What type of images can a convex lens make?

What type of image is always made by a concave lens?

How can you show that white light (say, sunlight) consists of seven colours?

Name the scientist who discovered that sunlight consists of seven colours.

State any two observations from everyday life which show that light travels in straight lines.

What did Newton demonstrate by his experiments with the prism?

What would a pencil look like when seen through a concave lens? Is the image real or virtual?

State where an object should be placed if the image formed by a convex lens is to be large, erect and virtual.