYE. The eye is an extension of the brain I SEE YOU EYE The eye is an extension of the brain Eye brain proxomity Can you see : the optic nerve bundle? Spinal cord? The human Eye The eye is the sense organ for light. Receptors for light are found

More information

The Hyman Eye and the Colourful World

The Hyman Eye and the Colourful World The Hyman Eye and the Colourful World In this chapter we will study Human eye that uses the light and enable us to see the objects. We will also use the idea of refraction of light in some optical phenomena

More information

c v n = n r Sin n c = n i Refraction of Light Index of Refraction Snell s Law or Refraction Example Problem Total Internal Reflection Optics

c v n = n r Sin n c = n i Refraction of Light Index of Refraction Snell s Law or Refraction Example Problem Total Internal Reflection Optics Refraction is the bending of the path of a light wave as it passes from one material into another material. Refraction occurs at the boundary and is caused by a change in the speed of the light wave upon

More information

General Physics - E&M (PHY 1308) - Lecture Notes. General Physics - E&M (PHY 1308) Lecture Notes

General Physics - E&M (PHY 1308) - Lecture Notes. General Physics - E&M (PHY 1308) Lecture Notes General Physics - E&M (PHY 1308) Lecture Notes Lecture 036: Application of Lenses - the Human Eye SteveSekula, 1 December 2010 (created 30 November 2010) Goals of this lecture no tags conclude the discussion

More information

Exam 3--PHYS 151--S15

Exam 3--PHYS 151--S15 Name: Class: Date: Exam 3--PHYS 151--S15 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Consider this diagram of the eye and answer the following questions.

More information

Grade 8. Light and Optics. Unit exam

Grade 8. Light and Optics. Unit exam Grade 8 Light and Optics Unit exam Unit C - Light and Optics 1. Over the years many scientists have contributed to our understanding of light. All the properties listed below about light are correct except:

More information

Mastery. Chapter Content. What is light? CHAPTER 11 LESSON 1 C A

Mastery. Chapter Content. What is light? CHAPTER 11 LESSON 1 C A Chapter Content Mastery What is light? LESSON 1 Directions: Use the letters on the diagram to identify the parts of the wave listed below. Write the correct letters on the line provided. 1. amplitude 2.

More information

used to diagnose and treat medical conditions. State the precautions necessary when X ray machines and CT scanners are used.

used to diagnose and treat medical conditions. State the precautions necessary when X ray machines and CT scanners are used. Page 1 State the properties of X rays. Describe how X rays can be used to diagnose and treat medical conditions. State the precautions necessary when X ray machines and CT scanners are used. What is meant

More information

SNC2D PHYSICS 5/25/2013. LIGHT & GEOMETRIC OPTICS L Converging & Diverging Lenses (P ) Curved Lenses. Curved Lenses

SNC2D PHYSICS 5/25/2013. LIGHT & GEOMETRIC OPTICS L Converging & Diverging Lenses (P ) Curved Lenses. Curved Lenses SNC2D PHYSICS LIGHT & GEOMETRIC OPTICS L Converging & Diverging Lenses (P.448-450) Curved Lenses We see the world through lenses even if we do not wear glasses or contacts. We all have natural lenses in

More information

Physics Chapter Review Chapter 25- The Eye and Optical Instruments Ethan Blitstein

Physics Chapter Review Chapter 25- The Eye and Optical Instruments Ethan Blitstein Physics Chapter Review Chapter 25- The Eye and Optical Instruments Ethan Blitstein The Human Eye As light enters through the human eye it first passes through the cornea (a thin transparent membrane of

More information

Where should the fisherman aim? The fish is not moving.

