# Phys 320 ilab (o) experiment 5

PHYS320 iLab (O) Experiment 5
Object and Image Distances for a Lens and Mirror
DATA SHEET
Name: __________________ Date: ___________
4 questions @ 1 point each; 9 questions @ 2 points each; and 2 questions @ 4 points each. 30 points total.

Prediction
1. What kind of image will you see through a convex lens? What factors might affect the size of the image? (1 point)
2. What happens to the image if half of the lens is covered? (1 point)
3. Draw a ray diagram below for a convex lens with a focal length of 3 cm. Place the object at 5 cm with a height of 1 cm. (2 points)

Is the image real or virtual? Is the image upright or inverted? How does the size of the image compare with the size of the object?
4. Draw a ray diagram below for a convex lens with a focal length of 5 cm. Place the object at 3 cm with a height of 1 cm. (2 points)

PHYS320 iLab (O) Datasheet

Page 1

Experiment 5

Is the image real or virtual? Is the image upright or inverted? How does the size of the image compare with the size of the object?
Explore
5. Write a description of what happens to the image size when you change the position of the lens. (2 points)
6. Describe whether the image is upright or inverted. (1 point)

7. What happens to the image if half of the lens is covered with an opaque object? (1 point)

Data
8. Fill in the data table and paste the graph for the convex lens here. (4 points)
Object distance (s)

Image distance (s)

PHYS320 iLab (O) Datasheet

Page 2

Inverse object
distance (1/s)

Inverse image
distance (1/s)

Experiment 5

9. Fill in the data table and paste the graph for the concave mirror here. (4 points)
Object distance (s)

Image distance (s)

Inverse object
distance (1/s)

Inverse image
distance (1/s)

Analysis
10. The graphs show inverse image distance (vertical axis) versus inverse object distance (horizontal axis). The graph also shows a curve fit for the data. Is image distance directly or inversely proportional to object distance? Write a description of the graphs. (2 points)
11. For the lens and the mirror, what are the slope and the y-intercept from the linear fit to your data? (2 points)
12. From the line fit, what is the focal length of each lens and mirror? Compare your measured value with the nominal value written on each by calculating a percent difference. (2 points)

Questions
13. What value does the image distance approach as the object distance becomes larger? (2 points)
14. What value does the object distance approach as the image distance becomes larger? (2 points)
15. Where would you place the object to obtain an image as far away from the lens as possible?
Where would you place the object to obtain an image located at the focal length of the lens (100 mm)? (2 points)