Part 1. A small lightbulb 2.4m from a concave mirror gives a real image 6.8cm from the mirror. Find the mirror's focal length. Where will the image be if the bulb is moved to 3.9m from the mirror?
Part 2. A dentist's mirror produces an upright image of a tooth, magnified three times, If the dentist holds the mirror 2.0cm from the tooth to achieve this magnification, what's the mirror's focal length?