Where should the fisherman aim? The fish is not moving. Where should the fisherman aim? The fish is not moving. When a wave hits a boundary it can Reflect Refract Reflect and Refract Be Absorbed Refraction The change in speed and direction of a wave Due to

More information

Chapter 29/30. Wave Fronts and Rays. Refraction of Sound. Dispersion in a Prism. Index of Refraction. Refraction and Lenses

Chapter 29/30. Wave Fronts and Rays. Refraction of Sound. Dispersion in a Prism. Index of Refraction. Refraction and Lenses Chapter 29/30 Refraction and Lenses Refraction Refraction the bending of waves as they pass from one medium into another. Caused by a change in the average speed of light. Analogy A car that drives off

More information

REFLECTION THROUGH LENS

REFLECTION THROUGH LENS REFLECTION THROUGH LENS A lens is a piece of transparent optical material with one or two curved surfaces to refract light rays. It may converge or diverge light rays to form an image. Lenses are mostly

More information

Vision. The eye. Image formation. Eye defects & corrective lenses. Visual acuity. Colour vision. Lecture 3.5

Vision. The eye. Image formation. Eye defects & corrective lenses. Visual acuity. Colour vision. Lecture 3.5 Lecture 3.5 Vision The eye Image formation Eye defects & corrective lenses Visual acuity Colour vision Vision http://www.wired.com/wiredscience/2009/04/schizoillusion/ Perception of light--- eye-brain

More information

Instructional Resources/Materials: Light vocabulary cards printed (class set) Enough for each student (See card sort below)

Instructional Resources/Materials: Light vocabulary cards printed (class set) Enough for each student (See card sort below) Grade Level/Course: Grade 7 Life Science Lesson/Unit Plan Name: Light Card Sort Rationale/Lesson Abstract: Light vocabulary building, students identify and share vocabulary meaning. Timeframe: 10 to 20

More information

Light sources can be natural or artificial (man-made)

Light sources can be natural or artificial (man-made) Light The Sun is our major source of light Light sources can be natural or artificial (man-made) People and insects do not see the same type of light - people see visible light - insects see ultraviolet

More information

Chapter 23 Study Questions Name: Class:

Chapter 23 Study Questions Name: Class: Chapter 23 Study Questions Name: Class: Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. When you look at yourself in a plane mirror, you

More information

12.1. Human Perception of Light. Perceiving Light

12.1. Human Perception of Light. Perceiving Light 12.1 Human Perception of Light Here is a summary of what you will learn in this section: Focussing of light in your eye is accomplished by the cornea, the lens, and the fluids contained in your eye. Light

More information

L 32 Light and Optics [2] The rainbow. Why is it a rain BOW? Atmospheric scattering. Different colors are refracted (bent) by different amounts

L 32 Light and Optics [2] The rainbow. Why is it a rain BOW? Atmospheric scattering. Different colors are refracted (bent) by different amounts L 32 Light and Optics [2] Measurements of the speed of light The bending of light refraction Total internal reflection Dispersion Dispersion Rainbows Atmospheric scattering Blue sky and red sunsets Mirrors

More information

Lenses. A transparent object used to change the path of light Examples: Human eye Eye glasses Camera Microscope Telescope

Lenses. A transparent object used to change the path of light Examples: Human eye Eye glasses Camera Microscope Telescope SNC2D Lenses A transparent object used to change the path of light Examples: Human eye Eye glasses Camera Microscope Telescope Reading stones used by monks, nuns, and scholars ~1000 C.E. Lenses THERE ARE

More information

INSTRUCTORS GUIDE FOR THE HUMAN EYE AND VISION

INSTRUCTORS GUIDE FOR THE HUMAN EYE AND VISION INSTRUCTORS GUIDE FOR THE HUMAN EYE AND VISION Modern Miracle Medical Machines Dyan McBride Based on similar lessons developed by the Hartmut Wiesner & Physics Education Group, LMU Munich Our most important

More information

Converging Lenses. Parallel rays are brought to a focus by a converging lens (one that is thicker in the center than it is at the edge).

