DP Physics (last assessment 2024)
Question 18M.2.HL.TZ1.3a.ii
| Date | May 2018 | Marks available | [Maximum mark: 1] | Reference code | 18M.2.HL.TZ1.3a.ii |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Outline | Question number | a.ii | Adapted from | N/A |
a.ii.
[Maximum mark: 1]
18M.2.HL.TZ1.3a.ii
A beam of coherent monochromatic light from a distant galaxy is used in an optics experiment on Earth.
The beam is incident normally on a double slit. The distance between the slits is 0.300 mm. A screen is at a distance D from the slits. The diffraction angle θ is labelled.
(a.ii)
Outline why the beam has to be coherent in order for the fringes to be visible.
[1]
Markscheme
light waves (from slits) must have constant phase difference / no phase difference / be in phase
OWTTE
[1 mark]
