properties of light and reflection

Question 1

medium

Answer 1

the substance through which light travels (air, water)

Question 2

ray

Answer 2

a straight line with an arrowhead that shows the direction in which light waves are travelling

Question 3

ray tracing

Answer 3

using rays to predict the location, size, and shape of the image of an opaque object

Question 4

2 parts of fermat’s principle

Answer 4

light follows the shortest straight line between two points

when light reflects into the same medium from which it originated, its speed will remain constant

Question 5

reflection

Answer 5

change in direction of a light ray when it bounces off a surface

Question 6

incident ray

Answer 6

a ray of light that travels from a light source toward a surface

Question 7

angle of incidence

Answer 7

the angle between the incident ray and the normal

Question 8

normal

Answer 8

a line that is perpendicular to a surface where a ray of light meets the surface

Question 9

reflected ray

Answer 9

a ray that begins at a point where the incident ray and the normal meet

Question 10

angle of reflection

Answer 10

the angle between the reflected ray and the normal

Question 11

3 laws of reflection

Answer 11

incident ray, normal, and reflected ray lie on the same surface
angle reflection (r) = angle of incidence (i)
reflected ray and incident ray are on opposite sides of the normal

Question 12

how to draw ray diagrams: step 1

draw the _____ using a ruler

Answer 12

incident

Question 13

how to draw ray diagrams: step 2
at the contact point where the incident ray hits the surface, draw a ______ by measuring a __ degree angle with a protractor

Answer 13

normal / 90

Question 14

how to draw ray diagrams: step 3
measure the longest ________ between the incident ray and the _____. make a mark to indicate the same angle on the other side of the normal. this is the ____________

Answer 14

angle of incident (i) / normal / angle of reflection

Question 15

how to draw ray diagrams: step 4

draw the _________ from the contact point through the mark using a ruler

Answer 15

reflected ray

Question 16

how to draw ray diagrams: step 5

what 5 things do you label?

Answer 16

incident ray
reflected ray
angle of incidence (i)
angle of reflection (r)
normal

Question 17

why do we see objects in mirrors?

Answer 17

light rays are reflected off the objects and back to your eye

Question 18

plane mirror

Answer 18

a mirror with a flat, reflective surface

Question 19

step 1 of reflections:

when a light shines on the object, it reflects off all the points on the object in _________.

Answer 19

all directions

Question 20

step 2 of reflections:

the rays reach the mirror, follow the ___________, and reflect toward your eye.

Answer 20

laws of reflection

Question 21

step 2 of reflections:
even though the rays are reflected, your brain assumes light rays travel in a straight line, and treats them as if ____________

Answer 21

they had come form a point behind the mirror

Question 22

how do we find out where the eye “sees” the image?

Answer 22

extend the reflected rays until they meet at a point behind the mirror

Question 23

what kind of image forms? (L.O.S.T.)

Answer 23

location
orientation
size
type of image

Question 24

location (L.O.S.T.)

Answer 24

image distance (distance between mirror and image) = object distance (distance between mirror and object) 
image distance can be the same as, farther than, or closer than the object distance

Question 25

orientation (L.O.S.T.)

Answer 25

upright, inverted, or reversed

Question 26

size (L.O.S.T.)

Answer 26

image size = object size

size can be the same size, larger than, or smaller than the object

Question 27

type of image (L.O.S.T.)

Answer 27

virtual image (forms behind mirror) or real (forms in front of mirror)

Question 28

step one of ray diagram

Answer 28

incident ray from top of object horizontally to mirror surface, reflects back, extends behind mirror

Question 29

step two of ray diagram

Answer 29

repeat 1, except from other points on object

Question 30

step three of ray diagram

Answer 30

reflected ray from image to eye from all points

Question 31

step four of ray diagram

Answer 31

draw normal where reflected rays (see 3) meets mirror surface

Question 32

step five of ray diagram

Answer 32

draw incident ray from top of object to mirror (at normals)

Question 33

step six of ray diagram

Answer 33

measure incident and reflected ray angles

Question 34

what are the characteristics of images in plane mirrors?

Answer 34

same size, same distance, same orientation; virtual image

Question 35

lateral inversion

Answer 35

the apparent reversal of the mirror image’s left and right when compared with the object