8.2 Geometrical Optics

Question 1

geometrical optics

Answer 1

describes the behaviour of light at the boundary of a medium

explains reflect and refraction and the application of mirrors and lenses

Question 2

rectilinear propogation

Answer 2

the tendency light to travel in a straight line when travelling through a homogenous medium

Question 3

reflection

Answer 3

the rebounding of incident light waves at the boundary of a medium

the light waves travel BACK through the first medium rather than absorving into the second medium

Question 4

law of reflection

Answer 4

incident angle = reflected angle

both measured from the normal line (perp. to the boundary of the medium)

Question 5

all angles in optics are measured from which reference line

Answer 5

the normal line (perpendicular to the medium boundary)

NOT from the surface of the medium

Question 6

what type of images to plane mirrors form

Answer 6

virtual images

Question 7

plane mirrors

Answer 7

flat reflective surface

Question 8

virtual images

Answer 8

form BEHIND the mirror

image appears to be the same distance behind the mirror as the object is in front of the mirror

Question 9

real image

Answer 9

form on the same side of the mirror as the actual object

always inverted

Question 10

2 varieties of spherical mirrors

Answer 10

concave

convex

Question 11

center of curvature

Answer 11

the center of the spherically shaped mirror IF it extended into a complete sphere

Question 12

radius of curvature

Answer 12

the distance between the center of curvature and the mirror

Question 13

concave mirror

Answer 13

the center of curvature is located in front of the mirror

Question 14

convex mirror

Answer 14

The center of curvature is located behind the mirror

Question 15

concave mirrors cause parallel incident light rays to:

Answer 15

converge

Question 16

convex mirrors cause parallel incident light rays to:

Answer 16

diverge

Question 17

focal point (F)

Answer 17

the point at which all parallel beams are “focussed” after reflection in the mirror

Question 18

focal length (f)

Answer 18

the distance between the focal point (F) and the mirror

Question 19

magnification (m)

Answer 19

a dimensionless value that is the ration of the image distance to the object distance

also gives the ratio of the size of the image to the size of the object

Question 20

if m < 0

Answer 20

the image is inverted (upside down)

Question 21

if m > 0

Answer 21

the image is upright

Question 22

if |m| < 1

Answer 22

the image is reduced

Question 23

if |m| > 1

Answer 23

the image is enlarged

Question 24

if |m| = 1

Answer 24

the image is the same size as the object

Question 25

optics equation

Answer 25

Question 26

magnification equation

Answer 26

Question 27

refraction

Answer 27

the bending of light as it passes from one medium to another and changes speeds

Question 28

index of refraction for a given medium (equation)

Answer 28

Question 29

snell's law

Answer 29

Question 30

critical angle

Answer 30

when the refracted angle equals 90 degrees the refracted light ray passes along the interface between the 2 media and never escapes the medium

Question 31

how to calculate the critical angle

Answer 31

use snells law and let the second angle = 90 sin (90) = 1

Question 32

total internal reflection

Answer 32

a phenomenon in which all the light incident on a boundary is reflected back into the original material Results when the incident angle is greater than the critical angle

Question 33

lenses vs mirrors

Answer 33

lenses REFRACT light mirrors REFLECT light

Question 34

lenses have two surfaces that affect light path

Answer 34

First surface: the surface when light enters from the air into the glass lens/object Second surface: the surface where light exits the glass lens back into the air

Question 35

converging lens

Answer 35

thicker at the center used to see things up close

Question 36

diverging lens

Answer 36

thinner at the center used to see things far away

Question 37

lensmaker's equation

Answer 37

f = focal length n = index of refraction of the lens material R1 = radius of curvature of the first lens surface R2 = radius of curvature of the second lens surface

Question 38

lens power (equation)

Answer 38

Question 39

hyperopia

Answer 39

farsightedness unable to see things close to the eye

Question 40

myopia

Answer 40

nearsightedness unable to see things far away

Question 41

multiple lens systems: lenses in contact

Answer 41

A series of lenses with negligible distances between them behave as a single lens

Question 42

multiple lens systems: lenses not in contact

Answer 42

The image of one lens becomes the object of another lens the image of the LAST lens is considered the “image of the system”

Question 43

magnification for a system of lenses not in contact (equation)

Answer 43

Question 44

spherical aberration

Answer 44

an optical problem that occurs when all incoming light rays end up focusing at different points after passing through a spherical surface results in an image with blurry edges

Question 45

speed if light in a VACUUM...

Answer 45

is constant for all wavelengths

Question 46

in mediums other than a vacuum...

Answer 46

different wavelengths travel at different speeds

Question 47

dispersion

Answer 47

when various wavelengths of light separate from each other

Question 48

what CHANGES when a wavelength enters a medium with a difference index of refraction?

Answer 48

the WAVELENGTH changes

Question 49

what DOES NOT CHANGE when a wavelength enters a medium with a difference index of refraction?

Answer 49

the FREQUENCY stays the same

Question 50

chromatic aberration

Answer 50

the failure of a spherical lens to focus all **colors** to the same point due to dispersion