Ch 17 Review Questions - Reflection and Mirrors

B09: I can apply the law of reflection.

1. Draw a picture illustrating the law of reflection, labeling relevant angles. Also, label theincident ray and reflected ray. ~

. . \Mi~/-Ir~ Ite~' I17.1: I can apply the law of reflection to a flat mirror. \ 4(

17.12: I can distinguish between diffuse and specular reflection.

2. What is an example of a surface that has diffuse reflection? Specular? You may want todraw diagram for yourself.

~~~ ~~\~'(t ", !(\'-'11..J - ~l

17.2: I can distingue~ convex and concave mirrors~

3. Which mirror do you think IS often called a "dlvergi~ mirror", the convex or the concave?

,Why? b\'ni.'d";~: (M¥eX. rHA-LL/!'l.- LICl.Hr /J.;+,.,!-~. t::llv'~tL(.c! Pt20M THc Po'14-1. ~6IAJr.- C6"~U.I\ 'N!ll CO•••.'lI,lfe ~~P.~"LL.t!L.LT tAl/! Co;..o/~(d OJ{ P«.A< {Jr.

4. T or F : All incoming rays parallel to the principal axis for a concave mirror get reflected and

then pass through the focal point. Tit-UC .

17.3: I can identify which type of mirror corresponds to a negative or positive focal length.

5a. Explain why you could say that a convex mirror has a "virtual" focal point. This is one wayof interpreting the negative sign of its focal length. rOGAL. .j)(l/IJ r 01\ q[)fri.t SIIJ C t

C" E)SIO~oF Mlt~ot1.. S~('SJtl ~ A-5 l//l1.'TUJ'f(.. 11t1~('t'J(f) Bb. What is another way of remembering/explaining why a convex mirror has a negative focal~~'" length? Think about a number line ... (lj d It\. fltON r tJF MIAiZ.cR (L;('ffi ~/OC)- / MJ::> 0 IS tH /l1J~ W1.,l#l..O/t. (tJ tt.t.,.f oSI ~~ JtL17.4: / can identify whether an image for a given mirror IS considered to have a positive ornegative image distance.

6. What does a negative image distance imply for a mirror? Conversely, what does a positiveimage distance imply? di I. 0 f1.ICt-J ~1~ I~A~ C U o,{' tJA£/<. uiJC'~1'M\~w~ - IT \l; VIR..'l'\A.4-L-. d~>0 th./!.••.. ,t I) a r-t,.a( Ik-vt.W "'1

\1 \, \ l.. ' • T'4.1'\r !,~~ 6 f ,..••lit Q..o !t-17.5: I can ~entify when an object has a positive or negative magnification for a given mirror.

7. What does a negative magnification imply for a mirror? Conversely, what does a positivemagnification imply? Be careful not to make assumptions and to consider all cases. Look atyour notes or draw diagrams if it helps you. M<. () ~ I tll\.ILJ~ 1''''''ulIXi''W.

1'\'0 i1i(N \•.•...~c..~U!<..i.

17.1: I can apply the law of reflection to a flat mirror.

Ch 17 Review Questions - Reflection and Mirrors

B09: I can apply the law of reflection.

1. Draw a picture illustrating the law of reflection, labeling relevant angles. Also, label theincident ray and reflected ray. e. (14""'" /

"$.'Y17.12: I can distinguish between diffuse and specular reflection.

2. What is an example of a surface that has diffuse reflection? Specular? You may want to

draw diagram for yourself. ~ p."t:: t.../, ~r ,(. r &"..,J . L • J .V'oc.l I ~lr"or. $1"U4Iltt.U !~/

I VG OloLv SIlver I

17.2: I can distinguish between convex and concave mirrors.

3. Which mirror do you think is often called a "diverging mirror", th~r the concave?Why?

4. T or F : All incoming rays parallel to the principal axis for a concave mirror get reflected andthen pass through the focal point.

17.3: I can identify which type of mirror corresponds to a negative or positive focal length.

5a. Explain why you could say that a convex mirror has aof interpreting the negative sign of its focal length.

5b. What is another way of remembering/explaining whylength? Think about a number line ...

ual" focal point. This is one way

-.;..y" fcec-I p 1-.co vex mirror has a negative focal

17.4: I can identify whether an image for a given mirror is considered to have a positive ornegative image distance.

6. What does a negative image distance imply for a mirror? Conversely, what does a positiveimage distance imply? ~ ••0

-:A'~17.5: I can identify when an object has a positive or negative magnificatio

7. What does a negative magnification imply for a mirror? Conversely, what does a positivemagnification imply? .Be careful. not to make assum~tions and to consider all cases. Look at

your notes or draw diagrams If It helps you. l'\ It ~ ~:I(. 0 bjec.r:J. 1''l.IJdte4.,

17.6: I can identify when an object has an absolute value of magnification less than unity orgreater than unity for a mirror. (Note: "unity" is the fancy science/math word for the number 1)

8. If an image has a magnification of -4.2, what does that mean? How would that change if it

were +4.2? \ I'\~tull ~tv" LPfl) ba.h S r-e.a-l)lJ.~r~jkt\~e.v lpr"Dhdla~ II/rl-~l)

9. If an image has a magnification of -0.7, what does that mean~ ~ow would that change if it

were +0.77 ~~ev- ..f :f'.....,~ftr.J.~~b..-~l~~!JS/ll\aller- ~ lJ.f't"\~\...t- [pill bala S vt',.~

17.7: I can draw ray diagrams for both convex and concave mirrors.

10. Can you jot down, in your own words, 2-3 steps explaining how to do a ray diagram forconcave mirrors? Convex? Don't look at the list of steps given on the worksheet. The only

/0\ (> kthiog you may use is an actual ray diagram to jog your memory.o 1" Q 'SP6 j :::; ~ ~_ I "I £P l?f-,tr:tJ '? """Q 4'( FC~ 9 r P'I'@ "DQ..A!J I"~~- ,c.5iJdr paoallel ,0 PNGd't; ;r~-"1P'lfJ

to cc.••..fv 1,;"" J I~ 'ftlh' +l..>"e1 k (bud 1r. 5!<!: ,q.-rrf9-CII~.17.8: I can label all relevant variab/~ on a ray diagram.

17.9: I can calculate the object distance, image distance or focal length of a mirror when givensufficient information in a problem.

17.10: I can calculate the object height or image height when given sufficient information in aproblem.

17.11: I can calculate the magnification of a mirror when given sufficient information in aproblem.

I have a 65 mm focal lengt~ONVEX mirror. I place an upright meter-stick 25 mm from

the mirror. t :::-bS"'""... de.-25'1tIN! ii. .::? ..L, 1 111a. Draw a sketch of the situation using a straight-edge. rf P cI.. + d"", r (" f)

11b. Find the image distance. Comment on its sign. " t{1- 18,.... ..

11c. Find the magnification. Comment on its magnitude and sign. ,IM. •..t 0.7 ( L \ - - " -

11d. Find the image height. -e;l~ -Cl~ f. d, e;(:~_ "l " 6..J-f O.7",~ ~\.= d~' 25•••" .J- __I _-L

.. l--. \.0 ff~~.jJ -tS".- ~..,. dL2) The use of wave fronts and rays to describe optical phenomena s c{J '. _ /8?

A wave 0 tiCS. J! ~ ~geometrical optiCS.

C) Isperslve op ICS.D) quantum optics.

Answer: BDiff: 1

Concave (converging) Mirrors

1. Pick spot on object farthest from principal axis.2. Extend the line of the mirror. (Use only the straight edge of the mirror. Don't use

the curved surface to solve problems.)3. Draw first light ray from spot on object parallel to principal axis. The light ray

bounces off mirror directly toward focal point. (Note: for concave mirrors, thefocal point is on the light side of the mirror.) Extend dotted line from the point itbounces directly away from the beam that bounced.

