Question

2. A moving police car plays a sound with constant frequency f0. The police car moves

from the stationary observer on the right, R, towards the stationary observer on the

left, L. How does the frequency, fL , observed by the observer on the left compare to

the frequency, fR , observed on the right?

(a) fL > fR

(b) fL < fR

(c) fL = fR

3. A speaker at rest plays a sound with constant frequency f0 near a straight train track.

Train A moves away from the speaker, and train B moves toward the speaker. How

does the frequency, fA , observed by a rider on train A compare to the frequency, fB,

observed by a rider on train B?

(a) fL > fR

(b) fL < fR

(c) fL = fR

8. A source S emits sound of frequency f. If the source moves away from the receiver

O, the frequency perceived by the receiver

(a) is always lower than f

(b) is always higher than f

(c) can be lower if the intensity is low

(d) can be higher depending on the quality of the sound emitted by the source.

9. In a brief paragraph, give three examples of the practical applications of the Doppler
effect.

10. A certain note of the piano has a frequency of f = 440Hz. What is the frequency of

the note an octave lower?

11. A certain note of the piano has a frequency of f=600Hz. What is the frequency of the

note a fifth higher?

Answer 1