Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. (Physics Only)What is the focal length?
   • The distance from the lens to the principal focus is called the focal length.
2. (Physics only) What is the equation that links image height, magnification and object height?
   • The magnification produced by a lens can be calculated using the equation: magnification = image height / object height
3. (Physics only) What are the units for magnification?
   • Magnification is a ratio and so has no units.
4. (Physics only) What is the unit for image height?
   • Image height and object height should both be measured in either mm or cm.
5. (Physics Only) How can images by convex and concave lenses be represented?
   • Ray diagrams are used to show the formation of images by convex and concave lenses.
6. (Physics Only) How could you illustrate the similarities and differences between convex and concave lenses?
   • Drawing ray diagrams to illustrate the similarities and differences between convex and concave lenses.
7. (Physics Only) How are convex lenses represented in ray diagrams?
   • In ray diagrams a convex lens will be represented by: <-->
8. (Physics Only) How are concave lenses represented in ray diagrams?
   • [In ray diagrams] a concave lens will be represented by: >--<
9. (Physics Only) What type of images can be produced by convex lens?
   • The image produced by a convex lens can be either real or virtual.
10. (Physics Only) What type of image can be produced by concave lens?
    • The image produced by a concave lens is always virtual.
11. (Physics Only) How does a lens form an image?
    • A lens forms an image by refracting light.
12. (Physics Only) How is a convex lens used to focus an image?
    • In a convex lens, parallel rays of light are brought to a focus at the principal focus.