A student want to project the image of a candle flame on the walls of school laboratory by using a lens : (a) Which type of lens should he use and why ? (b) At what distance in terms of focal length 'f' of the lens should he place the candle flame so as to get (i) a magnified, and (ii) a diminished image respectively on the wall ? Draw ray diagram to show the formation of the image in each case.

A student want to project the image of a candle flame on the walls of

1.	A student want to project the image of a candle flame on the walls of school laboratory by using a lens : (a) Which type of lens should he use and why ? (b) At what distance in terms of focal length 'f' of the lens should he place the candle flame so as to get (i) a magnified, and (ii) a diminished image respectively on the wall ? Draw ray diagram to show the formation of the image in each case.
Answer» Solution :(a) The STUDENT should use a convex lens because only a convex lens can FORM a real image of the candle flame which can be obtained on the wall of school LABORATORY. (B) (i) The candle should be placed at a distance d, where `f lt d lt 2f`, to obtain a magnified image on the wall. Ray diagram is shown in FIGURE. (ii) The candle should be at a distance `d gt 2f` to obtain a diminished image of the candle on the wall.