| Date | May 2019 | Marks available | 2 | Reference code | 19M.3.SL.TZ1.8 |
| Level | Standard level | Paper | Paper 3 | Time zone | 1 |
| Command term | Draw | Question number | 8 | Adapted from | N/A |
Question
Plane wavefronts in air are incident on the curved side of a transparent semi-circular block of refractive index 2.0.
Part of wavefront XY outside the block is shown.
Draw, on the diagram, the wavefront inside the block.
Markscheme
smooth curve of correct curvature continuous at the boundary as shown ✔
wavelength must be half the one in air; judge by eye ✔
Examiners report
Wavefronts. This straightforward application of this core topic on wave characteristics was only done well by the best candidates. Many candidates showed significant problems in demonstrating a basic understanding of manipulating wavefronts through changing mediums.
