Question 18N.2.SL.TZ0.4c.ii
| Date | November 2018 | Marks available | [Maximum mark: 2] | Reference code | 18N.2.SL.TZ0.4c.ii |
| Level | SL | Paper | 2 | Time zone | TZ0 |
| Command term | Outline | Question number | c.ii | Adapted from | N/A |
A pipe is open at both ends. A first-harmonic standing wave is set up in the pipe. The diagram shows the variation of displacement of air molecules in the pipe with distance along the pipe at time t = 0. The frequency of the first harmonic is f.
A transmitter of electromagnetic waves is next to a long straight vertical wall that acts as a plane mirror to the waves. An observer on a boat detects the waves both directly and as an image from the other side of the wall. The diagram shows one ray from the transmitter reflected at the wall and the position of the image.
Outline why the observer detects a series of increases and decreases in the intensity of the received signal as the boat moves along the line XY.
[2]
interference pattern is observed
OR
interference/superposition mentioned ✔
maximum when two waves occur in phase/path difference is nλ
OR
minimum when two waves occur 180° out of phase/path difference is (n + ½)λ ✔
