An object is located 8 cm away from a convex lens. The image is 24 cm away from the lens on the other side. What is the focal length of the lens?
A. 4 cm
B. 6 cm
C. 16 cm
D. 32 cm

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)