Converging Lenses. Parallel rays are brought to a focus by a converging lens (one that is thicker in the center than it is at the edge). Chapter 30: Lenses Types of Lenses Piece of glass or transparent material that bends parallel rays of light so they cross and form an image Two types: Converging Diverging Converging Lenses Parallel rays

More information

The Optics of Mirrors

The Optics of Mirrors Use with Text Pages 558 563 The Optics of Mirrors Use the terms in the list below to fill in the blanks in the paragraphs about mirrors. reversed smooth eyes concave focal smaller reflect behind ray convex

More information

Name: Date: Block: Light Unit Study Guide Matching Match the correct definition to each term. 1. Waves

Name: Date: Block: Light Unit Study Guide Matching Match the correct definition to each term. 1. Waves Name: Date: Block: Light Unit Study Guide Matching Match the correct definition to each term. 1. Waves 2. Medium 3. Mechanical waves 4. Longitudinal waves 5. Transverse waves 6. Frequency 7. Reflection

More information

Name Class Date. Use the terms from the following list to complete the sentences below. Each term may be used only once. Some terms may not be used.

Name Class Date. Use the terms from the following list to complete the sentences below. Each term may be used only once. Some terms may not be used. Assessment Chapter Test B Light and Our World USING KEY TERMS Use the terms from the following list to complete the sentences below. Each term may be used only once. Some terms may not be used. concave

More information

Wonders of Light - Part I

Wonders of Light - Part I 6. Wonders of Light - Part I Light : The fastest physical quantity, which is an electromagnetic radiation travelling with the speed of 3 0 8 m/s. SCHOOL SECTION 25 SCIENCE & TECHNOLOGY MT EDUCARE LTD.

More information

HUMAN EYE AND COLOURFUL WORLD

HUMAN EYE AND COLOURFUL WORLD HUMAN EYE AND COLOURFUL WORLD VERY SHORT ANSWER TYPE QUESTIONS [1 Mark] 1. Which phenomenon is responsible for making the path of light visible? Answer. Tyndall effect. 2. State one function of iris in

More information

Physics of the Eye *

Physics of the Eye * OpenStax-CNX module: m42482 1 Physics of the Eye * OpenStax This work is produced by OpenStax-CNX and licensed under the Creative Commons Attribution License 3.0 Abstract Explain the image formation by

More information

X rays X-ray properties Denser material = more absorption = looks lighter on the x-ray photo X-rays CT Scans circle cross-sectional images Tumours

X rays X-ray properties Denser material = more absorption = looks lighter on the x-ray photo X-rays CT Scans circle cross-sectional images Tumours X rays X-ray properties X-rays are part of the electromagnetic spectrum. X-rays have a wavelength of the same order of magnitude as the diameter of an atom. X-rays are ionising. Different materials absorb

More information

Human Eye Model OS-8477A

Human Eye Model OS-8477A Instruction Manual 02-3032A Human Eye Model OS-8477A 800-772-8700 www.pasco.com Table of Contents Contents Quick Start............................................................ Introduction...........................................................

More information

The eye & corrective lenses

The eye & corrective lenses Phys 102 Lecture 20 The eye & corrective lenses 1 Today we will... Apply concepts from ray optics & lenses Simple optical instruments the camera & the eye Learn about the human eye Accommodation Myopia,

More information

LIGHT-REFLECTION AND REFRACTION

LIGHT-REFLECTION AND REFRACTION LIGHT-REFLECTION AND REFRACTION Class: 10 (Boys) Sub: PHYSICS NOTES-Refraction Refraction: The bending of light when it goes from one medium to another obliquely is called refraction of light. Refraction

More information

Chapter: Sound and Light

Chapter: Sound and Light Table of Contents Chapter: Sound and Light Section 1: Sound Section 2: Reflection and Refraction of Light Section 3: Mirrors, Lenses, and the Eye Section 4: Light and Color 1 Sound Sound When an object

More information

always positive for virtual image

always positive for virtual image Point to be remembered: sign convention for Spherical mirror Object height, h = always positive Always +ve for virtual image Image height h = Always ve for real image. Object distance from pole (u) = always

