Physics (AS & A Level) · Oct / Nov 2016 · Paper 11 · Question 26

The warning signal on an ambulance has a frequency of 600 Hz. The speed of sound is 330 m s⁻¹. The ambulance is travelling with a constant velocity of 25 m s⁻¹ towards an observer. [diagram: initial position of ambulance, observer, final position of ambulance] Which overall change in observed frequency takes place between the times at which the ambulance is a long way behind the observer and when it is a long way in front of the observer?

1. A49 Hz
2. B84 Hz
3. C91 Hz
4. D98 Hz

As printed in the paper