1State the three rules used for drawing ray diagrams of lenses.
2What is the difference between a real image and a virtual image? Give one example of each formed by a convex lens.
3Where should an object be placed in front of a convex lens to get a real, inverted image of the same size? Where does the image form, and where is this used?
4Describe the ray diagram for an object placed between F and O of a convex lens, and explain how this helps a hand lens enlarge small print.
5Why can a piece of paper catch fire when a hand lens is held still in sunlight above it?
6A convex lens has a focal length of 15 cm. A candle is placed 20 cm from it. Where is the image formed and what are its characteristics? Name a device that uses this arrangement.
7Why is the image formed by a concave lens always virtual? Describe the image and give one use.
8The film in a projector is loaded upside down. Why?
9What happens to the position and size of the image as a candle is moved from far away towards the focus of a convex lens?