Doppler Effect Practice 2
10 problems · instant feedback · full explanations
Motion squeezes wavefronts ahead of the source (higher frequency) and stretches them behind (lower). Only the relative motion along the line of sight matters.
Q1.
A siren approaches you at constant speed. What happens to the observed frequency?
Multiple choice · Easy
Q2.
An ambulance siren at 700 Hz approaches at 30 m/s. What frequency is heard? (Use v = 343 m/s.)
Numerical answer (Hz) · Medium
Q3.
The same 700 Hz siren now recedes at 30 m/s. What frequency is heard? (Use v = 343 m/s.)
Numerical answer (Hz) · Medium
Q4.
Light from distant galaxies is shifted to longer wavelengths. This is called:
Multiple choice · Easy
Q5.
What determines the Doppler shift observed from a moving source?
Multiple choice · Medium
Q6.
A 1000 Hz horn on a car approaching at 40 m/s is heard by an observer moving toward it at 20 m/s. Observed frequency? (v = 343 m/s.)
Numerical answer (Hz) · Hard
Q7.
The Doppler effect changes the observed frequency, not the frequency emitted by the source.
True / False · Easy
Q8.
The standard Doppler formula works fine for supersonic sources.
True / False · Medium
Q9.
Police radar guns measure speed using:
Multiple choice · Medium
Q10.
At what Mach number does a sonic boom first form?
Multiple choice · Hard