1) When a 9.0 cm long pencil is arranged perpendicular to a convex mirror's optical axis at a distance of 22 cm from the mirror, its image is 7.2 cm tall.
(a) What is the mirror's focal length (include sign if negative)?
(b) How tall is the pencil's image if the pencil is moved to a distance of 50 cm from the mirror (include sign if negative)?
2) A thin glass rod is submerged in oil. What is the critical angle for light traveling inside the rod?