Chapter 5Chapter 5The Law of reflection allows mirrors to form images

Section 5. 1 – The Ray Model of Section 5. 1 – The Ray Model of LightLight

The ray model of light can The ray model of light can be used to understand be used to understand how light moves in how light moves in straight lines, reflects off straight lines, reflects off mirrors and refracts mirrors and refracts through lenses.through lenses.

In order for you to see an In order for you to see an object, it must reflect object, it must reflect some light back to your some light back to your eyes.eyes.

Sir Isaac Newton believed Sir Isaac Newton believed that light is a stream of that light is a stream of fast-moving, unimaginably fast-moving, unimaginably tiny particles.tiny particles.

A ray is an imaginary line showing the direction in which light is traveling

Transparent Materials – allows light to pass freely Transparent Materials – allows light to pass freely through it. Only a small amount of light is through it. Only a small amount of light is absorbed and reflected.absorbed and reflected.

Translucent Materials – most light rays get Translucent Materials – most light rays get through, but are scattered in all directions. They through, but are scattered in all directions. They do not allow objects to be seen distinctly.do not allow objects to be seen distinctly.

Opaque Materials – prevents any light from passing Opaque Materials – prevents any light from passing through it. It only absorbs and reflects light.through it. It only absorbs and reflects light.

Rectilinear Rectilinear Propagation – light Propagation – light travels in a straight travels in a straight line.line.

The distance from a The distance from a light source affects light source affects the size of the the size of the shadow that an shadow that an object makes.object makes.

The closer an object The closer an object is to a light source, is to a light source, the smaller the the smaller the shadow.shadow.

Page 175, Questions 1 -4

Reflection – 2 different Reflection – 2 different typestypes

1. Specular Reflection – reflection from 1. Specular Reflection – reflection from a mirror-like surface, which produces an a mirror-like surface, which produces an image of the surroundings.image of the surroundings.

Specular Reflection

2. Diffuce Reflection – reflection from a 2. Diffuce Reflection – reflection from a rough surface, which does not produce rough surface, which does not produce a clear image but instead allows you to a clear image but instead allows you to see what is on the surface.see what is on the surface.

Diffuse reflection allows you to read print on a page. The black ink, on a white page, will absorb most of the light. The white page will reflect rays which go out in all directions.

An example of Diffuce Reflection

Page 177, Questions 1 - 3

Law of ReflectionLaw of ReflectionThe angle of reflection of a light ray is The angle of reflection of a light ray is equal to the angle of incidence, or the equal to the angle of incidence, or the angle at which the ray strikes the angle at which the ray strikes the reflecting surface.reflecting surface.

RefractionRefractionThe bending of light, when it travels The bending of light, when it travels from one medium to another.from one medium to another.

Light being refracted through a prism

Page 181, Questions 1 – 3Read Pages 181 – 182Page 182, Questions 1 - 2

Angle of incidence (i) Angle of Reflection ( r )Angle of Refraction (R)

Core Lab – Follow that Core Lab – Follow that Refracted RayRefracted Ray

Lab write up – page 184 & 185Lab write up – page 184 & 185

Questions 3 – 8 page 185Questions 3 – 8 page 185

Page 187, Questions 1 – 11Page 171, Foldable - 1st 2 sections

Section 5.2 Images in Plane Section 5.2 Images in Plane MirrorsMirrors

All mirrors reflect light All mirrors reflect light according to the law of according to the law of reflection.reflection.

A flat smooth mirror is A flat smooth mirror is called a plane mirror.called a plane mirror.

The mirror on the wall, in The mirror on the wall, in your bathroom, is your bathroom, is probably a plane mirror.probably a plane mirror.

Using Mirrors to Form Images

Plane MirrorsPlane MirrorsPlane mirrors form an image that is upright and Plane mirrors form an image that is upright and appears to be as far behind the mirror as the appears to be as far behind the mirror as the object is in front of it.object is in front of it.

Left and right appear to be reversed in a plane Left and right appear to be reversed in a plane mirror.mirror.

