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Unformatted text preview: Lab 10 The Simple Lens & Lens Systems Lab 10 Report (100 points)
I " 1:” ' PHYS 1214 5323169 Section: Name: /' / ,
'1 J a 53‘s...
Day and lime: Mfg/M , i’%%€"~i'=l** 3 \. I my Station Checkin: L/ PART I. Determining the Focal Length of Converging Lenses (10 pts) Referring to the drawing below, parallel rays of light are refracted to the focal point of a
converging lens. Using this phenomenon is one of the easiest ways to determine a value
for the focal length of a converging lens and to determine which of the two converging
lenses used in Parts I and II has the longer focal length. l<——— f——> 0 Select a distant light source in the lab. Use each lens focus the light from this
source onto a piece of paper or the wall. 0 The lens that focuses the image of the light source furthest from the lens is the
lens with the longer focal length. Lens A has a focal length of 20 cm. The other
converging lens (Lens B) has a focal length of 10 cm. Determine the focal
length of each lens 0 Place the screen and the light source as far away from each other as
possible. Place the lens in between and focus the image on the screen.
Measure the focal length. LensA: 20'” cm
LensB: “7'50 cm I How accurate are your readings? Find the percent error of your measured focal len hs for each lens. no, a n 1.3:
g A: Ms M : a.)
LensA: 4’6 %
. ‘l. 0 (5" EEOE ’50
Lens B. % ‘T hi} .3 Lab 10 The Simple Lens & Lens Systems PART 11. Image Formation of a Converging Lens (65 pts) In this part of the experiment, you W111 1nvest1gate image‘fo, ‘ anon}? ‘ magnlﬁcatlon
when the object, the light source, is placed at various distances 3m lens A. Note: Use
the observed focal length from part I for the rest of the lab. No credit will be assigned if
the sign conventions are not followed. The object is located a distance greater than two focal lengths from the lens. (27 pts) 0 Place the lamp on one end of the optical rail. 0 Mount lens A in the lens holder and place it a distance greater than twice the focal
length of the lens from the light source. 0 Place the screen on the optical rail on the side of the lens opposite the light source.
Slide the screen along the rail until a sharp image of the light source is formed on the
screen. 0 Using the scale on the optical rail, determine the object d i '70, l g cm
distance (i.e., the distance from the lamp to the lens). ° ———“— 0 Using the scale on the optical rail, determine the image d. ’2: o, cm
distance (i.e., the distance from the lens to the image). 0 Given the focal length of lens A is 20 cm and using the Z ‘3 measured object distance, use the thin lens equation to Calculated di 3 ' 5' cm
calculate the image distance. I Calculate the % difference between the measured and 0 . {7%}! . . Adiff %
calculated image distance Z Z . it —~ 2 ——— 7’“ 3:55:31} 2 {(51.3% LL32, ‘ I” 0 Using a ruler measure the object height and the image Object height a’ "‘4" cm
height. Recall that there is a sign convention when
measuring object and image heights. Image height ’“ 0‘ ‘3 cm 0 Calculate the transverse magnification. (show work) m = —3L  O . f/ g  ,. 20! a? \ o __
m ”' WSW “ h
, 0‘ g m = ——i ” A / 5’11 g
M '3 2?! S : 1'10 0 Calculate the percent difference between the two %diff I"! %
calculated magniﬁcations —'—"f—
x
W
/" xx! 134 Lab 10 The Simple Lens & Lens Systems Referring to the values obtained above and the appropriate ray diagram from the pre lab,
circle the appropriate answer for the following questions. a. dis (">0 <0 b. The image is a .«MEéQI image ertual ..... Image c. hi > 0 ’< 0 d. The transverse magniﬁcation m is > 0 W< 0 e. With respect to the object the image is upright inverted/w . f. The magnitude of the transverse magniﬁcation > 1 < m is The object located between one and two focal lengths from the lens. (27 pts) Place the lamp on one end of the optical rail. Mount lens A in the lens holder and place it a distance greater than one focal length
and less that twice the focal length of the lens from the light source. Place the screen on the optical rail on the side of the lens opposite the light source.
Slide the screen along the rail until a sharp image of the light source is formed on the screen. Using the scale on the optical rail, determine the object
distance (i.e., the distance from the lamp to the lens). Using the scale on the optical rail, determine the image
distance (i.e., the distance from the lens to the image). Using your measured focal length for Lens A and the
measured object distance, use the thin lens equation to
calculate the image distance. (show work) i r f» , H
I I I“. ~/.
*1 Calculate the % difference between the measured and
calculated image distance Using a ruler measure the object height and the image
height. Recall that there is a sign convention when
measuring object and image heights. 135 do 3/.6 di 5% I 6
Calculated di g a” %diff O» 66
Object height ’3  ‘5
Image height “ é‘ i cm cm cm % cm cm Lab 10 The Simple Lens & Lens Systems 0 Calculate the transverse magniﬁcation. (show work) ..  'l’ﬂ § , = _ d1 “ / If) 3
W‘ ’ 22:6 m do
.. — M h.
