11• Concept quizzes 1-4Physics 1230: Light and ColorConcept quizzesConcept Quiz #1 (5 questions)1. Which of the waves atright has the largestwavelength?2. Which of them has thelargest frequency?3. If wave (a) and wave (c)are at opposite edges ofthe spectrum of visiblewavelengths (e.g., arainbow), which wave isseen as red when the rayenters your eye?a), b), c), or d) none of thema)b)c)2Concept Quiz #1 (Cont'd)4. The wiggling waveform ina light wave representsa) The various strengths anddirections of an electric forcefield at different points onthe ray at a given instantb) The vibrations of air or glassmolecules as light movesthrough air or glassc) The oscillations of electronsin the medium throughwhich the light wave ismovingd) Resonances in atoms in themedium through which thelight wave is moving.e) All of these5. The light from an ordinaryincandescent light bulbappears white becausea) A current of eletrons excitesa resonance in atoms at thefrequency of white light.b) A current of electrons excitesresonances in atoms at manydifferent frequenciescorresponding to manydifferent colorsc) A current of electronswiggles at the frequency ofwhite lightConcept quiz 26. Which pinhole camerahas the largest image ofAlex at the back of thecamera?a) Camera Ab) Camera Bc) Camera Cd) They are all the same sizeABC3Concept quiz 27. Which pinhole camerahas the largest image ofAlex at the back?a) Camera Ab) Camera Bc) Camera Cd) They are all the same sizeABCConcept quiz 28. How many images ofAlex does Bob see?a) 0b) 1c) 2d) 3e) 4Perfect mirror surfaceAlexBob4Concept quiz 29. Does the fish in the lakesee an image of therunnera) Lower than she actually is?b) Where she actually is?c) Higher than she actuallyis?d) The fish doesn't see animage of the runner at alle) The fish sees two imagesof the runnerTop of lakeConcept quiz 210. The light and fish areboth underwater in thelake. Where does thefish see the light and/orthe image of the light?a) Higherb) Lowerc) Where the light actually isd) (c) and (a)e) (c) and (b)Top of lake5Here is how we use those rays to find theimage of an object in a concave mirror• Where is Alex's image when he is between thecenter and it's focal point?• Let's find the image of his nose– Here is a ray of type 1 from his nose reflectingoff the mirror– Here is a ray of type 3 from his nose reflectingoff the mirror– The image of the nose is at the intersection ofreflected rays of type 1 and type 3. Why?– Why haven't we used a ray of type 2?• Here is an approximation* to Alex's image– Is it (a) real or (b) virtual?– Magnified or reduced?11. From which points can your eye seeit?a) From all points (A, B, C)?b) From A and C, but not B?c) From B and C, but not A?d) From A only?e) From C onlyCenterFocalpointMirrorsurfaceAxisABCCONCEPT QUIZ 3What happens to his image if Alex iscloser to the mirror than the focal point?CenterFocalpointMirrorsurface• Draw rays of type 1 and type 3 fromhis nose to the mirror• The reflected rays will never intersectbehind Alex since they diverge behindhim• However we can extend the reflectedrays behind the mirror where they dointersect– The image of Alex's nose is at theintersection of the backward extendedreflected rays12. Is it real (a) or virtual (b)?13. Reduced (a) or magnified (b)?14. Right side up (a) or inverted (b)?15. Can Alex see his own nose?[ yes (a), no (b) ]• Here is the whole image–This is a magnifying mirror(for shaving or cosmetics)CONCEPT QUIZ 36Concept quiz #416. At right is Alex and his(real) image formed by aconverging lens which isnot shown. The positionof the lens can be foundbya) Drawing a ray of type 1b) Drawing a ray of type 2c) Drawing a ray of type 3d) The position of the lenscannot be found bydrawing raysConcept quiz #417. Can we find the focalpoints of this lens by ray-tracing?a) Not without moreinformationb) We can find the onebehind the lens (F')c) We can find the one infront of the lens (F)d) We can find them bothF F'7Concept Quiz #4 (cont'd)18. At right is an arrow and its same-sizeinverted image formed by aconverging lens of focal length 10cm. Where must an identical secondlens be placed to get a right-side upreal image of the same sizea) 10 cm in back of the lensb) 10 cm in front of the lensc) 20 cm in back of the lensd) 30 cm in back of the lense) 40 cm in back of the lensf = 1020 20f = 10F F'front backConcept Quiz #4 (cont'd)19. Can a virtual image ever bephotographed with yourcamera?a) Yesb) No'8Concept Quiz #4 (cont'd)20. At right is Alex's virtual image10 cm behind a converging lensof focal length 5 cm. Where willthe real image of Alex be?a) 4 cm in front of the lensb) 5 cm in front of the lensc) 6 cm in front of the lensd) 8 cm in front of the lense) 10 cm in front of the lensFF'f = 5101/f2 = 1/xo + 1/xif =