Page 191, Questions 1 - 3

Core Lab – Demonstrating the Law Core Lab – Demonstrating the Law of Reflectionof Reflection

Lab Write Up – Page 192 & 193Lab Write Up – Page 192 & 193

Analyze Questions: 1 – 3Analyze Questions: 1 – 3

Conclude and Apply Questions: 1 -3 Conclude and Apply Questions: 1 -3

Lab Write Up – Page 194Lab Write Up – Page 194

Analyze Questions: 1 – 2Analyze Questions: 1 – 2

Conclude and Apply Questions: 3 – 4Conclude and Apply Questions: 3 – 4

Page 195, Questions: 1 – 6Page 195, Questions: 1 – 6

Foldable – Section 3Foldable – Section 3

Section 5. 3 – Images in Curved MirrorsSection 5. 3 – Images in Curved Mirrors

A concave mirror is a mirror that curves inward.A concave mirror is a mirror that curves inward.

Light reflecting off a concave mirror meet at a single Light reflecting off a concave mirror meet at a single point called the focal point.point called the focal point.

Light rays that come together are called converging rays.Light rays that come together are called converging rays.

Flashlights, car headlights, and telescopes, are a few Flashlights, car headlights, and telescopes, are a few applications of concave mirrors.applications of concave mirrors.

Concave Mirrors

The image formed by a concave The image formed by a concave mirror depends on the location mirror depends on the location

of the object.of the object.

A ~ object outside 2 focal point lengths; image is smaller and inverted and real

B ~ object is between F and 2F; image is larger and inverted and real

C ~ object is between F and mirror; image is larger and upright and virtualPage 202, Questions: 1 - 4

Convex MirrorsConvex Mirrors

A convex mirror A convex mirror is a mirror that is a mirror that curves outwards. curves outwards.

Reflected rays Reflected rays from a convex from a convex mirror diverge mirror diverge and do not meet.and do not meet.

The image formed by a convex The image formed by a convex mirror have these characteristics:mirror have these characteristics:

Image is smaller than the Image is smaller than the object.object.

The image distance is The image distance is smaller than the object smaller than the object distance.distance.

The image is upright.The image is upright.

The image is virtual.The image is virtual.

More objects can be seen More objects can be seen in a convex mirror than in a in a convex mirror than in a plane mirror.plane mirror.

Using Lenses to Form ImagesUsing Lenses to Form Images

A lens is a piece of A lens is a piece of transparent material that can transparent material that can bend, or refract, light rays in bend, or refract, light rays in useful ways to help form a useful ways to help form a well-focused image.well-focused image.

A lens can be concave or A lens can be concave or convex.convex.

Concave LensesConcave Lenses

Concave lenses are thinner in the middle than at the edge.Concave lenses are thinner in the middle than at the edge.

Concave lenses cause light rays to diverge.Concave lenses cause light rays to diverge.

Concave lenses produce images that are upright and Concave lenses produce images that are upright and smaller than the object.smaller than the object.

Concave lenses are sometimes used in eyeglasses and Concave lenses are sometimes used in eyeglasses and telescopes.telescopes.

Convex LensesConvex Lenses

Convex lenses are thicker in the middle Convex lenses are thicker in the middle than at the edge.than at the edge.

Convex lenses cause light rays to Convex lenses cause light rays to converge.converge.

When parallel rays strike a convex lens When parallel rays strike a convex lens they come together at the focal point.they come together at the focal point.

A magnifying glass is a good example A magnifying glass is a good example of a convex lens.of a convex lens.

Focal length in Convex LensesFocal length in Convex Lenses

The distance from the centre of the lens The distance from the centre of the lens to the focal point is called the focal to the focal point is called the focal length.length.

The type of image a convex lens The type of image a convex lens forms depends forms depends on where the object is relative to on where the object is relative to the focal point.the focal point.

Page 206, Questions: 1 – 3Page 209, Questions: 1 – 12Foldable – Remaining Sections

Chapter Review Questions, Page 210