4. Draw second light ray from spot on object directly toward focal point. The lightray will bounce off the mirror parallel to principal axis. Extend dotted line fromthe point it bounces directly away from the beam that bounced. Note: this lightray may not be able to be drawn on all problems.

5. Draw third light ray from spot on object directly to the center of the mirror alongthe principal axis. The incident light ray will bounce off at the same angle to theprincipal axis as it's incident angle. Extend dotted line from the point it bouncesdirectly away from the beam that bounced.

6. Where the three light rays appear to meet or meet is where the image of the spoton the object is. Draw in the object with the bottom of the object remaining onthe principal axis. Note: the image could be real or virtual on the light or darkside.

7. Measure di, hi and determine real or virtual and inverted or erect.

Steps for graphical method of curved mirror problems

Convex (diverging) Mirrors

1. Pick spot on object farthest from principal axis.2. Extend the line of the mirror. (Use only the straight edge of the mirror. Don't use

the curved surface to solve problems.)3. Draw first light ray from spot on object parallel to principal axis. The light ray

bounces off mirror directly away from focal point. (Note: for convex mirrors, thefocal point is on the dark side of the mirror.) Extend dolled line from the point itbounces directly away from the beam that bounced.

4. Draw second light ray from spot on object directly toward focal point. The lightray will bounce off the mirror parallel to principal axis. Extend dolled line fromthe point it bounces directly away from the beam that bounced.

5. Draw third light ray from spot on object directly to the center of the mirror alongthe principal axis. The incident light ray will bounce off at the same angle to theprincipal axis as it's incident angle. Extend dolled line from the point it bouncesdirectly away from the beam that bounced.

6. Where the three light rays appear to meet, on the dark side is where the image ofthe spot on the object is. Draw in the object with the bottom of the objectremaining on the principal axis.

7. Measure di, hi and determine real or virtual and inverted or erect.

1) A laser beam strikes a plane reflecting surface with an angle of incidence of 3r. What is the anglebetween the incident ray and the reflected ray?

e. :G.I r

G~=37.6~= er ,.3r

e~r (Jr E 37"f37@10"Cl'" JL.~"Z. •

tnll'\ M,~l

3) The angle of incidence can vary between zero andA) 1 radian.

rr/2 radiansC IT ra ians.0) 2lT radians.E) 3lT/2 radians.

Answer: 74.0°Diff:2

Answer: BDiff:1

4) Law of reflection is which of the following?

~B) (AZ/AI) (sinOl/sinUZ) = 1

C) ,.,(d/n)

D) A/Am

E) arc sin(nz/nl)

Answer: ADiff: 1

C) specular.

Answer: ADiff: 1

6) Refle 'rror is calledA) specular reflection.

C) irregular reflection.0) internal reflection.

Answer: ADiff: 1

Answer: ADiff:1

2) The IMAGE of a plane mirror (of a real object) has tee folio ing chara~~ristics:5,.,t\LO ~

A) virtual, inverted, and magnification> 1 X' -"1' I:;~ua ,erect and ma nl Ica 10 - ' '. ,1',

real, erect, and magnification = 1 -),D) real, inverted, and magnification < 1

Answer: BDiff: 2

Ib Co,., 'j3) David stands 2.5 meters in front of a plane mirror. (J t.s•../ 2.••• ~.:

( ) H f f D'd' 0 'd" . th '? ' I-G-=' {G---?;a ow ar rom aVI IS aVI s Image In e mirror. / \ /.(b) If David moves away from the mirror at 1.5 ml s, how fast are David and his image moving

apart from each other?(c) If David is 180. cm tall, how tall is his image in the mirror? {.,r; I.r•../

~'>i -? 0Answer: (a) 5.0 m (

(b) 3.0 m/s l.r .••.1.!-c I.r",&) = 5,0_&(c) 180. cm

Diff:3

5) Suppose a lighted candle is placed a short distance from a plane mirror, as shown here.Where will the image of the flame be located?

A) at A

~at) at M (at the mirror)

M s.Answer: CDiff:2

13) You may have seen ambulances on the street with the Jetters of the word AMBULANCE writtenon the front of them, in such a way as to appear correctly when viewed in your car's rear-viewmirror.

a) 'V~snTI1N:)E

c) ECNALUBMA

b) AMBUJAvD3 How do the letters appear when you look directly atthe ambulance?

A) figure aB) figure bC) figure c~Preb09ure e

Answer: EDiff: 2

Answer: ADiff: 2

d.~= i•..,.4J~/..dtJ, h1t1£ ~

do = 0 bjed e/6~ftu"e.

1) If you stand in front of a Gonvex mirror, at the same distance from it as its focal length,you WI see your I a WI appear smaller. c;:{ Ii

ur Image ecau .. ~ ~ foW; erC) you will see your image and you will appear larger. o./lI.J<1.jS up •..~hD) you will see your image at your same height. a I~ u I tw..IE) you won't see your image because it's focused at a different distance. ~l~ ,,r I, /

.c.. ~~ wlJe.; ~el<fol-U6.aliIJtitj ~ ~Xl.c~;.

6) The magnification M = -d;l do is the ratio of image to objectr size.

B) distance.s ances.

D) heights.

Answer: BDiff: 1

Answer: (a) real(b) 17. cm(c) inverted(d) 2.1 cmDiff: 3

Answer~Diff2 V12) Which of the following is an accurate statement? l

A) A mirror always forms a virtual image. tI. et- 0. ~ ~B) A mirror always forms a real image. l'-<)t A \~ Ie) A mirror always forms an image larger than the object. 1\..Ct- a.lW~..sD) A m' n image smaller than the object. t\.I t- ",LlIJ"j.-S

None of the other choices are r .

7) A 3.0 cm tall statue is 24. cm in front of a concave mirror. The mirror radius of curvature is 20. cm.(a) Is the image real or virtual? 1) r 2."'c (I r 'UJ_(b) How far is the image from the mirrOr?~. ~ '" T L Z:" ""£'(c) Is the image upright or inverted? D k : 3.0... p • 10(d) How high is the image? /) ~"'"

.J....I cL ~2 V..... _IrIA :. 9V-r-

o: I _' v fI'I.:: ~ " 2 - /7.!(Jo,

1''' 11\. - r L Ja Z 1'.",I.U \ t .•d~ d. Lk~-;nil. ..L _.1 _ .L '= -0,7 (

{().7'j...~.6t,...1 P do - d. ''".L>eltui_--..... .1 \ •

(••2.k••..) IQ..-e~ ~di k.f'\ M~10) Describe a mirror which takes an object at a distance of 47.Q;BiJ,icf1lorms a real~mage at 23~

Answer: concave mirror with focal length 15.4. cm (radius 31. cm) ~~ &6 :l/7e.,..Diff: 2 d~:::Z 5<:",

l...J.tl.l-r1t d~ do C( kJ;. Zi:...

[f ~1~711) A negative ma nific .

e image is inverted, and the mirror is concavee ,mage I , mirror IS convex.

C) the image is inverted, and the mirror may be concave or convex.D) the image is upright, and the mirror may be concave or convex.E) the image is upright, and the mirror is convex.

lC 6n.l~OY\L toJI.;,. 'f'"r} (' - fu1'\

L 6 l\.(£V <-

Answer: EDiff:2

13) Two parallel rays (also parallel to the principal axis) reflect from a concave mirror. They intersectat

A) the center of curvature.~~e focal pOI~

C) point beliln the mirror.D) infinity.

Answer: BDiff: 2