More information

Optics: Lenses & Mirrors

Optics: Lenses & Mirrors Warm-Up 1. A light ray is passing through water (n=1.33) towards the boundary with a transparent solid at an angle of 56.4. The light refracts into the solid at an angle of refraction of 42.1. Determine

More information

MrN Physics Tuition in A level and GCSE Physics AQA GCSE Physics Spec P3 Optics Questions

MrN Physics Tuition in A level and GCSE Physics AQA GCSE Physics Spec P3 Optics Questions Q1. The diagram shows a ray of light passing through a diverging lens. Use the information in the diagram to calculate the refractive index of the plastic used to make the lens. Write down the equation

More information

2015 EdExcel A Level Physics EdExcel A Level Physics. Lenses

2015 EdExcel A Level Physics EdExcel A Level Physics. Lenses 2015 EdExcel A Level Physics 2015 EdExcel A Level Physics Topic Topic 5 5 Lenses Types of lenses Converging lens bi-convex has two convex surfaces Diverging lens bi-concave has two concave surfaces Thin

More information

Human Eye and Colourful World

Human Eye and Colourful World Human Eye and Colourful World Question 1: What is meant by power of accommodation of the eye? Answer: When the ciliary muscles are relaxed, the eye lens becomes thin, the focal length increases, and the

More information

WAVES: LENSES QUESTIONS

WAVES: LENSES QUESTIONS WAVES: LENSES QUESTIONS LIGHT (2016;1) Tim was looking into a convex mirror ball in his garden. Standing behind a small plant, he noticed that when he looked at the reflection of the plant in the convex

More information

7 = <» _1_. The Language of Physics. Summary of Important Equations. J_ Pi. \j?i rj

7 = <» _1_. The Language of Physics. Summary of Important Equations. J_ Pi. \j?i rj The Language of Physics Refraction The bending of light as it travels from one medium into another. It occurs because of the difference in the speed of light in the different mediums. Whenever a ray of

More information

Chapter 25: Applied Optics. PHY2054: Chapter 25

Chapter 25: Applied Optics. PHY2054: Chapter 25 Chapter 25: Applied Optics PHY2054: Chapter 25 1 Operation of the Eye 24 mm PHY2054: Chapter 25 2 Essential parts of the eye Cornea transparent outer structure Pupil opening for light Lens partially focuses

More information

The Human Brain and Senses: Memory

The Human Brain and Senses: Memory The Human Brain and Senses: Memory Methods of Learning Learning - There are several types of memory, and each is processed in a different part of the brain. Remembering Mirror Writing Today we will be.

More information

EYE STRUCTURE AND FUNCTION

EYE STRUCTURE AND FUNCTION Name: Class: Date: EYE STRUCTURE AND FUNCTION The eye is the body s organ of sight. It gathers light from the environment and forms an image on specialized nerve cells on the retina. Vision occurs when

More information

Refraction and Lenses

Refraction and Lenses Refraction and Lenses Name Q.(a) Figure shows a ray of light entering a glass block. (i) The angle of incidence in Figure is labelled with the letter i. On Figure, use the letter r to label the angle of

More information

Physics 1202: Lecture 19 Today s Agenda

Physics 1202: Lecture 19 Today s Agenda Physics 1202: Lecture 19 Today s Agenda Announcements: Team problems today Team 12: Kervell Baird, Matthew George, Derek Schultz Team 13: Paxton Stowik, Stacey Ann Burke Team 14: Gregory Desautels, Benjamin

More information

Chapter 36. Image Formation

Chapter 36. Image Formation Chapter 36 Image Formation Image of Formation Images can result when light rays encounter flat or curved surfaces between two media. Images can be formed either by reflection or refraction due to these

More information

Chapter 36. Image Formation

Chapter 36. Image Formation Chapter 36 Image Formation Notation for Mirrors and Lenses The object distance is the distance from the object to the mirror or lens Denoted by p The image distance is the distance from the image to the

More information

Types of lenses. Shown below are various types of lenses, both converging and diverging.

