A diverging lens is used in:

Construct ray diagrams to illustrate the formation of a virtual image using (i) a converging lens, and

(ii) A diverging lens.

What is the difference between the two images formed above?

When an object is kept at any distance in front of a concave lens, the image foiled is always:

When sunlight is concentrated on a piece of paper by a spherical mirror or lens, then a hole can be burnt in it. For doing this, the paper must be placed at the focus of: