Which of the following statements is correct on the basis of the following information? 'A' always forms a virtual and erect image. 'B' forms a real and inverted image in most cases.

Objects like the sun are called luminous objects. Which of the following is the correct reason for calling them so?

Shadows are formed when an _______ object comes in the path of light.

If you are asked to project the real image of a well-lit painting on a wall, which one of the following optical devices would you select for this purpose?