LENSES TEST (100 marks in total)

1. Draw a diagram showing how an image is formed in a diverging (concave) lens. (10 marks)
   
   
2. An object 10 cm from a convex lens forms a virtual image 30 cm from the lens.
   
   Calculate the focal length of the lens. (10 marks)
   
   If the height of the object is 0.2 cm, find the height of the image. (5 marks)
   
   
3. You carried out an experiment to measure the focal length of a converging lens.
   
   Draw a labelled diagram of the apparatus that you used in the experiment. (12 marks)
   
   Describe how you found the position of the image formed by the lens. (6 marks)
   
   What measurements did you take? (9 marks)
   
   How did you get a value for the focal length of the converging lens from your measurements? (9 marks)
   Give one precaution that you took to get an accurate result. (4 marks)
   (2005 ordinary level)
   
   
4. A convex lens has a focal length of +20 cm. Find its power.  (5 marks)
   
   It is placed in contact with a concave lens of focal length -50 cm.
   Find the power of the combination. (5 marks)
   
   
5. Name
   (a) the transparent window at the front of the eye (5 marks)
   (b) the light sensitive tissue at the back of the eye (5 marks)
   (c) the coloured part of the eye. (5 marks)
   
   
6. (a) What is meant by the power of accommodation? (5 marks)
   (b) What kind of lens is used to correct short sightedness? (5 marks)