SNC2D/15Name: ______

LAB – LOCATING IMAGES IN LENSES

Purpose:

To explore the characteristics of images produced by converging and diverging lenses.

Materials:

  • Converging Lens and support
  • Diverging Lens
  • Metre stick
  • Lamp
  • Paper Screen and support

Prediction: (To be completed BEFORE you complete the lab)(K/U: 1 mark)

Predict what will happen to the size and distance of an image as an object is moved closer to a converging lens. Use the space below:

Procedure:

Converging Lens

  1. Find the focus (F), for your lens
  2. Place the lamp so that the metre stick is exactly in line with the light as shown by your teacher.
  3. Once you know your focal length, place your lens at 2.5 times your focal length away from the lamp. Adjust your paper screen until the filament of the lamp is in focus. Record the length from the lens to your image in your observation table below.
  4. Record the characteristics of the image formed in terms of its size, attitude and type.
  5. Repeat step 3 and 4 for each of the remaining focal distances as shown in the observation table.
  6. Complete the rest of the calculations for each object distance and image distance, except the last one. Then using these values calculate the Magnification for each observation.

Diverging Lens

  1. Replace the converging lens with a diverging lens, and place at the appropriate focal length.
  2. Attempt to find the image formed by adjusting the location of your paper screen.
  3. Look into the diverging lens and describe the characteristics of the image formed and record in your observation table.
  4. Move the lens back and forth to see if there is a change in the characteristics of the image.

Observations: (C: 4 marks)

Converging Lens

Object distance (do) cm / Image distance (di) cm / Characteristics
Size Attitude Type / 1
do / 1
di / 1 + 1
do di / Magnification
(M)
2.5f=
2.0f=
1.5f=
f=

Diverging Lens

Characteristics
Size / Attitude / Type

Analysis Questions: (10 marks)

  1. How does the focal length for both sides of the lens compare? (I:1 mark)
  1. As the object moves closer to the lens, what regular changes occur in the size of the image? The distance of the image? The attitude of the image? (I: 3 marks)
  1. At what distance was it difficult, if not impossible, to locate a clearly focused image? (I: 1 mark)
  1. Where would you place an object in relation to the principal focus for a converging lens to form a real image? A virtual image? (I: 2 marks)
  1. How does the value of relate to the value of for the cases involving real images? (I: 1 mark)
  1. What is the relationship among the focal length, the image distance, and the object distance of a converging lens? (I: 2 marks)