Plane Mirrors and the
Law of Reflection
Dee Luo and Jasmine Raskas
Part 1
Purpose: Determine the relationship between the angle of
incidence and angle of reflection.
Hypothesis: The angle of incidence is the same as the angle of
reflection.
Part 1 - Diagrams
Angle of
Incidence
Angel of
Reflection
Incidence Ray
Reflection Ray
Plane Mirror
Part 1 - Diagrams
Plane Mirror
Polar Grid
Light Source
Part 1 - Data
Part 1 - Graph
Part 1 – Mathematical Analysis
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θR Angle of Reflection
θi Angle of Incidence
θR ∝θI
θR = k θI
k = 0.997 ( calculated by logger pro)
θR = (0.997) θI
Part 1 – Error Analysis
Accepted Value: 1
Experimental Value: .997
• Absolute Error: |Acc Value-Exp Value|
|1-.997|
0.003
• Relative Error: |Acc Value-Exp Value|/Acc Value * 100
|1-.997|/1* 100
0.3%
Sources of Error:
• The angle of the mirror was not perpendicular to the laser.
• The markings on the given paper were not consistent.
Part 2
Purpose: Determine the relationship between the object
distance and image distance.
Hypothesis: The object distance will be equal to the image
distance.
Part 2 - Diagrams
P
l
a
n
e
Image
Image Distance
M
i
r
r
o
r
Object
Object Distance
Part 2 - Diagrams
Plane Mirror
Image Distance
Object Distance
Object
Part 2 - Data
Part 2 - Graph
Part 2 – Mathematical Analysis
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DoObject Distance
Di Image Distance
Di ∝ Do
Di=k Do
K=0.999 (calculated by logger pro)
Di=(0.999) Do
Part 2 – Error Analysis
Accepted Value: 1
Experimental Value: .999
• Absolute Error: |Acc Value-Exp Value|
|1-.999|
0.001
• Relative Error: |Acc Value-Exp Value|/Acc Value * 100
|1-.999|/1 * 100
.01%
Sources of Error:
• The mirror was difficult to see through
• It was hard to make the marking without moving the mirror
• The mirror was not completely perpendicular to the page
Part 3
Purpose: Determine the relationship between the object height
and image height.
Hypothesis: The object height will be equal to the image height.
Part 3 - Diagrams
Image
Image
Height
P
l
a
n
e
M
i
r
r
o
r
Object
Object
Height
Part 3 - Diagrams
Plane Mirror
Image Height
Object Height
Object
Part 3 - Data
Part 3 - Graph
Part 3 – Mathematical Analysis
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•
HoObject Height
Hi Image Height
Hi ∝ Ho
Hi=k Ho
K=0.995
Hi=(0.995) Ho
Part 3 – Error Analysis
Accepted Value: 1
Experimental Value: .995
• Absolute Error: |Acc Value-Exp Value|
|1-.995|
0.005
• Relative Error: |Acc Value-Exp Value|/Acc Value * 100
|1-.995|/1 * 100
.05%
Sources of Error:
• The mirror was difficult to see through
• It was hard to make the marking without moving the mirror
• The mirror was not completely perpendicular to the page