15) Sometimes when you look into a curved mirror you see a magnified image (a great big you!) andsometimes you see a diminished image (a little you). If you look at the bottom (convex) side of a shinyspoon, what will you see?

A) You will either see a little you or a great big you, depending on how near you are to thespoon. ( ~ • I ~

B) Yo' . u u side down. d:I/'!.Ytt'" ~ '-'-f''JlllrYou will see a little ight side u 6r;t« J'j "..I~"I ~ e...-

D 0 won t see an image rself because no image will be formed. a./~S V/j2.1U.II}J...E) You will see a little you, but whether you are right side up or upside down dep~nds on how

near you are to the spoon. Aw.4.l(..1 tllPeIV'S ~~~.Answer: COiff: 2

19) An object is placed 6 cm from a concave mirror of radius 4 cm. Graphically determine:(a) the image position.(b) if the image is larger, smaller, or the same size as the object. ('::: l.( eWl

(c) if the image is real or virtual. (l An.: ~ "i"" =2av.,1\\: ~ ~ -~ TTl r;z.t..., Ofo~ ~,.... r- c.. ,-

Answer: (a) (shown) d. i:f.,,,,. l2J d~:-: IJ':> - - J ::Jr ...((._ \ _ L _ 2~•• / ~ de'(b) smaller ~ ~ •...•....= ~ r IX-'

(c) real \ f de tf. ~':1Oiff:3 l'I.l/'V~tJ ,j". _ I I txL c. ••••

'- f a;:;r --21) The rear-view mirrors on the passenger side of many new cars have a 'warn1ng written on them:"OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR." This implies that the mirror must be

A) concave.B.lplane.(Cf CQDvex. )D) transparent.

Answer: COiff: 1

Try the math.)

A) you will see your image and you will appear smaller.B) you will see your image and you will appear larger.C) you won't see your image because there is none.

, ur ima e because it's focused at a different/distance.E) you will see your ima r same hel -t \f\.1Jt[ta.

23) If you stand in front of a concave mirror, exactly at its center of curvature,

tAnswer: E (you are twice the focal length away.

Oiff: t'i r.\(d) l = CJ,\j:aD)\ I) ~ ' n

~ ~ :0 ~y',iv)&~::: 0 --Lio

24) If you stand in fr~nt of ~irror, at the same distance from it as its ra?ius of curvature,A) you won't see yo~b~cause there is none. tJ. t' ~B)you will see your image and ou will a ear lar er. I

see our Image and ou will appear smaller II ,(you WI see yo ge at your same elg 1. ~~ ~~/j e."

E) you won't see your image because it's focused at a different distance. (I {~ ltfl'lj ~{-

Answer: C \U)r~•••l\ "'t"".s./INl.llv a{~c lJlll'ttt~LOiff: 2 ~, -..J

r::: 2D(JIII.

'-'0= Lj.ll """.I . -.,CA l, •••.•

I . ;71'\ ~ •

(a) where is the image formed?(b) how tall is it?

Answer: (a) 60. cm behind the mirror(b) 16. cm tall

Oiff: 3

25) An object 2.0 cm tall is placed 24. cm in front of a convex mirror whose focal length is 30. cm.(a) Where is the image formed? \.. ~ Z.D... til 6 ••••"2 '{ "'''' fl:; ~30 ""(b) How tall is it? 0 c. t,~ ::1. +-J. .l. - .1. ~ .1.

Answer: (a) 14. cm behind the mirror ft. .f cPo di.(b) 1.2 cm tall _,(~ -fI3.~) ..L__ 1. :"1

h- 'r. M.= -d "(/ -jo"... 21ft... de.Oi!!: 3 ~ :> IV\. 0 '2. , (.M ~ ----;-::;-::;-:Jl

h. "t~.o~~~~ I :: 4- ().s{, /, ~~ -/S.5c=;J.26) An object is placed 15. cm from a~ mirror OTfocal length .J~. Ci I I. If the object is 4.0 cmtall,

Chapter 18 Focused Review - Refraction and Lenses

Reference Information

Medium Index of refraction Medium Index of refractionVacuum 1.00000 Crown alass 1.52Air 1.0003 Quartz 1.54

Water 1.33 Flint alass 1.61Ethanol 1.36 Diamond 2.42

ROE Objectives

808. I can identify and describe refraction.

What causes refraction? When does is occur?U~W-\x.d~~J."e to ~~ S~ J ~IIA 6","e... WtdL~

~ Ct-~{'

OPRF Physics Custom Objectives ~

1. I can locate angle of incidence and angle of refraction on a Snell's law ~gram.

What is a "normal line" in the context of Snell's law?

~e.{"p~~W lo +k. &U.rfa.te

2. I can define index of refraction mathematically and explain its meaning in my own words.

Given the speed of light in cubicblingonia is 2.5 x 108 mIs, the index of refraction

in this substance is . y\;; ..f..:: 3'.00 At"" 1$ t:@'"V 7.S-XI ,,4 x6 ::. I.L

3. I can predict what will happen when a ray of light traveling through a medium approache theboundary to another medium with a different index of refraction.

Explain how a mirage occurs, making mention of refractive index, temperature,and light rays. l.,,~1"i.

r e.-~~l-tIOY) ,

4. I can define Snell's law and use it to analyze different scenarios concerning refraction.

What is Snell's law used for? Be specific in your description and use accuratevocabulary.

Chapter 18 Focused Review - Refraction and Lenses revised 04/18/11

Reference Information

Medium Index of refraction Medium Index of refractionVacuum 1.00000 Crown alass 1.52Air 1.0003 Quartz 1.54

Water 1.33 Flint alass 1.61Ethanol 1.36 Diamond 2.42

ROE Objectives

808. I can identify and describe refraction.

What causes refraction? When does is occur?

Cb!l~"& Of Sf' l!6 D or U<.Hr Fil.<lil'\. 01\. , ~ u.a.5.r"fA/l.C rajJ.l\Ol1~~R.'lf'l;t!.:D Tlie 1\""<"1.£ ()F 11"£' Ol!I- (.C

OPRF Physics Custom Objectives

1. I can locate angle of incidence and angle of refraction on a Snell's law diagram.

What is a "normal line" in the context of Snell's law?

A, Will. ~[~j)O.1tllt.Lll.A,l.. '1\) l?/~ Su.rt FACe or 7HC. IN n:::Il F/'K!

2. I can define index of refraction mathematically and explain its meaning in my own words.

Given the speed of light in cubicblingonia is 2.5 x 108 mIs, the index of refractionin this substance is ~ /11 = ~ 3,00'1(0 t~ 1/-;-;--)

(T z. '5"0 )CIO' "'4 . ~3. I can predict what will happen when a ray of light traveling through a medium approaches the

boundary to another medium with a different index of refraction.

~\('L Il~FR..A-LT.!.Lt 4-HiLIIIJ L.I!,L A-I fL ~ Su••..e,t. StJIFlf£)

Explain how a mirage occurs, making mention of refractive index, temperature,and light r

~or4. I can define Snell's law and use it to analyze different scenarios concerning refraction.

What is Snell's law used for? Be specific in your description and use accurate

vocabulary. I, I~ wtO ro f"tNJ) 'rHt! A'IJ~L.C dF R..c.F/2AU7011J ,C\J{.IJ Tl'tt 1'\ "'<" uc Or IN c.we /oJ {r! (feol'< 1ffCNGt."'IJ-£) AN f)

~{ \f\!l(JI or IH ..f~c.n4'" 4F ~II! tw~ .\J1l srAr'J(CJ .

5. I can describe total internal reflection in my own words and calculate "critical angle".

How does a fiber optic cable work?

k ~s. TD/l\t..- INn:ItAltl-L R..Cf~Ll(..no"" 'V

llG.ltr ti\~ VlITHIN iW( fL.!\L IBLt" C-A&6

6. I can define dis ZSion ,recognize examples of dispersion, and explain its connection with theconcept of refraction.

Why does dispersion happen? Explain why different colors of light refract tovarying degrees (no pun intended).

h 'itf\I'Pt.tJs t:,\!.C~C l\{~ IN \)~)( 6F tt'F",e./kTlGI\IS !>\ ri'H.E.lJr foe- 1::llFt=!:etNT W>\V~Ll!N"rl1~ OF LICHT. AtJ[).-I1-tt <;1l)E'~or ~I! 1l~\Sfl\ 1f<..f.N'r 01.tAu..&I.. ..

7. I can distinguish between the shape & characteristics of a concave lens versus those of aconvex lens.

What kind of images can concave lenses produce? Convex?" j)11"'e.~,,,,~r...,\\/c!i.lil •.••~