Types of lenses. Shown below are various types of lenses, both converging and diverging. Types of lenses Shown below are various types of lenses, both converging and diverging. Any lens that is thicker at its center than at its edges is a converging lens with positive f; and any lens that

More information

Unit Two: Light Energy Lesson 1: Mirrors

Unit Two: Light Energy Lesson 1: Mirrors 1. Plane mirror: Unit Two: Light Energy Lesson 1: Mirrors Light reflection: It is rebounding (bouncing) light ray in same direction when meeting reflecting surface. The incident ray: The light ray falls

More information

The Indian Academy Nehrugram DEHRADUN Question Bank Subject - Physics Class - X

The Indian Academy Nehrugram DEHRADUN Question Bank Subject - Physics Class - X The Indian Academy Nehrugram DEHRADUN Question Bank - 2013-14 Subject - Physics Class - X Section A A- One mark questions:- Q1. Chair, Table are the example of which object? Q2. In which medium does the

More information

Chapter 34: Geometrical Optics (Part 2)

Chapter 34: Geometrical Optics (Part 2) Chapter 34: Geometrical Optics (Part 2) Brief review Optical instruments Camera Human eye Magnifying glass Telescope Microscope Optical Aberrations Phys Phys 2435: 22: Chap. 34, 31, Pg 1 The Lens Equation

More information

Final Reg Optics Review SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

Final Reg Optics Review SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question. Final Reg Optics Review 1) How far are you from your image when you stand 0.75 m in front of a vertical plane mirror? 1) 2) A object is 12 cm in front of a concave mirror, and the image is 3.0 cm in front

More information

Solution. Class 10 - Science. Revision Test. Section A

Solution. Class 10 - Science. Revision Test. Section A Solution Class 10 - Science Revision Test Section A 1. (a) since resistances are in parallel R (b) Total current I 4.8 A (c) If I 1, I 2 and I 3 be the current through 2 respectively. Therefore, I 1 3

More information

Chapter 23. Mirrors and Lenses

Chapter 23. Mirrors and Lenses Chapter 23 Mirrors and Lenses Mirrors and Lenses The development of mirrors and lenses aided the progress of science. It led to the microscopes and telescopes. Allowed the study of objects from microbes

More information

Visual Perception. Readings and References. Forming an image. Pinhole camera. Readings. Other References. CSE 457, Autumn 2004 Computer Graphics

Visual Perception. Readings and References. Forming an image. Pinhole camera. Readings. Other References. CSE 457, Autumn 2004 Computer Graphics Readings and References Visual Perception CSE 457, Autumn Computer Graphics Readings Sections 1.4-1.5, Interactive Computer Graphics, Angel Other References Foundations of Vision, Brian Wandell, pp. 45-50

More information

Learning Intentions: P3 Revision. Basically everything in the unit of Physics 3

Learning Intentions: P3 Revision. Basically everything in the unit of Physics 3 Learning Intentions: P3 Revision Basically everything in the unit of Physics 3 P3.1 Medical applications of physics Physics has many applications in the field of medicine. These include the uses of X-rays

More information

Chapter 34 Geometric Optics (also known as Ray Optics) by C.-R. Hu

Chapter 34 Geometric Optics (also known as Ray Optics) by C.-R. Hu Chapter 34 Geometric Optics (also known as Ray Optics) by C.-R. Hu 1. Principles of image formation by mirrors (1a) When all length scales of objects, gaps, and holes are much larger than the wavelength

More information

12.1. Human Perception of Light. Perceiving Light

12.1. Human Perception of Light. Perceiving Light 12.1 Human Perception of Light Here is a summary of what you will learn in this section: Focussing of light in your eye is accomplished by the cornea, the lens, and the fluids contained in your eye. Light

More information

Slide 4 Now we have the same components that we find in our eye. The analogy is made clear in this slide. Slide 5 Important structures in the eye

Slide 4 Now we have the same components that we find in our eye. The analogy is made clear in this slide. Slide 5 Important structures in the eye Vision 1 Slide 2 The obvious analogy for the eye is a camera, and the simplest camera is a pinhole camera: a dark box with light-sensitive film on one side and a pinhole on the other. The image is made

More information

Chapter 18 Optical Elements

Chapter 18 Optical Elements Chapter 18 Optical Elements GOALS When you have mastered the content of this chapter, you will be able to achieve the following goals: Definitions Define each of the following terms and use it in an operational

More information

Sound. sound waves - compressional waves formed from vibrating objects colliding with air molecules.

