Converging Lenses Graphical Analysis By Chris Cho and Dan
Fan
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Purpose Determine the relationship between object distance and
image distance for real images produced by a converging thin lens.
Determine the relationship between object height and image
height.
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Hypothesis Object distance is inversely proportional to image
distance. Object height is directly proportional to image
height.
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Materials Cart Track White Screen Converging Lens Light Source
Cut-out Arrows of Various Sizes on Cardboard Cut-out Number 4 on
Cardboard Meter Stick Chris Mom
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To Find the Focus Obtaining the Focus length. 1. Place the
screen at a given length on the cart track so that there is enough
room to place the converging lens on the side that points toward
the window. 2. Point the apparatus toward the window and locate a
specific object in the far distance. 3. Observe the image on the
screen and focus the image by adjusting the distance between the
screen and the lens. 4. When the image is perfectly focused,
measure the distance from the screen to the lens and this will be
the focus length.
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Focus Diagram
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General Lab Procedure 1. Start by placing the converging lens a
total of 15 focal lengths away from the object (the distance
between the lens and the object is the object distance). Adjust the
screen so that the image becomes clear. (the distance between the
screen and lens is the image distance. Shorten the object distance
by 1 focal length increments and adjust the screen while measuring
the image distance and object distance each time. Shorten the
object distance by smaller increments once you approach a distance
of 2 focal lengths. 2. Move the converging lens 1.5 focal lengths
away from the object. Place a cut-out arrow in front of the light
source and adjust the image distance until the projected image is
clear. Measure both the real and the projected arrows length. Do
the same with arrows of varying sizes. Repeat the same procedure
with a 2.5 focal length object distance.
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Distance Exploration Table
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Image Distance vs Object Distance
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Image Distance vs 1/ Object Distance
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1/ Image Distance vs 1/ Object Distance
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1/ Image Distance vs 1/ Object Distance Mathematical
Analysis
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Image Height vs Object Height Table
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Image Height vs Object Height Graph
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Image Height vs Object Height Analysis
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Drawing Ray Diagrams Drawing Ray Diagrams: Draw a ray from a
point on the object parallel to the principle axis to the center of
the lens. Draw another line extending from that point through the
foci on the opposite side of the image. (can be done because of the
definition of focus) Draw a second ray from that point through the
point in which the principle axis intercepts the lens. Draw a third
ray through the focus to the lens. Draw another line extending from
that point parallel to the principle axis. The point of
intersection is the corresponding image point to the original
object point.