ON1..'1 IIllLru.;H.. I ~i!c.j Ma .sM~~- - - ---T/t'NNl!iL ''I. IAlAe 1..0:.

Co'll.. vl!t2 c, ''''(, (f1tIC.~t!li!.I'" ••••., ~O L~)f'\A~ ll.l" v 11;[t't<.A.L. 1\ tJ n c/1.«:r fI: tv C I.. Ii il.' C!fl- .Mill-/. ~'e: 12-£A-L, INV(~O fiNO S/lIA-lJi!'.t, Wl-otl6"A. Oa .stPltC.s(ze-.

What kind of lens would you use for a magnifying glass and why? Use previousray diagrams if you're stuck.

fV\It G. N I r'l,1'<G c. LI\-~ : C ()I'..IJ (;tt f.t tN C{ L.6\J ~ •

\

t>r 1/Vl...", IN 't8. I can interpret/comment on the numerical value of the focal length for a concave lens and for

a convex lens.UrJ... V"WL I; IN"

Which lens has a positive focal length? Negative?

eo.,..v t/L I.j ( "4. - ~O~(n I(/C

DlV-tlt It , '" II - 1\1C<; Itill/t!9. I can interpret/comment on the numerical value of the image distance for a concave lens and

for a convex lens.

When could you get a negative image location? What does the negative mean?

di <0 l>'k.~ ;1- 1~,>\. .s a->"l~SIde' ~J ~ ~ jeJ qJ VI-eru4L.

QM.U(.,,-~.t :." tJ"-. J.4.,"l.e.. s.,'.i••.Q.l.Gb j...J.

10.1 can interpret/comment on the numerical value of the magnification for a concave lens and fora convex lens.

What does a negative magnification imply? Be precise in the wording of your

answer. VV\ (- 0 l).Ih e."- .\ ~ ~ e... i') \ 'i\. o,N.,('4..cJ;,f I

\t fi\e14~ ~ H".A~e...~e.:..J~t

11.1 can use the lens equation to make predictions about image position and other relevantvariables for a given optics scenario.

or~o~k: _cL

r\\.;: C =-;£1. L_J'-(ti,..., I We.""' - -t•..l-_L _1_.3:-I z()c~ I"'t"" - &lc. - I~ .•.

"Pr".:k s"l..... -?f.?~i~"'-!7,.

1 .L + L~ J: Jo

.L_1 • J '=-f J, J~

An object that is 30 em tall is held 120 em away from a convex lens of focallength of 40 em. Does the image form on the same side as the object or on theopposite side? At what distance?

k~30 c.Ao\ Jo ~ lzp """'-

()be either erect or inverted

e<\The image that your eye receives is

a. Erect b. inverted c. cod. cannot determine

12.1 can describe diagram how lenses relate to human vision and their applications for correctioncommon vision problems.

Light entering the eye focuses on a layer of light-sensitive tissue at the back ofthe eye called the \<..~'I IN l'r .

13.1 can draw a ray for convex and for concave lenses.

Complete the ray diagram for the lens below showing the image location, sizeand orientation.

- -- -~."Right-side-up" 6erted:J ~

\

Complete th raand orientatio .

22.1 Wave Fronts and Rays

2) The use of wave fronts and rays to describe optical phenomena is calledA) wave optics.B) geometrical optics.C) dispersive optics.0) quantum optics.

Answer: BDiff:/

22.3 Refraction

Y\. Sl'(\ 9, .= ,,~ ~/t6~V\," I.1\ 5 1'1\e,

Y\l.

~i;::{toi.a}

1) A ray of light, which is traveling in a vacuum, is incident on a glass plate (n = ng). For increasingangles of incidence, the angle of refraction

A) increases, approaching the limiting value of 90°.B eGreaseS~RQrOiffihing the limitin value of zero de rees.C) inc ases, approac il g!lie Imiting value 0 sin" (1/ng) degrees.

increases, approaclilng he1lmltlng value of sin '(17f19tde-g s.

Answer: CDif!' 2

Chapter 22 Ref/ection and Refraction of Light

@VhiCh of the following is equivalent to Snell's Law? (v is light velocity)- . C.

A) VI / V2; sin(81) sin(82) r\ \ ~B) vI t.n(OI) ~ V2 t.n(82) - I -

f\ "2 (".C) VJ I V2; sin(02) I sin(81)

D) VI I V2= sin(81) I sin(02) ~.(..

E) nl sin(82) ; n2 sin(81) ~ Cc..;,S •.•C, ~ o.I.r vt.o r QUI ~

Answer: 0Diff:2

Answer: (a) 6.38 x 1014 Hz(b) 320. nm(c) 41.1°

Diff:3

3) A light beam having a wavelength of 470. nm in air is directed into glycerine (n = 1.47).(a) What is the frequency of the light in the glycerine? r .£ 3 e(b) What is its wavelength in the glycerine? ~ f _.CXJf,(O 1J(c) If the incident angle is 75.0°,what is the refracted angle? A ~ V70'ItO"I",

l\,:' l.~dG~ ,

1"-, $1"-6, = Ih 5''16 z. <;:;; ~ c.. '3 r 'II0 '~"ti\,SiVlCl, ~ Si",ti.... A~-r-=

~z c tt'"' -I ~I\ 1'\ =-V.:> I/] ~ S ,iI {)/ I -= I.,'

h ~ _I.h___ \.J.- s;.E.9l,0) V\.

4) As light refracts going from one medium to another, which of the following remains constant?A) wavelengthB) refractive indexC) wave velocity0) frequency - ~"~u.~

~swer:o)iff: 2

ow long does it take a light beam to cross a 6. m wide room? If the air were replaced with atransparent medium of index n, how muchfnger would it take?NCX I \f== =c .b _ cd _ , '" .P~() (,,[)OtA l" - c.. - '3.()(1'(.{Of-r.:: 2.. ,OO"'/{ IJ"S

Answer: 2 x 10.8 s; n times longer _ C. '"~ l --.,fLO,ff:3 \1\ - I' - , ,r_ - .I- _ _ _ 11..\ =- ,:. ,,- -t=- .. v- r"\ ~- IT - S:t. - l\lI..J ~~

iD"'hen looking into a pond or lake of clear water, the apparent depth is wh~t"l)aCtiOn of the actuall&~ih?A) 1/4

Q. B) 1/3~C) 1/2Vj 0) 9/10

E) 3/4

Not>£) I~bUII\.:

Answer:-EOiff:3

~ Snell's law can be written as: sin(OI) / sin(1l2) = _-...:~ A) ,,~ / "I B) /'1/ /'2 C) h / f2\[j \'0.\: >0 ~"cJ~' f\, ,:J VI e, =- ~ <- ~; "'- t:\.

Answer: B , (j C-Oiff: 2 (\.. • Sjf\ !

h, $(/lO-Z9) If a transparent material has an index of refraction of 1.67, what is the speed of light in thematerial? C.v= 7 S\:=-;-,....Answer: 0.599c = 1.80 x 108 m/ s vOiff: 2

() ~Red light with a wavelength of 650. nm travels from air into a liquid with an index of 1.33. What is~ Ifh:frequency and wavelength in the liquid? \~IJ'..Ot )\ -::(,)'0,.. M.. 1'\ I" /. 0(;" S VI -" l •.\!J Answer: 4.61 x 1014Hz and 489. nm •. '..J 3

Oiff: 3

T~~L£ 6F INj)c::',( (jF ~tf{lA-L1"lD"I.

1\ "l.~".....~..J,~ 3 rc~.J(!>t

11) My flashlight beam makes an angle of 60. degrees with the surface of the water before it entersthe water. In the water what angle does the beam make with the surface? It'l - ~ 0 '

$0' 0, - ..J(;)l.~?Y\,

Answer: EDiff:/

t::, e: 't2. \/'3. - '{Z . ~()Y'(: O. '270 f13) Which of the following materials has the slowest speed of light?

A) waterB) oilC) air0) flint glassE) diamond - S tl..

Answer: ADiff: 3

A) 0°B) 30°C) 60°0) 22°E) 68°

Ans~er: E \ T 'f.'\\l.~1 {'Co\{cu,t -\-ows-rJ ~ ~~t -~ol""4 ~"M 4.~~e..i{a.,'rDiff: 2 - -JrI" \0 <; \ tI u-'<>f '-.J Q,\if .~~ 1ray of light consisting of blue light (wavelength 480 nm) and red light (wavelength 670 nm) is~t on a thick piece of glass at 80°. What is the angular separation between the refracted redand refracted blue beams whiie they are in the glass? (The respective indices of refraction for theblue light and the red light are 1.4636and 1.4561.) . L\

Q e _ I\l-Sl".8\ =: f\ •.S('l.C''L,, A) 0.27r He.\' •~ B) 0.455° .• 1 (1_.OiP3. Sl 1\ ~o~:::: ~L.)o~'~ 5 ll\$, ~ <;,>,61-gl~:~;~:51" ~I.'t~~" J h ,-I (~ ' \_

E) 0.341° $I(\' l ~\I\e,) - 6t-0 1\•..V'lewlJ

(\.OOCJ~ t 01\ tJ5\1\.••. l~ ~/l.l]oJ):' ,2. '573

-

14) Light of wavelength 550. nm in air is found to travel at 1.96x 108 ml s in a certain liquid.~etermine the index of refraction of the liquid,

