G10 Reflection of Light

Question 1

Light ordinarily travels in straight line path called ray.
In order to represent light, rays are used.
Rays are lines with an arrow head at its end.
The arrow head tells the direction where the light ray is going.

Question 2

imaginary line perpendicular to the surface

Answer 2

Normal line

Question 3

is the angle which an incident ray makes with normal line

Answer 3

The angle of incidence (𝜃i)

Question 4

is the angle which the reflected ray makes with the normal

Answer 4

The angle of reflection (𝜃r)

Question 5

The angle of incidence and the angle of reflection is always measured from the normal line

Question 6

The idea that the path which light travels is the one that uses the shortest time is called _.
This means that in order for light to go from one point to another, it takes the shortest and most efficient path available to it.

Answer 6

Fermat’s Principle of Least Time

Question 7

states that the incident and reflected rays lie in the same plane with the normal and that the angle of reflection equals the angle of incidence, 𝜃i = 𝜃r

Answer 7

law of reflection

Question 8

Types of Reflection

Answer 8

Diffuse Reflection

Specular Reflection

Question 9

happens when light is reflected into multiple directions.
This is true when light hits a rough surface.
Objects that might appear smooth to touch but still performs _ _ are actually microscopically rough. eg. eggshell

Answer 9

Diffuse reflection

Question 10

happens when light is reflected at only one path.
This is true when light hits a smooth surface.
Microscopically smooth surface are good reflectors of light. e.g. mirrors

Answer 10

Specular reflection

Question 11

is a smooth, flat reflecting surface.
It creates images that are located on the same distance as the object from the mirror and with the same height but are inverted from left to right.

Answer 11

plane mirror

Question 12

An imaginary line passing through the center of the sphere at the exact center of the mirror.

Answer 12

Principal Axis

Question 13

The point on the mirror’s surface where the principal axis meets the mirror

Answer 13

Vertex

Question 14

The point in the center of the sphere from which the mirror was sliced

Answer 14

Curvature (C)

Question 15

Halfway between the center of curvature and vertex

Answer 15

Focal point (F)

Question 16

The distance between the vertex and the focal point

Answer 16

Focal length (f)

Question 17

is a curved mirror wherein the reflecting surface is bulging towards the viewer.
This mirror focuses light away from the focal point that is why it is called diverging mirror.

Answer 17

convex mirror

Question 18

In order to find where an image will be located if an object is placed in front of a mirror, a technique called _ _ is used.
Different rays are used to represent the light rays coming from the object.

Answer 18

ray diagramming

Question 19

a reference ray starting from the object going parallel to principal axis is drawn. It reflects through the focal point, F, after it hits the mirror

Answer 19

principal ray

Question 20

second reference ray goes through F and then goes parallel to principal axis after hitting the mirror

Answer 20

focal ray

Question 21

third reference ray goes through C then goes back along itself through C

Answer 21

central ray

Question 22

Since the F and C of a convex mirror are situated behind the mirror’s surface, dotted lines are extended along the reflected rays to points behind the mirror. The intersection of two or more rays locates the image.

Question 23

location
orientation
size
type

Answer 23

Location is at the back the mirror

Orientation is upright

Size is smaller (or diminished)

Type is virtual

Question 24

It is possible to mathematically calculate where an image will show up if distance of the object is known. It is also possible to know the radius of curvature of a mirror given the location of object and the image.

Answer 25

p – object’s distance from the mirror
q – image’s distance from the mirror
f – focal length

Question 26

mirror equation

Answer 26

1/p + 1/q = 1/f

Question 27

Units for distances and focal length should be consistent.

Question 28

The magnification of an image can be computed either by using the height of the image and the object or their distances. A positive M means that image is upright and virtual and a negative value means it is inverted and real.

Answer 28

M=h’/h or q/p

Question 29

is a curved mirror wherein the reflecting surface is on the inner surface of the sphere so that the center of the mirror sinks away from the viewer

Answer 29

concave mirror

Question 30

First ray: From the object parallel to the principal axis and will be reflected to the focal point.

Question 31

Second ray: From the object through the focal point and is reflected parallel to the principal axis.

Question 32

Third ray: From the object through the central point and will be reflected back to the central point.

Question 33

The point where the rays intersect is where the image will appear.