Question

At what distance, in terms of focal length ‘f’ of the mirror, should he place the candle flame to get the magnified image on the wall​

Answer 1

Answer

the focal length of plain mirror is at infinity so you have to keep the image at length less than focal length

and if it is concave mirror then you have to place it at the distance less than its focal length

Explanation:

I have given to cases because you have not specified which type of mirror is used