~~~etermine the frequency of the light in air. lJ:: l. q b 'it08 >{/v;~ C 'li .I {-f

Answer: (a) 1.53 r\ :: _ -=.:.,GG)<{(} Jt,(

(bj 5.45 x 10'4 Hz U , 'II.v'd "t I. S""3Dlff:3 f \r .

=- -- _ j,oo itl/if S lJ _. fC( 1/A - . SSO.x({).t" C"7J' VlO rtt.15) A beam of light (f = 5 x 10'4 Hz) enters a piece of glass (n = 1.5). What is the ~cy of t elight while it is in the glass?

A) 5 x 10'4 Hz £.,. FLUclt."ol' V ,~~;~.(B)7.5 X 10,4 Hz <.r lI..l~N '\

C) 3.33 X 1014HzO)5x1013HzE) 7.5 x 10'3 Hz

Answer: AOiff: 1-a"-~IND ON ~ oIL 6tr.(afL

parallel light beam containing two wavelengths. 480. nm and 700. nm, strikes a plain piece ofss at an angle of incidence of 60°. The index of refraction of the glass is 1.4830 at 480. nm and

Q.2 .4760 at 700. nm. Det r ine the angle between the two beams in thEtglass. IV I au:,~-0' . ' ° ,'CO I\'SI;IG,.oflL5IV' 4 'I ~'.{IL't,,~Uo51~6()$;JS,7,(z..s-'V'fAnswer. 0.196 ;1 " r. ~ " -I (\ '1/{, I. So'O'ff3 It '.J.,L,,~II\.O -:-5/1\. 01" SlAllO::3 ~I 1\, I I. u'

5'~""l~SIA.e,'Y61 ,{t£.17) An oil layer that is 5.0 cm thick is spread smoothly and evenly over the surface of water on awindless day. What is the angle of refraction in the water for a ray of light that has an angle ofincidence of 45° as it enters the oil from the air above? (The index of refraction for oil is 1.15, and forwater it is 1.33.) El, V\,SiV\.L>,= I\,SIA8l... G,:'-{<;" 1'1,:/.0003

~I /I t1,.<'/,I~-

A) 32.11 V\ siA.~ ' r:.B) 27.2° , ' .: ~("- ua Y13 • 1.33r- .•..C) 35.5° '7 1\•..~1,,6>-:I\~~;,,~D) 25.6° S;~' f~ ""-0\ = e /""\E) 38.6° ~"L~ 'IJ L 5;,,"1 L ,,: SinG':).:" ~

Answer: A Si,,:'(\'I.iJO!> Sr",l{~:)~0~ ."Uti:Sl"~~\'"\..:1. Is S'''C''~) V]

Oiff: 2 =3f3'D,o' fj'-2,-r-018) A light beam composed of red and blue light is incident upon a rectangular glass plate, asshown.

.--/2.i!

The light emerges into the air from point P as two separate beamsA) that are parallel, with the red beam displaced below the blue beam.S) that are parallel, with the blue beam displaced below the red beam.C) that are not parallel, with the blue beam displaced below the red beam.D) that are not parallel, with the red beam displaced below the blue beam.

Answer: SOiff:3

19) A ray of light, which is traveling in air, is incident on a glass plate at a 45° angle. The angle ofrefraction in the glas's

" t(~1,. ~_g~r than 45°. -= ~~~is less than 45") l\

C) is equal to 45°. t\D) is unknown because it all depends on the index of refraction of glass. 61..

A~swer: B eJi!.. (8, Jjc.jOfff: 1 +0t1\ ~r t (.r-j ro

.s IO<>'C/ ~.J~I20) When a ray of light passes obliquely from one medium y; another, which of the followingchanges? (NOrt:: THCU M.lL..5.t BE- "TWo

A) direction of travel ~ lffC~l,jr /1110 ex CJ ofB) speed, direction of travel, but not wavelength p.. (,-fe...I'k.."l-" )C) wave~og -, I u 1\

wavelength, speed, & direction of traveE spee

Answer: D Fl.W 5,TA"'-fS, THe ~i")7l1 LOiff: 2

~ point source of light is positioned 20.0m below the surface of a lake. What is the diameter of the~st circle on the surface of the water through which light can emerge?

,'VAnswer: 45.6mVJ Oiff:2

Answer: DOiff:2

A) n = 1.43B) n=1.53C) n = 1.40D)n=1.48E) n=1.44

22) A beam of light, traveling in air, strikes a plate of transparent material at an angle of incidence of56°. It is observed that the reflected and refracted beams form an angle of 90°. What is the index ofrefraction of this material? 1~G & i. "$,. y\ = 7 .~ So [1\ 19 ~n .911$6 .," ~"\l I, Z

1\,; to{)U~

F

E

glass

23) Shown here are somecan follow in going eitheror from air into glass.

In the drawing you are not told whether the light is going from left to right or from right to left.Which path did the light follow?

A) path CB) path G

~:~~)E) path 0

Answer: 0Diff:2

24) When a beam of light (wavelength = 590 nrn), originally traveling in air, enters a piece of glass(index of refraction 1.50), its frequency

A) increases by a factor of 1.50.B) is reduced to 2/3 its original value.

