All Flashcards
What is the Doppler effect?
The change in frequency of a wave due to the relative motion between the source and the observer.
Define 'rest frequency'.
The frequency of a wave when the source and observer are not moving relative to each other.
Define 'observed frequency'.
The frequency detected by the observer, which differs from the rest frequency when there's relative motion.
What is 'redshift' in astronomy?
A decrease in the frequency of light from a receding object, indicating it's moving away from the observer.
What is 'blueshift' in astronomy?
An increase in the frequency of light from an approaching object, indicating it's moving towards the observer.
What is the effect of an approaching source on the observed frequency?
The observed frequency is higher than the rest frequency (positive Doppler shift).
What is the effect of a receding source on the observed frequency?
The observed frequency is lower than the rest frequency (negative Doppler shift).
What effect does increasing the relative velocity between the source and observer have?
A larger difference between the observed and rest frequencies.
What is the effect if the source and observer move at the same velocity?
There is no Doppler shift, and the observed frequency equals the rest frequency.
What is the effect of a positive Doppler shift?
The source is approaching the observer.
What is the effect of a negative Doppler shift?
The source is receding from the observer.
What is the effect of a source approaching an observer?
The observed frequency is higher than the rest frequency (positive Doppler shift).
What is the effect of a source receding from an observer?
The observed frequency is lower than the rest frequency (negative Doppler shift).
What happens to the Doppler shift as the source's speed increases?
The magnitude of the Doppler shift (the difference between observed and rest frequencies) also increases.
What happens when there is no relative motion between source and observer?
There is no Doppler shift, and the observed frequency equals the rest frequency.
What is the effect of analyzing the Doppler shift of reflected radio waves?
It allows radar guns to measure vehicle speeds.