A student investigating surface area to volume ratio and diffusion prepared a cuboid, S1, from agar coloured blue with a pH indicator. The dimensions of S1 are given in the diagram. The student then prepared a second agar cuboid, S2. For S2, each dimension — the length, the width and the height — was half the corresponding dimension of S1. Each cuboid was put into a test-tube and then covered with acid. The student measured how long each cuboid took to turn completely from one colour to another. Every variable except the size of the cuboids was kept the same. Which row gives the surface area to volume ratio of S1 and the time taken for S1 to change colour completely in acid compared with the time taken for S2 to change colour completely?
- Asurface area to volume ratio of S1: 0.72 : 1; S1 takes less time than S2
- Bsurface area to volume ratio of S1: 0.72 : 1; S1 takes more time than S2
- Csurface area to volume ratio of S1: 1.4 : 1; S1 takes less time than S2
- Dsurface area to volume ratio of S1: 1.4 : 1; S1 takes more time than S2