0) IS unaffected;) ffZ.W u..CV d NOr ~Ff~@.D) increases by a factor of,fiE) increases by a factor of.Vii

Answer: CDiff: 1

25) When a beam of light (wavelength = 590 nrn), originally traveling in air, enters a piece of glass(index of refraction 1.50), its wavelength

. A) increases by a factor of 1.50.B) is reduced to 2/3 its original value.C) is unaffected.D) increases by a factor of. .Vii.E) is reduced by a factor of .. Vii.

Answer: BDiff: 2

26) For all transparent material substances, the index of refraction. less than 1.

B) is greater than 1.

C) is equal t01.D) could be greater than 1 or less than 1; it all depends on optical density.

Answer: SOiff: 1

27) The angle of incidenceA) is always greater than the angle of refraction.S) must equal the angle of refraction.G) is always less thanlhaaogle.oLrefractiD) may be greater than, less than, or equal to the angle of refractio

Answer: 0Oiff 2

28) Light travels faste ta vacuum.roug water.

C) through glass.D) through diamond.

_ 9, >Sz. ,r &ciPf'(JI'II fa!> fey J.slower

8', ~.2. i!jC1l~ /;CNt1

S l~ +0 'Prts}-ere, =- 8z.- lit ~nL

Answer: AOiff: 1

~ light ray strikes a glass plate of thickness 0.80 cm at an angle of incidence of 60°. The index of~ion of the glass is 1.55. Sy how much is the beam displaced from its original line of travel after"it has passed through the glass?

~Answer: 0.42 cm .Oiff3

31) The index of refraction of diamond is 2.42. This means that a given wavelength of light travels

A) 2.42 times faster in air than it does in diamond.B) 2.4 . s faster in diamond than it does in vacuum.2.42 times faster in vacuum than it dO: in diamond.":). Imes a . iemene li:laH-il-d 5 ill air.

F~La:I-J'-'i LGJl1A-iIJSTl-f6 SJtM.c

Answer: COiff: 2 -tI'I.A.L ttl SCi - .Por .3 S lj ~'s~.Its {i1A Ij ,l j 0£{

v.s, L 5 .s l' ~t'lJ~I- '!-G Va (u€- tJ JL -(feve.v..-f)32) When a light wave enters into a medi m of'different optical density

A its seed and frequency change.S its speed and wave ength c ange.C) its requency an ength-eha ge.D) its speed, frequency, and wavelength change.

Answer: BOiff: 2

~i9ht of wavelength 550 nm in air is found to travel at 1.96x 108 ml s in a certain liquid.

SIL-\\> .

Determine(a) the frequency of the light in the liquid.(b) the wavelength of the light in the liquid.

Answer: (a) 5.45 x 1014Hz(b) 359. nmDiff:3

~ex of refraction is which of the following?A) Ri =Rr

B) (i-211-1) (sinRI/sinR2) = I

C) = (d/n)OJ i-11mE) arc s;n(n2/nl)

Answer: DDiff:2

f3S)).pparent depth is which of the following?L2\ A)ej=er

B) (A?11..1) (sine 1 1sineZ) = 1

~~/;Ul"-m -

E) arc sin(nzlnl)

Answer: CDiff: 2

36) Optical density is directly proportional to

A) mass density.

A) O. = 0Answer: CDiff:2

B) 0-2/)1.1) (sin01isin02) = 1

C) == (din) V\~.hu-D)Ai~ ~=fX

Answer: BDiff:2

Answer: BDiff: 1

G[-:37°1\, :: \.OOOjl\'\,..~\.1.3

22.4 Total Internal Reflection and Fiber Optics

1) Critical angle is which of the following?

39) A light beam enters water at an angle of.incidence of 3r. Determine the angle of refraction.Answer: 26.9 ° 37"DM2 I

I

c;l Y\G)(.=- 'r\ l.\1\,• -I

~ll\.

A) 8i = Or

B) (/.zll.l) (sinOl/sinez) = 1

C) = (dIn)D) I./lm

QJ arcsin(nz/nV) ( -......Answer: EDiff: 1

2) The critical angle in ordinary glass isA) greater than 45°.B sin 1/n .

less than 45°.

Answer: CDiff: 1

-"

Answer: The second index n2 =1.00Diff: 1

~ light beam with wavelength 440. nm in a material then enters air and its wavelength becomes~~nm." (a) What is the index of refraction for the material?q (b) At what angle with the surface will the beam be totally reflected back in the material?

A. : a) 1.31 h -.:-!1 ..s(V\Cl"r r)40.30 ~ 1\"1.- >-' /. ,(S.17iI01",~ 1\ 31Iff: 'l- \\ 1.::' 1'\• .J. :~006~.-A ~40XIO-, '"J ~ Jj

4) The critical angle is given by sinc(1/n,) for what conditiO~? ec..: $,'1\ I ~ •• S I'/I.-tat')() '- ":.111, (, • .----=...

&¥l

Answer: ADiFf: 1

6) When TOTAL REFLECTION occurs at a surface, the incident angle must be in the substance withthe higher

Answer: ADiff: 1

@n optical fiber is 1.00 meter long and has a diameter of 20.0 f1m. Its ends are perpendicular to itsaXIs. Its index of refraction is 1.30.What is the minimum number of reflections a light ray entering one

~

Will make before it emerges from the other end? -I 1\ . ~'Gr?0~~ , . 1\ /\ r' S i 1\ ~ c SI ~

A) 2.42 x 105 511\ 9,- :- _'1. \,:;IL r-, 1,30B) 2.56 x 105 h, tf) = SO'C) 2.02 x 105 (..

D) 1.85 x 105

E) 2.85 X 105

Answer: DDiff: 3

8) Light in a transparent material (index of refraction 1.333)strikes the boundary with anothertransparent material (n = 1.010) G : 7 $1Y\.6"'00- ~

(a) What is the critical angle for total internal reflection? c. I t01 _ ,-I ~~ _ ~. ',,;,' / J.. 0\ Q.\C7t~q~\~~\~,G ~y

~y what per~ent does the wavelength change going from the 1st to the 2nd material?

Answer: (8)49,26° c.,1L\ t> \(b) 32,0% _~ I~ .0J- ~ ~Diff: 3 r ~ \ 2.- ~ 1-

9) For certain angles, TOTAL INTERNAL REFLECTION can occur when light triesi,pass from onemedium to another which has t \ I

A alar e 'ooex..of-l: ' M-u.!. b-L ~"At\ '. OM So Owev-. B) a smaller index of refraction. - \- /t

t e same Index of refraction. 'lU 'or, r\:l. <. f"IlD) an index of refraction which is sin"(45°).E) an index of refraction which is sin'\n).

Answer: BDiff:/

1\1--\\,

Answer: DDiff:/

10) The critical angle for a beam of light passing from water into air is 48.8~ This means that alllight rays with an angle of incidence greater than this angle will be

A) absorbed,B) totally transmitted.C' and partially transmitted.) totally reflected.

11 ) A ray of light (inc) enters a 45° - 90° glass prism from air (bottom left), as shown.

B c

A D

100 E

In what direction does the light re-emerge back into the air?A)DB) BCiA

~~

Answer: EDiff: 2

13) Mirages are due toA) reflection.B) polarization.cg) refraction]D) dispersion.E) total internal reflection.

