Question 19M.2.HL.TZ1.d
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.HL.TZ1.d |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Sketch | Question number | d | Adapted from | N/A |
A beam of microwaves is incident normally on a pair of identical narrow slits S1 and S2.
When a microwave receiver is initially placed at W which is equidistant from the slits, a maximum in intensity is observed. The receiver is then moved towards Z along a line parallel to the slits. Intensity maxima are observed at X and Y with one minimum between them. W, X and Y are consecutive maxima.
The microwaves emitted by the transmitter are horizontally polarized. The microwave receiver contains a polarizing filter. When the receiver is at position W it detects a maximum intensity.
The receiver is then rotated through 180° about the horizontal dotted line passing through the microwave transmitter. Sketch a graph on the axes provided to show the variation of received intensity with rotation angle.
[2]
cos2 variation shown ✔
with zero at 90° (by eye) ✔
Award [1 max] for an inverted curve with maximum at 90°.
This question was generally well answered, with many candidates at least recognizing that the intensity would decrease to zero at 90 degrees. Many struggled with the exact shape of the graph, though, and some drew a graph that extended below zero showing a lack of understanding of what was being graphed.
