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?
✓ Correct Answer
The correct answer is C: The observed frequency will rise, then remain steady then fall to a lower frequency than F₀.
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
Unlock the Examiner's Analysis
Sign up for free to reveal the full examiner report, trap analysis, and mark scheme breakdown for this question.
Sign Up Free to Unlock →Join thousands of Cambridge students already using Oracle Prep