Answer: COirf: 1

~he end of a cylindrical plastic rod is polished and cut perpendicular to the axis of the cylinder.~rmine the minimum index of refraction so that a light ray entering the end of the rod will always

~ be totally internally reflected within the rod, i.e., it will never escape the rod until it comes to the other

~end. Sl'f\eG:::~ f)c-'>tlsoA~s.wer: 1.414 "t\, ~-- ..•.•--'i-1sJOfff.2 ./\ _ 1'\"<- l.o~ 4-' .

i\{. - -..__ I

__ 5,; A.Ge.. S/'j";0{Jlf \ '

14) A light ray enters a glass enclosed fishtank. From air it enters the glass at 20.0° with respect tothe surface, then emerges into the water. The index for glass is 1.50 and for water 1.33.

8, ~1()'-20" :..70.(a) What is the angle of refraction in the glass? e = 7(b) What is the angle of refraction in the water? tJ .(c) Is there any incident angle in air for which the ray will n'bf enter the water due to total

internal reflection? r\ < "/\.,, _ (\ ,,. A,.;> • ~b',- l_' "'1. I AliI..

Answer: (a) 39° fu. ~lh19, ::: 7lv'\ez. (f' Gi.A~(b) 45° rh ~ I

(c!no S(~I~ .•s\"~f~ Gl:~9° b~ W~

Offf: 3 ""'U'&/f~iIl70'Yh!2 J'~-'{::{~(.5J}3r~'iS()15) Fiberscopes are based on the physical ~keno ena called

Sl~ ::n1.A) diffusion. V\,B dis ersion.C total internal re ec 10

D) absorp Ion.E) polarization.

Answer: COiff: 1

$c..3t*J~t2°8)-=(;;20

1\,( (;-?D'2. - • I - ,

16) A light ray emerges from the bottom of a 45° glass prism Into air, as shown in the sketch.

A D

From which direction was the ray incident on the prism?A)AB) BC)C

~Answer: 0Diff: 2

17) What is the critical angle for light traveling from crown glass (n; 1.52) into water (n; 1.33)?

A) 66°B) 42°C) 5rD) 48°E) 61°

Answer: EDiff: 2

£"\ VI "l..Slf\. Dc ~ -'f\,

e ' -'tfl 1- ) - '~G'3..3) t01 6c...= SLI\. - .. ,5l/\ - -1"1, .•n..

22.5 Dispersion

1) The person who proved that white light is composed of light of different colors isA) Willebrod Snell.

. Hu ens.C) Isaac Newto

era Electric.E) Thomas Edison.

Answer: CDiff:J

B l.U.C Cttl ~H F(2..t~'J ~ eNOS I'NJU7HPrf\J {L(j).

2) In common transparent media, as the frequency of light increases, the index of refraction( A) increases. ]B) stays constant.C) decreases.D) varies as the sine of the incident angle.

Answer: ADiff: 1

4) You see' bow ifA) the sun is behind ou. ~N ~

the sun is in front of you.C) the sun is 90° to the side.D) the sun is 180° to the side.

fU\lt.J ~s A I-l t~D -r /IiL If MM- CAt-..) fHJ It l£ F'~ "IO-l.{l..'

Answer: A

Diff: 1

5) White light isA) dichromatic. 1-wo ~L~B) monochromatic. 0"- -t- 4>,l(jr

C) achromamtic. 1\.-0 (0 Iw \t?) polyclli Omabc.J~ r"Yv.I.~ Go \ 0"--1

Answer: DDiff: 1

6) Rainbows are caused by sunlight beingA) dispersed. .6TI) dispersed, refracted & refJectedJC) refracted. R::D) reflected.E) refracted & reflected but not dispersed.

Answer: BDiff: 1

Answer: BDiff: 1

7) The color on the outer edge of the primary rainbow iswhite

B) reVI e

D) yellowE) green

8) White light, coming from me ium 1 (index of refraction n,), will disperse upon entering medium 2(index of refraction nz) when

A) (nz > n,).B) (nz < n,).C nz:: n, .D) (nz > n,) or (nz < n,).

Answer:DDiff: 2

9) When the index of refraction of a transparent material varies with wavelength, the material exhibitsA) density variation. '1B " n.C dispersion. co!ur) ref ection.

E) total internal reflection.

Answer: C

Diff: 1

Answer: CDiff: 1

10) Which of the following colors undergoes the greatest REFRACTION when passing from air intoglass?

A) yellowBred) blueorange

E) green

11 ) White light isA) light of wavelength 550 nm, in the middle of the visible spectrum.

l+UoU6ed-to-tl. . t light.ed reen, and blue light -

0) a mixture of all frequencies. 0 r- Vl~l 8L6 UCLt7 re opposite (or comp ementary color) of black light.

Answer: C or 0Diff: 1

Answer: BDiff: 1

12) Laser light is \. . ible in air. - ~I.l" !)-L tf'o.t.'€,.monochroma IC. ~ ~ (I I

C) isperslve. "'"' 1\ ot (w-l _ j' t- is w: e.hJ..0) created by total reflection. e~~V' lCl tI -tf'u. e.-j .

13) When white light enters a more optically dense medium than that from which it came, the greencolor c acts 'rvI.()U the red color component.

A) more thane sa e as

C) less than

Answer: ADiff: 1

14) White light is

Answer: BDiff: 1

15) Which color of light undergoes the greatest refraction when passing from air to glass?

(~rrI

17) A beam of white light is incident on a thick glass plate with parallel sides, at an angle between 0°and 90° with the normal. Which color emerges from the other side first?,,~<t\~(

ll;uJ > u;,VJ.~7

Answer: D RDiff:/ /

~16) More of the rainbow can be seen from the ground w'~en

A) the sun is higher.B here is an ecli se.C) the sun is lower.

. ron of you.

Answer: CDiff: 1

A) red

green lC) violetD) none of the other choices; all colors emerge at the same time

Answer: ADiff: 2

~eJ.. V Ie..I-18) The color on the outer edge of a rainbow is for the primary rainbows and ~for thesecondary.

A) violet, red. et;-viel

) red, violetreen, yellow

E) red, red

Answer: CDiff: 1

19) The index of refraction for a certain material is 1.399 for red light and 1.432 for blue light. Find theangle separating the two refracted colors if the:

(a) angle of incidence is 30°.(b) angle of incidence is 60°.

Answer: (a) 0.500(b) 1.040Diff:3

23.3 Lenses

1) A lens projects an image of a man as seen in the figure. Rays marked A, B, and C travel to thelens from the man's ear. I

A

\Draw the three refra ted r ys as they proceed to theaxis, B goes through enter of the lens, C proceeds tomarked f is the focal p 'nt of the lens.Answer:

Diff: 3

ting that A is parallel to thethe lens, and the point

Answer: 0 (most likely A or C, but can't be sure.)Diff: 2

2) In a single-lens reflex camera the lens-film distance may be varied by sliding the lens forward orbackward with respect to the camera housing. If, with such a camera, a fuzzy picture is obtained, thismeans that

A) the lens was too far from the film.B) too little light was incident on the film.C) the lens was too close to the film.D) one cannot say which of the other reasons is valid.E) too much light was incident on the film.

~ 0" 3 (.H.\ J0 ::48"", ~ t: t 2Q.....3) A 3.0 cm tall statue is 48. cm in front of a biconvex lens (focal length 20. cm).

(a) Is the image real or virtual? ..L L \ 0/11\; - J, t. "I(b) How far is the image from the lens? f :: ct +-J.U ,n - ~ "I J.

