A-LevelPhysicsWaves9702/12 · Feb/Mar 2018 · Q241 Mark
A vehicle carries a microwave transmitter that emits microwaves of a constant frequency. A stationary observer has a microwave receiver. The vehicle moves directly towards the observer at constant speed. The observer detects microwaves of frequency F₀. The vehicle then accelerates, still moving towards the observer, travels at higher steady speed for a time and then decelerates until it stops. What is the variation in the frequency of the microwaves that are detected by the observer?
AThe observed frequency will fall, then remain steady then return to the frequency F₀.
BThe observed frequency will fall, then remain steady then rise to a higher frequency than F₀.
CThe observed frequency will rise, then remain steady then fall to a lower frequency than F₀.
DThe observed frequency will rise, then remain steady then return to the frequency F₀.
✓ Correct answer
C: The observed frequency will rise, then remain steady then fall to a lower frequency than F₀.
Practise more questions on this topic
Oracle Prep sorts past-paper questions by topic, so you can drill Waves and see which topics are most likely to come up next.
Sign up free →