A student wants to use a lens and project a picture of a candle flame onto the walls of the school lab. 

(i) Which type of lens should be used and why? 

(ii) How far away from the lens focal length "F" should he set the candle flame in order to get the enlarged picture on the wall? 

(iii) Draw a ray diagram to illustrate how the image is created in each circumstance. 

(iv) Is it possible for him to reflect a diminished image of the candle flame onto the same wall using this mirror? If the answer is yes, explain how; if the answer is no, explain why.

(i) He should use a convex lens as it forms real images. 

(ii) He should place the candle flame between 𝐹 and 2𝐹 (the focus and centre of curvature of the lens) to get the magnified image on the wall, while the diminished image is obtained when the object is located at a distance greater than 2𝐹. 

(iii) The ray diagram for the formation of the magnified image is shown below:

The ray diagram for the formation of the diminished image is shown below.

(iv) Yes, he can use a concave mirror in this case, also. A diminished image is formed if the candle is placed beyond C.