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MSU / Industrl & Systems Engineering / ISE 112304 / What is the difference between a real image and a virtual image?

# What is the difference between a real image and a virtual image? Description

##### Description: This study guide covers all the material gone over for chapters 23-25 and any other material that will best tested on during Test 2.
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CHAPTER 23

## What is the difference between a real image and a virtual image? WEEK 6

* Geometrical Optics:

· Real Images: images that can be projected onto a screen,

· Virtual Images: images can not be projected, you must look into the mirror, through the lense to see these.

## What is the formula for image distance? If you want to learn more check out What does it mean when price elasticity is less than one?

)

· Object distance (de): the distance of the object to the mirror or lense. image distance (di): distance from the image to the mirror or lense.

· Focus point (F): the point where an image would form if the object was really far away.

## What is mean by virtual image? *Fiq. 23-14

· Focal length (F): the distance from the mirror llense to the focus point. We also discuss several other topics like Is property owned before marriage a community property?

· Center of Curvature point (C): the center curvature of the

mirror llense Radius of Curvature (s): the distance from the mirrorllense We also discuss several other topics like What mechanism applied the bill of rights to the states?

to "C".

fer

or

r=2f

· Spherical Aberation : a circular / spherical curved mirror or lense will not produce a true focus. A parabolic curvature is required for a true focus.

* Fig. 23-13, 23-14 We also discuss several other topics like How did ammonites evolve?

ex

| • Convex Mirrors: images will be upright, smaller, and

virtual.

· both di and F are negative - Ex: security mirrors, blind spot mirrors, passenger

side mirrors (Figs. 23-19*, 20,11B)

· Concave Mirrors:

.f is positive We also discuss several other topics like What are sticky ends and why are they important?

(1) if the object is further away from the focus then the

image will be real and inverted (2) 1f the object is closer than the focus then the image

will be virtual, upright, and magnified.

· Ex: makeup mirror (com pact) or satillite dishes (Figs. 23-15*, 17*, & 11A)

* The Mirror Cor Thin Lense) Equation

=

1

* negative for inverted images *

di

uds If you want to learn more check out What separates the archean from the proterozoic periods?

Magnification Equation

m= hi is height of image (can be negative) — L ho height of objects

m=-di

CHAPTER 233

CHAPTER 23

WEEK 6

* HOMEWORK PROBLEM

(a) what type of mirror ?: Concave

(Convex can only make (-) m)

12. do = 2.00 cm

m = +4

(b) r = ?

f=?

me-di – 4 =-di – di = -8

do

2

f=2.66cm

do

di

2

-8

1=2f

r=2(2.66) =15.33cm

* RAY DIAGRAMS

(1) Rays parallel to axis will reflect through "F" (2) Rays coming from or passing through "F" will reflect

parallel to the axis (3) Rays coming from or passing through "C" will reflect

| straight back on themselves. * where the 3 intersect is the location of the image

SOU

CHAPTER 23

WEEK 6

OVO

I

F

HOMEWORK EX. RAY

SO

* In the equation

pl

> use "x" button!

exo

example 1 - -

→-8x' – 16x' = answer (x') = f

8

16

* The Index of Refraction (n):

- A constant of proportionality for determining how

fast the light will travel in the medium.

7 speed of light in free space (3x108m/s)

n느

Vy speed of light in the new medium

v=Cl

* See table 23-1 for n valves

EXAMPLE: Find the speed of light in water.

nwater = 1.33

c=3x108

v: 3*108 = 2.26*108 v=?

1.33

normal

*recall: the law of refraction

sinora vran sino, Vi ni air

water sin Or a no

sino ni

--

0

* SNELL'S LAW:

no sin or= n; sino;

EXAMPLE: Light strikes the water at a 53° with respect

to the normal. At what angle does the light travel in the water?

nr =1.33

ni=1

nsino = n; sino;

(1.33) sinos = (1) (sin 53) = 36.90

1.33

1.33 * always a smaller angle inste inside of more

dense material of

Total Internal Reflection: tot

- This can happen when...

(1) When the incident light is inside of the more

dense material. Cnians) (2) The incident angle must be greater than the

critical angle.

* Critical angle: the incident angle that produces a

refracted angle of 90°.

ni sin O; = no Sin Or ni Sin c = ns sin 90

sinoc = no (sin 90)

Soup

• sinoc = nr

critical

angle

StudySoup

EXAMPLE: Find the critical angle for the air to water interface.

nos air = 1

o water = 1.33

sin c = 1 = sino

48.75 0

1.33

n; = water = 1.33

sinOe = sin" (2) - 48.750)

1.33

Study

StudySoup

CHAPTER 24

WEEK 7

* How Wavelength (X) is Affected in Refraction

recall: siner

sino; V Xi8

sino sinoi

ni

* see Fig. 3

Xralini

* Mirages: refraction when the index of refraction is

gradually changing throughout the medium. It causes the light waves to curve.

