| Date | November 2014 | Marks available | 1 | Reference code | 14N.1.HL.TZ0.16 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Question number | 16 | Adapted from | N/A |
Question
Radiation is incident on a single rectangular slit. The diffracted beam that emerges from the slit is incident on a screen. The slit width is then doubled and the wavelength of the radiation is also doubled. The intensity of the radiation remains the same.
Which of the following correctly describes the angular width of the central maximum of the diffracted beam and the total number of photons incident every second on the screen?
Markscheme
C
Examiners report
A was a popular choice, indicating that some candidates were unsure of the relationship between the number of photons per second in a light wave, the intensity of the wave and its frequency.
