Name one simple optical instrument in which the above arrangement of convex lens is used.

Explain why, a real image can be projected on a screen but a virtual image cannot.

Draw a ray diagram to show the formation of a real diminished image of an object by a convex lens. In your diagram, the position of object and image with respect to the principal focus should be shown clearly.

A convex lens has a focal length of 10 cm. At which of the following position should an object be placed so that this convex lens may act as a magnifying glass?

Which one of the following materials cannot be used to make a lens?