- Fig. 24-4

* INTERFERENCE AND DEFRACTION

- Young's Double Slit Experiment:

The constructive interference pattern occurs at:

sin ,mX

/ d distane between the slits

m= 01,23... the 1st spots after m=0 tan Om = *m

the center spot slits

screen

* These m=2

spots are also 03-bm1 T

called"Fringes" 2 -m=8 1

m =2 m=1 M=0 M-1

00000

to

tanO2 = 7

m2

* Fig. 24-5,6,87*

- The destructive interference pattern (dark spots)

Occurs at: sino = (m + 2 x

* HOMEWORK PROBLEM

x1 = 0.086 m

tan =

= 0.7490 sin Om= masin 02 = 2 2 2

Study

ay Soup

d = 0.048 mm L = 6.5 m

.= 0.7490

Sin (0.749) = X = X = 6.276 x 1070

0.000048 X = 627.6*10-9 nm

v=lf F = 4.78*1014 Hz

* Dispersion: when light is broken up into its constituant

wavelengths Ceolocs).

CHAPTER 24

WEEK 8

* Dispersion:

- Methods doing this include double or single-slit

interference, defraction grating & refraction, - Dispersion from refraction occurs through prisms. water droplets, crystals, diamonds, ect. There is a

different index of refraction for different wavelengths (colors).

* See Figs. 24-13,14,15,16

Study

* Single SlitInterference:

screen

>dark spot

liane

central maximum => ZX1 *] => 20, > dock spot

- Diffraction by a single slit or disk will produce a constructive

interference pattern. 1) 8 This pattern is both lightest and widest at the

center (central maximum). 2) The minimums, means destructive interference or

dack spots, occur at:

m= 1,2,3... (no o)

lit width

SOP

tano = x

3) Constructive interference (maximums + fringes/

bright spots) will occur at the center and at:

sino = (m+ (2) »

HALA

* HOMEWORK PROBLEM

sine= MA

24. D = 1 mm = 0.001m

X = 450 mm central max => m= 1 2xq = ? L = om

Sino = (450*10-9)

0.001 sin 01 ► 01 = 0.025783°

tan. = X. → L (tana) = X1

X1 = 0.0027 m 2x1 = 0.0054m

* Small Angle Approm.

Studs

sino tano * DON'T USE THIS!!

Stud

WEEK 8

* Diffraction Grating: this is a transparent material

that is composed of many parallel lines (slits/openings). - Number of lines: 1000 lines/cm - 18000 lines/cm - The interference patterns are similar to the

double slit patterns. - The maximums (const interferences occur at:

i

d = 1

# of lines per m

sin = mx

di distance between

the slits

tano = X

m = 0,1,2,3...

* HOMEWORK PROBLEM

36. m = 3

Sin = m = sin(IS)= 3(620X10-9) = 15°

d X = 620nm d = 7.18648 x 10-6 m/lines

I = 139150 lines/m - 100

= 1391.50 slits/cm

* Spectroscopy: the process of identifinq atoms by

seeing what frequencies they emit or absorb. - A substance will emit the same frequencies

that it will absorb.

* Thin Film Interference: (Figs. 29 330)

- thin films -> soap bubbles, gas om water,

SANDRA anti-reflective coatings, ect. - this is interference between the initially

reflected light and the internally reflected

light.(Fig. 24-30) the interference occurs when the thickness of the film is on the order of note: the importance of the index of refraction for reflecting in-phase vs, out-of-phase waves, (Fig. 24-32) non-reflective coatings are such that the thickness of the coating and the index of refraction, "A", of the coating are selected to maximize destructive interference of the reflected light.

SOS

IT

CHAPTER 24

CHAPTER 243

WEEK 9

* POLARIZATION

- Unpolarized light => (transverse light that is vibrating

in all possible planes.

Study Soup

- Polarized light >> light that is vibrating in only one

plane.

- Linear Polarizers: this is a transparent material

(usually plastic) that is made up of many parallel dark lines. There are so many dark lines that it looks like tinted material.

* When light passes through a polarizer, only the

light oriented parallel to the polarizer makes it through. (Fig. 24-42)

* REFLECTED LIGHT is atleast mostly polarized oriented

in the direction of the surface that it reflected off of

- note horizontally polarized light is called "glare",

our sunglasses have vertical polarizers to block glare.

* Examples of polarized light comes from:

- LCD TVS, computer screens, calculator screens. (somewhat) cell phones, some gas pumps.

