| Date | May 2012 | Marks available | 2 | Reference code | 12M.3.SL.TZ2.17 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | State | Question number | 17 | Adapted from | N/A |
Question
This question is about the nature of electromagnetic waves.
Outline what is meant by an electromagnetic wave.
State two cases in which electrons may produce electromagnetic waves.
Markscheme
oscillating/vibrating electric and magnetic fields;
at right angles to each other;
at right angles to the direction of propagation/energy transfer of the wave/ velocity/transverse;
can travel through vacuum;
Award [2] for a clearly drawn, correctly labelled diagram i.e. E and B fields at right angles to each other and at right angles to the direction of propagation.
electrons that oscillate/accelerate/move on curved paths;
electrons making transitions between energy levels;
Accept two specific instances of electrons being accelerated/decelerated e.g. electrons hitting metal target or electrons moving in magnetic fields.
Examiners report
