The Doppler Effect

Question 1

Definition of the Doppler Effect

Answer 1

The change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.

Question 2

Doppler Shift Formula for Sound

Answer 2

f ′ = f (​v+vo / v−vs)
where 𝑓′ is the observed frequency,
𝑓 is the source frequency,
𝑣 is the speed of sound,
𝑣o is the observer’s velocity, and
​𝑣s is the source’s velocity.

Question 3

Source Moving Towards Observer

Answer 3

The observed frequency increases as the source approaches the observer.

Question 4

Source Moving Away from Observer

Answer 4

The observed frequency decreases as the source moves away from the observer.

Question 5

Observer Moving Towards Source

Answer 5

The observed frequency increases as the observer moves towards the source.

Question 6

Observer Moving Away from Source

Answer 6

The observed frequency decreases as the observer moves away from the source.

Question 7

Doppler Effect in Light

Answer 7

For light waves, an increase in frequency is called a blueshift, and a decrease is called a redshift.

Question 8

Sonic Boom

Answer 8

A shock wave produced when an object travels through a medium faster than the speed of sound, leading to a sudden change in pressure.