* MULTIPLE POLARIZERS

90° 8=40° So°

-30° 80°

+60* 20°

SO

= ut

for **

11 = Ż I.; each additional polarizer will cut

the intensity by:

O = example 1-2 I.- In-icos261 = 90-50 = 40°

* HOMEWORK EXAMPLE

1) Unpolarized light with an intensity of 16.2 W/m2

passes through 3 polarizers. First is oriented at 350 second at 76, and third at 52° Find the inse intensity of the light that makes it through.

12 = Io = {(16.2) = 8.

leta para la

0-2 = 76-35 - 41° → Iz = 8.1 cos2 (41) = 4.61

2-3 = \$ 76-52 = 24° → 13 = 4.61 cos (24) = 3.85 W/m2

CHAPTER 273

CHAPTER 24

WEEK 9

BREWSTERS OR POLARIZATION ANGLE (OP)

- This is the incident angle that will result in reflected

light that is 100% polarized. (Fig. 24.47) – This occurs when the incident arste reflected and refracted light is perpendicular to each other

Op+ i = 90° Crecall the cosine of one angle will equal the size

of a complementary angle)

Stud

tan Op = nr

* Example: Find the Brewster's angle for an air to water

interface (the light is in the air). (Fig. 24-48) - nw = no = 1.33

nairani = 1 tanop= ns = 1.33

tan-(1.33)= Op = 530

* 3-0 MOVIESWHY IS THE SKY BLUE?:

- Diffraction (best answer) - blue light has wavelength that is shorter than air molecules. The blue from the sun gets scattered in Our atmosphere.

* CAMERAS: note: the focal length is fixed constant)

because the lens is hard. You can change di (the distance from lens to film).

Talui Ent do di

increases

CHAPTER 25

WEEK 9

* CAMERAS: (see Fig. 25-1)

- Since the lens is hard, f is constant - di is adjustable (distance from lens to film) - if do decrease, di must increase and vice versa.

- The "speed" of "f-number of a camera

Fumber

- E D

focal length itis Opening

Studs

- For action pics or for low-lighting pics, you want

a small foumber / speed.

HUMAN EYES: (see Fig. 25-9)

- the pupils is similar to the icis opening of camera - most of the bending of light occurs at the air

to cornea interference.

nair=1, n cornea R 1.376, niens 21.4, humors = 1.337

-

SOU

- Duc lens is convex - entire cornea to back of lens is a convex system.

this means the images formed on the retina are

inverted - note: "F" for our lens is adjustable; our ciliary muscles

can contract down on the lens to make the lense "Chubby" (small "C"), or they can retract to

make the lense "Skinny" Clarge "f") (see Fig. 25-10)

TEE * HUMAN EYES:

- di is the distance from the lens to the

retina and it is constant.

- if do decreases, the f must also decrease

-near-sighted (myopia): you cam see clearly

near objects. Cobjests close to you)

images are forming too soon (inside of eye, before retina, near the lens), you

• You need a diverging lens (concave) to push the image back to the retina (see Fig. 25-11 B)

Far-sighted (hyperopia): you can see fac objects clearly

• images are forming too late

- behind the eye, far from the lens - you need a converging lens (convex) to bring

in the image to your retina. (see Fig. 25-11 D)

Astigmatism: an out-of-round eye.

[CHAPTER 253

CHAPTER 25

WEEK 9

* Near Point: closest distance from your eyes

that you can focus on an object

Far Point: the fasthest distance from your eyes that you can focus on an object.

* Vision Correction:

di will be on the same side es of the glasses or contacts as the object; this means di is negative and it's a virtual image. (true for both neac/fac-sighted)

Stud

• Power of Lenses :

Pat

Cunits : 1 = Diopters "D")

Lape this will be the prescription

K u must use meters!

near-sighted: di = -(Far point-dens)

distance from eyes to glasses do oo

SUV SOU

far - sighted:

dis - near point - duens)

do = where you would like to read

you will be told this #) (where you want to hold object-dlens)

VSP

* CLASS EXAMPLE: Susie can't see clearly when

objects are further than 18cm from her eyes; however she can see clearly as close as llam from her eyes

A) Prescribe glasses that will be 2cm from her eyes.

Crear-sighted) di = -(fac point -diens) = -(0.18-0.02) di = -0.16 .P 1/ 1 do = ook do di

P = -6.25 D

bye i bra

-0.16

8) Prescribe contacts for Susie

diens=0 d; = -0.18 P= I= 1

di -0.18

= -5.55

c) where will Susie's new"near-point" be when

she is wearing her glasses? do = ?

P: -6.25 D di = -(0.1 -0.02) = -0.09 n. point = 11 cm

I V : -6.25 - 1

do 20.09

-0.09 do = 20.57 cm

Study SOU

new "near point" = 22.57 cm

Studio

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