. m. M _ 1 ad I l‘ 3.;
PM 77"; m _ E— / 1}
0 Calculate the percent difference between the two %diff D, .3; 3 calculated magniﬁcations Referring to the values obtained above and the appropriate ray diagram from the prelab,
circle the appropriate answer for the following questions. 1. > 0 \‘g < 0 2. The image is a KTQ image ertual
“TMWW 7 ~ image 3 hi > 0 0 4. The transverse magniﬁcation m is > 0 “Kg(3%") \._.,..,.«"
5. With respect to the object the image is upright ,r’ﬁiiiverted I . . . ﬁgxwm—«g‘ (“WimmmWWH i
6. The magnitude of the transverse magniﬁcatlon ml /> 1 < 1 ls W The object is located less than one focal length from the lens. (11 pts) Place the lamp on one end of the optical rail. Mount lens A in the lens holder and place it a distance less than one focal length from
the light source. Place the screen on the optical rail on the opposite side of the lens as the light source
and slide it along the rail. Can you form a sharp image on the screen? (Circle your
answer below.) yrw—r'dg Yes No this.“ W From your observations is the image a real or virtual image? (Circle your answer
below.) Wraxwwww maul“.qu virtual imagnejﬂ)
“Nah—«H. NNNNN M.MM ' > real image 136 Lab 10 The Simple Lens & Lens Systems The image can be viewed by looking through the lens at the light source. Referring to
both what you see and the appropriate ray diagram from the prelab, circle the appropriate
answer for the following questions. 1. 2. dilS >0 The image is a . hi ; a K:
The transverse magniﬁcation m is a; A)
. I , .... “MWem“,
. With respect to the object the image 13 K“ upnght ,, ,\
N “FM The magnitude of the transverse magniﬁcation ImL/gT >
is 137 (56‘?) . (lirtTuE\\
real 1mage .
1mage \d/
<0 <0 inverted <1 Lab 10 The Simple Lens & Lens Systems PART III  Lens System I (25 pts) Below is the setup for a lens system consisting of lenses A and B. The object is located a
distance of 160 cm (that is 8 x fA) from lens A and lens B is located a distance of 30 cm
(that is f A+fB) from lens A. o For this lens system, accurately draw the ray diagram that will locate the image.
Refer to Figure 13 and/or Figure 14. Lens A Lens B l— fA—F fA+fFfgl Referring to the ray diagram, circle the appropriate answer for the following questions. / / . . . /” virtual 4
l. The ﬁnal nnage 1s a real image w/
2. hi is > 0 {1/ < 0 ““ 3. The transverse magniﬁcation m is > 0 4. With respect to the object the image is upright {inverted
5. The magnitude of the transverse magniﬁcation lml is > 1 l V 138 Lab 10 The Simple Lens & Lens Systems This lens system is an example of a Galilean telescope, used to observe very distant
objects. However this lab is constrained to ﬁt this system on the optical rail. Observed object and image heights Place the light source at one end of the optical rail. Place lens A near the other end of the optical rail, 160 cm from the light source.
Place lens B 30 cm from lens A (i.e., 190 cm from the light source). Looking through the lenses at the light source slide lens A until a sharp image of
the light source can be seen. Where does the image appear to be? Given that the ray diagram is correct, does
the image appear to be near lens A, between the lens and the light source?
Transverse magniﬁcation deals with the heights of the object and image. Measure
the height of the light source (the object) and enter it in the appropriate space
below. By opening both eyes and looking at both the image and lens A, how tall does the
image appear to be compared to lens A? Lens Ais’3‘ﬁ cm tall, compare the
height of the observed image to lens A. Estimate the height of the image, in units
of centimeters, and enter it in the appropriate space below. Calculate the transverse magniﬁcation and enter it in the table below. Using the ray diagram, measure the height of the object and image that was drawn
and enter these values in the appropriate spaces below. Using the heights measured from the ray diagram calculate the transverse
magniﬁcation and enter it in the appropriate space below. Ray diagram object & image heights Object height a 5 cm Object height Z’ § 0 cm
Height of the image I O ' l’ L cm Image height — / ’ 0 0 cm
Transverse , 0‘ W Transverse ,_ 0 I b!
magniﬁcation m a! m f: magniﬁcation m M: f: 2‘) W“: 9 :3 0 Compare your observed magniﬁcation with the value that you rickpected from
the ray diagram. Calculate the percent difference. (show work.) 0 ¢ M I.” O; “(a N u l r :5: y W e j w 59 4 ,. w mo » 74.3%.. ,2; g
f“ 139 ...
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 Spring '08
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