Chapter 5 Review

Question 1

What is the particle model of light?

Answer 1

The particle model was create by Sir Isaac Newton, and imagines light to be a stream of tiny particles traveling in lines until they reach the eye.

Question 2

What is the ray model of light?

Answer 2

The ray model of light represents light as a straight line that shows the direction of the light wave’s travels.

Question 3

What is optics?

Answer 3

Optics is how light moves.

Question 4

What does your vision depend upon?

Answer 4

Your vision depends upon the amount of light entering your eye.

Question 5

How does matter affect light?

Answer 5

The type of matter in an object determines the amount of light it absorbs, reflects, and transmits.

Question 6

What does transparent mean?

Answer 6

Transparent is when light can travel through a matter freely. Window glass is transparent when you can see clearly through it.

Question 7

What does translucent mean?

Answer 7

Translucent is when most light rays get through but they are scattered in many directions. Objects cannot be seen clearly, like through frosted glass.

Question 8

What does opaque mean?

Answer 8

Opaque means light cannot pass through the matter, like a wall. The matter absorbs and reflects light, but no light passes through.

Question 9

How is a shadow formed?

Answer 9

A shadow is formed because the light rays are blocked by the object

Question 10

How can the size of a shadow be determined?

Answer 10

The size of a shadow is a relationship between the distance of the object from its light source.

Question 11

If you have two shadows from the same shape object, what can you tell about the distance between the object and the light source?

Answer 11

The larger shadow is cast by the object that is closer to the light source.

Question 12

Why is paper not a mirror?

Answer 12

Paper is not a mirror because microscopically it is a rough surface and a mirror must be totally smooth to reflect all light.

Question 13

what is an incident ray?

Answer 13

An incident ray is the initial ray of light coming in towards the mirror.

Question 14

What is a reflected ray?

Answer 14

A reflected ray is the ray that bounces off the mirror.

Question 15

How are the angles of incident and reflected rays similar?

Answer 15

The angle of incidence and reflection are equal.

Question 16

What is the law of reflection?

Answer 16

The law of reflection proves that the angle of incidence and reflection will always be the same.

Question 17

If a light ray hits a mirror at a 60 degree angle, what will the angle of reflection be?

Answer 17

The angle of reflection will be 60 degrees.

Question 18

What is refraction?

Answer 18

Refraction is when a ray or wave is bent.

Question 19

How can light be refracted?

Answer 19

Light can be refracted when it enters a new medium, such as water.

Question 20

Why is the light ray refracted in water?

Answer 20

Light will be refracted because it slows down in the new medium.

Question 21

What is ‘normal’

Answer 21

normal’ is a right angled line meeting the surface it is an imaginary line drawn perpendicular to a reflecting or refracting surface at the point where an incident ray strikes the surface.

Question 22

What happens when light refracts through air?

Answer 22

When some air is hotter than other spots we see a mirage.

Question 23

What creates the illusion of water in a mirage?

Answer 23

The water is created by the hotter air near the ground bends the light as it gets to the ground and it reflects the sky image.

Question 24

Why does a fish in the water appear to be closer to the surface than it really is?

Answer 24

Your brain assume that the light has not been refracted, so the image is misinterpreted.

Question 25

What is a plane mirror?

Answer 25

A plane mirror is a smooth mirror, usually found in a home.

Question 26

How do you know your reflection is in a plane mirror?

Answer 26

In a plane mirror, your reflection will be equal distance into the mirror as you are away from the mirror, the orientation will be the same, and your size will be the same

Question 27

What is the only difference in the reflection in a plane mirror?

Answer 27

Your image is reversed.

Question 28

What is a concave mirror?

Answer 28

A concave mirror curves inwards.

Question 29

What is a focal point?

Answer 29

The focal point is the place where all the reflected rays meet.

Question 30

What is converging?

Answer 30

When all the rays meet at one point they are said to be converging — joining

Question 31

how does a concave mirror change the image?

Answer 31

From a distance the image is small and upside down, as the item gets closer it stays upside down but gets larger. As the item gets past the focal point, the image becomes larger than in real life and goes upright.

Question 32

what are some uses for a concave mirror?

Answer 32

Concave mirrors are used in flashlight, car headlights and lighthouses because the focal point concentrates the light. Shaving and make up mirrors enlarge the image to give greater detail

Question 33

What is a convex mirror?

Answer 33

A convex mirror curves outwards.

Question 34

How are the light rays reflected in a convex mirror?

Answer 34

The light rays are reflected as if the focal point was behind the mirror.

Question 35

How do object appear in a convex mirror?

Answer 35

Convex mirrors make the object appear smaller, and more objects can be seen in the mirror.

Question 36

Where are convex mirrors used?

Answer 36

Convex mirrors are used in security mirrors in stores and libraries. They widen the view in vehicle side mirrors.d

Question 37

What happens to light when it enters a new denser material?

Answer 37

When light enters a denser material it bends or refracts toward the ‘normal’

Question 38

What happens when light travels into less dense material?

Answer 38

When light travels to less denser material it bends or refracts away from ‘normal’

Question 39

What is a lens?

Answer 39

A lens is a transparent material that refracts the light in such a away as to converge or diverge parallel light rays.

Question 40

What does the shape of the lens change?

Answer 40

The shape of the lens changes the image that is formed.

Question 41

How are lenses like mirrors?

Answer 41

Lenses can be convex or concave

Question 42

What is a concave lens?

Answer 42

A concave lens is thinner in the middle than on the edge.

Question 43

How do rays of light behave when they go through a concave lens?

Answer 43

Through a concave lens, light rays do not meet at a focal point. The image is upright and smaller than the actual object.

Question 44

When are concave lenses used?

Answer 44

Concave lenses are used in some eyeglasses and some telescopes, usually combined with other lenses.

Question 45

What is a convex lens?

Answer 45

A convex lens is thicker in the middle than at the edge.

Question 46

How do light rays behave through a convex lens?

Answer 46

Through a convex lens, light rays converge at a focal point, the image will be flipped upside down. (inverted)

Question 47

What happens to light that passes through the direct center of a convex lens?

Answer 47

The light passing through the direct center of a convex lens does not refract.

Question 48

What is focal length?

Answer 48

Focal length is the distance from the centre of the lens or mirror to the focal point.

Question 49

What are the three mathematical rules for a convex lens?

Answer 49

1. If the object is +2focal lengths away from the lens, the object is smaller and inverted. 2. If the object is between 1-2 focal lengths away from the lens, the object is larger and still inverted, 3. If the object is less than one focal length away, the object seems to be on the other side of the lens and is upright

Question 50

What happens in a convex lens if the object is at the focal point of the lens?

Answer 50

If the object is at the focal point of the convex lens, there appears to be no image