-1--'.J _1 'Ji= ([a"lii<..) f3'f0 .(c) Is the image upright or inverted? f) d() - de:. tt8L•.•.~ c~(d) How high is the image? t I ~ J >.:f--__ ,J ~ l 0

Answer: (a) real ({J.) /-il.) d,.:. V\\::. -J.,' _ - 31{"",

i~?i~~~~ed ffA) d. r_- 4Bcn1 ,7~;~t{It~)(d}-2.1cm I!. - - ~ - -0.7/ ) ~07

Oiff:3 dl;-r I \v\Vi,Lrro) •.....~O .IJ~L.----- 2. I'M5) A slide projector is designed with its lens 6.0 m from the screen. The projected image is 1.5m

square of a slide object 2.5 cm square.(a) What is the object distance from the lens?(b) What should be the lens focal length?(c) What is the lens POWER?

Answer: (a) 10. cm(b) f= 9.8 cm(c) 10.2 Diopters

Oiff:3

6) The image of the rare stamp you see through a magnifying glass isA) always the same orientation as the stamp.B) always upside-down compared to the stamp.C) either the same orientation or upside-down, depending on how close the stamp is to the

glass.D) either the same orientation or upside-down, depending on the thickness of the glass used.

Answer: C (although D is true to some extent)Oiff: 2

9) Consider a converging lens forming an image on a screen. What property of the image would beaffeeled by covering the top half of the lens?

Answer: It would be half as bright since half of the light gets through the lens. Same image.Oiff: 2

10) A lamp is placed 1m from a screen. Between the lamp and the screen is placed a converging lensof focal length 24 em. The filament of the lamp can be imaged on the screen. As the lens position isvaried with respect to the lamp,

A) a sharp image will be seen when the lens is 60 cm from the lamp.B) a sharp image will be seen when the lens is 40 em from the lamp.c) no sharp image will be seen for any lens position.D) a sharp image will be seen when the lens is halfway between the lamp and the screen.E) a sharp image will be seen when the lens is either 40 em from the lamp or 60 em from the

lamp, but not otherwise.

Answer: EDiff: 2

~hen an object is placed 60. cm from a converging lens, it forms a real image. When the object ismoved to 40. cm from the lens, the image moves 10. cm farther from the lens. What is the focallength of the lens? d. ~(;OLM

a. 42cmb. 50cmc. 40cmd. 20cme. 30cm

Answer: ADiff: 2

15) Is it possible to see a virtual image?A) no, since virtual images do not really existB) no, since the rays that seem to emanate from a virtual image do not in fact emanate from

the imagee) yes, since the rays that appear to emanate froll1 a virtual image can be focused on the

retina just like those from an illuminated object~ " I eJ ~'A.0) yes, since almost everything we see is virtua because most t ings do n t themselves give

nl reflect light coming from some other sourceE) yes, but only indirec y In e sense ale vlrtrra'''lnrn:ge1s" orme on a slieel a

photographic film, one could later look at the picture formed

Answer: 0Diff: 2

16) How far from a lens of focal length 50.0 mm must the object be placed if it is to form a virtualimage magni~size by a factor of three? M.:::.3 f' ::.-SO".. It'\.CA) 33.3J!lmJ I rB) 48.0 mm ~O =7. _I::: 1- fI-e) 38.3 mm -cd.. f cPt. doD) 42.2 mm .5 " C (j

E)54.4mm do 1_ -I 1 :.L~~~~f -if + do ~ 3Ji. \ st. s~.)\- 3JQ =-J~

Answer: A (\ ~ J D 2 (J ,Diff:2 f-= ~ ?{o=1f =~~~~17) A slide projector has a lens of focal length 150. mm. An image 100. cm x 100. cm is formed of aslide whose dimensions are 50.0 mm x 50.0 mm. How far from the lens must the screen be placed? 11 f- J,

f - 1St> I . I -100<",- -J . ..., .. 0A . 3 15 .. ""...... 11-, = ( OOe..... ~ I "~'" "" ~ '" t~ I't =.2--0. : ~nswer.. m ..L ~ .., . !Vt", C/"Diff:2 c1- ~ 7 f ~ ~1. 0 ,I T J..c _1- t ~_ '~ I J."

l . • J. 2£J.,J. do 241"\ 2c.l~f '~I-;- r}.(}«o -:::d,~wo thin lenses, of focal lengths f1 and f2, placed in contact with each t' er are~e lens of focal length

A) f1 + f2. f fB) 1/ (f1 + f2). t \ I L

Answer: CDiff: 2

21) How does the thickness of a lens relate to it being converging or diverging?

Answer: A converging lens is thicker at its center than it is at its edges and a diverging lens isthinner at its center than it is at its edges.

Diff: 1

22) A camera with a telephoto lens of focal length 125.mm is used to take a photograph of a plant1.8m tall. The plant is 5.0 m from the lens.

(a) What must be the distance between the lens and the camera film if the image is sharplyfocused?

(b) How tall is the image?

Answer: (a) 128.mm from lens to film(b) 45. mm tall

Diff: 3

23) Where must an object be placed with respect to a converging lens of focal length 30 em if theimage is to be virtual, and three times as large as the object?

Answer: 20 em from the lens

Diff: 2

25) In using ray tracing to graphically locate the image of an object that is placed in front of a lens,describe three simple rays that you could draw that pass by the head of the object.

Answer: Ray 1: the vertex ray; i.e., the ray passing through the center of the lens, which emergesundeflected. .

Ray 2: the parallel ray; i.e., the incoming ray parallel to the main axis, which is then refractedalong a path that extends to the focal point.

Ray 3: the focal ray; i.e., the ray drawn toward the focal point, which is then refracted parallelto the main axis.

Diff: 3

26) How far from a 50. mm focal length lens, such as is used in many 35. mm cameras, must anobject be positioned if it is to form a real image magnified in size by a factor of three?

A) 58. mmB) 76. mm

C) 46.mmD) 67. mmE) 52. Mm

Answer: DOiff:2

28) An object is placed 9.5cm from a lens of focal length 24 cm.(a) Where is the image formed?(b) What is the magnification?

Answer: (a) 16=from the lens on the same side as the object(b) m = 1.7 .

Oif/: 3

29) The images formed by double concave lensesA) are always virtual. 'N 0 I NO I vB could be real or virtual, b~eal when the object is placed at the focal point.C) coul reai-or-virtuat, Itllt'i'rfffi1ds on whether, the object distance-iS""smal er or greater t an

the focal length.are always rea. "p () •

Answer: COiff: 2

2) Spherical lenses suffot . and chromatic aberration.spherical aberration, but not c ro IC a erration.

C) neither spherical nor chromatic aberration.D) chromatic aberration, but not spherical aberration.

Answer: AOiff: 1

3) If the refractive index of the glass in a lens varies with wavelength, then which of the followingresults?

A) spherical aberrationB) light scatteringC) total reflectionD) asti matismc romatic aberration

Answer: EOiff: 1

B) mirrors but not lenses.C) lenses but not mirrors.

Answer: ADiff:/

Answer: CDiff:1

~hen two parallel white rays pass through the outer edges of a converging glass lens, chromatic~ation will cause colors to appear on the screen in what order, from the top down?

A) red, blue, red, blue~ B) blue, red, blue, red- C) red, blue, blue, red~ D) blue, red, red, blue

E) blue, blue, red, red

Answer: DDiff:2

Answer: CDiff: 1

7) Compare two diverging lenses similar except that lens B is rated at 20 Diopters, whereas lens A israted at 10 Diopters. The focal length of lens B is

A) twice the focal length of lens A._ B)..one-tolJdh of tb th of lens A.C on - f of the focal length of lensD) 1/..j2 of the foca eng 0 enE) four times the focal length of lens A.

8) Why do large aperture telescopes use a mirror instead of a lens to focus light?

Answer: Large mirrors are much cheaper than lenses (the largest lens has a 1 m diameter) andmirrors have an added advantage of no chromatic aberration. Lenses have to be supported from thesides, so they can deform. Mirrors can be supported from underneath, so they won't deform asmuch.

Diff: 2