I created this set of practice problems for my high school physics students when we study curved lenses (both convex and concave). This problem set includes 14 practice problems and a key with detailed answers worked out. The first page of practice problems has some general rules for solving convex and concave lens and both formulas required to solve the problems (thin lens equation and magnification equation).
Having a detailed key saves you time and also helps your students identify where they need more help.
I use this set of practice problems when teaching the following Georgia Performance Standard:
SP4. Students will analyze the properties and applications of waves.
b. Experimentally determine the behavior of waves in various media in terms of reflection, refraction, and diffraction of
e. Determine the location and nature of images formed by the reflection or refraction of light.