Procedure and Data

Quantitative Data

• Place a converging lens between the object and a screen.
• Move various elements until you have a real image clearly projected onto the screen.
• Record the labeled focal length of the lens, image distance, object distance, image height and object height.

Labeled focal length of lens, __10cm

Object and image distances and heights:

13.3	41.2	4.2	13.2

Warning: Record the distances and heights using the correct sign conventions. Look these up if you're unsure.

Qualitative Data

There are four versions of this set up to explore:

1. Use aconverging lens and place itcloser than the focal length away from the lightbox.
2. Use aconverging lens and place itfarther than the focal length away from the lightbox.
3. Use adiverging lens and place itcloser than the focal length away from the lightbox.
4. Use adiverging lens and place itfarther than the focal length away from the lightbox.

In each version of the setup, check four qualitative aspects of the image formed.

• Can you see a clear image form on the screen at any distance?
• Can you see an image if you look through the lens?
  • Remove the screen to see.
  • If there was an image on the screen before you removed it, stand at least behind the lens to see through it toward the object.
• Is the image you saw (either through the lens or on the screen) inverted or upright?
• Is the image larger or smaller than the object?

Scenario	Image seen on the screen? (Yes/No)	Image seen looking through lens? (Yes/No)	Inverted or upright?	Larger or smaller?
Converging lens, object within focal length	Yes	Yes	Inverted	Larger
Converging lens, object outside focal length	No	Yes	Inverted	Smaller
Diverging lens, object within focal length	No	Yes	Upright	Smaller
Diverging lens, object outside focal length	No	Yes	Upright	Smaller

Results

Quantitative Data

• Calculated focal length of the lens, ________________cm
• Measured magnification,
• Theoretical magnification,

Qualitative Data

• Based on your qualitative data, decide if the image is real or virtual.

Scenario	Real or Virtual
Converging lens, object within focal length	Real
Converging lens, object outside focal length	Virtual
Diverging lens, object within focal length	Virtual
Diverging lens, object outside focal length	Virtual

Sample Calculations

• Show at least one example calculation of each of the quantities below using your own data in the space provided.
• Indicate what data you are using in your example.
• If necessary, you can insert a photograph of clear, well lit, properly oriented, handwritten work.

1. Calculated focal length, fcalculated

1. Measured magnification, Mmeasured

1. Theoretical magnification, Mcalculated

Discussion

• The expected answer length is about a paragraph unless indicated otherwise.

1. Real images were not common in the Qualitative Data section of this lab.

1. What is a "real" image? What does it mean for an image to be "real"?

1. Which of the two broad categories of lenses used in this lab was never able to produce a real image?

1. Explain why the design/shape of the lens in your previous answer prevents it from ever producing real images.If a light ray diagram assists your explanation, feel free to include one.

1. If this category of lens is limited to producing only virtual images, then why does it even exist? What real-life applications could it provide?Make friends with Google for this question if you'd like.