Question 19M.2.HL.TZ1.3c
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.HL.TZ1.3c |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Outline | Question number | c | 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.
Outline one reason why the maxima observed at W, X and Y will have different intensities from each other.
[1]
intensity is modulated by a single slit diffraction envelope OR
intensity varies with distance OR points are different distances from the slits ✔
This is one of many questions on this paper where candidates wrote vague answers that did not clearly connect to physics concepts or include key information. There were many overly simplistic answers like “they are farther away” without specifying what they are farther away from. Candidates should be reminded that their responses should go beyond the obvious and include some evidence of deeper understanding.