Sound. sound waves - compressional waves formed from vibrating objects colliding with air molecules. Sound sound waves - compressional waves formed from vibrating objects colliding with air molecules. *Remember, compressional (longitudinal) waves are made of two regions, compressions and rarefactions.

More information

Chapter 23. Light Geometric Optics

Chapter 23. Light Geometric Optics Chapter 23. Light Geometric Optics There are 3 basic ways to gather light and focus it to make an image. Pinhole - Simple geometry Mirror - Reflection Lens - Refraction Pinhole Camera Image Formation (the

More information

INTERNATIONAL TURKISH HOPE SCHOOL ACADEMIC YEAR CHITTAGONG SENIOR SECTION BIOLOGY CO-ORDINATION CLASS 09 and 10 Name :... Date :...

INTERNATIONAL TURKISH HOPE SCHOOL ACADEMIC YEAR CHITTAGONG SENIOR SECTION BIOLOGY CO-ORDINATION CLASS 09 and 10 Name :... Date :... 1 P a g e 2 P a g e 3 P a g e 4 P a g e 5 P a g e 6 P a g e 7 P a g e 8 P a g e 9 P a g e 10 P a g e Name :... Date :... 11 P a g e Name :... Date :... 12 P a g e 13 P a g e 14 P a g e play important role

More information

Section 1: Sound. Sound and Light Section 1

Section 1: Sound. Sound and Light Section 1 Sound and Light Section 1 Section 1: Sound Preview Key Ideas Bellringer Properties of Sound Sound Intensity and Decibel Level Musical Instruments Hearing and the Ear The Ear Ultrasound and Sonar Sound

More information

Optical Systems. The normal eye

Optical Systems. The normal eye Optical Systems The normal eye The ciliary muscles can adjust the shape of the lens of the human eye. As the eye attempts to see objects at different distances, the muscles will adjust the focal length

More information

CHAPTER 18 REFRACTION & LENSES

CHAPTER 18 REFRACTION & LENSES Physics Approximate Timeline Students are expected to keep up with class work when absent. CHAPTER 18 REFRACTION & LENSES Day Plans for the day Assignments for the day 1 18.1 Refraction of Light o Snell

More information

ID: A. Optics Review Package Answer Section TRUE/FALSE

ID: A. Optics Review Package Answer Section TRUE/FALSE Optics Review Package Answer Section TRUE/FALSE 1. T 2. F Reflection occurs when light bounces off a surface Refraction is the bending of light as it travels from one medium to another. 3. T 4. F 5. T

More information

Chapter Introduction. Chapter Wrap-Up. and the Eye

Chapter Introduction. Chapter Wrap-Up. and the Eye Chapter Introduction Lesson 1 Lesson 2 Lesson 3 Sound Light Chapter Wrap-Up Mirrors, Lenses, and the Eye How do sound and light waves travel and interact with matter? What do you think? Before you begin,

More information

BHARATIYA VIDYA BHAVAN S V M PUBLIC SCHOOL, VADODARA QUESTION BANK

BHARATIYA VIDYA BHAVAN S V M PUBLIC SCHOOL, VADODARA QUESTION BANK BHARATIYA VIDYA BHAVAN S V M PUBLIC SCHOOL, VADODARA QUESTION BANK Ch Light : Reflection and Refraction One mark questions Q1 Q3 What happens when a ray of light falls normally on the surface of a plane

More information