A 2.0--tall candle flame is 2.1 m from a wall. You happen to have a lens with a focal length of 37 cm .
How many places can you put the lens to form a well-focused image of the candle flame on the wall?
For each location, what are the height and orientation of the image?
The Attempt at a Solution
So I think there are 2 places you can place the lens because s'+s=210cm and s' and s are interchangeable or something like that. I'm not quite sure though.
But then for the second part, i found the heights to be .65 and 6.2 cm but either one or both are wrong. I know I have to find the values for s and s' and I'm not quite sure how to do that. I thought s' would just be 2.1 but how can you have two values for it then?