Answer :
Compared to the sound waves detected by the driver of the truck, the sound waves detected by the observer have a greater "(2) frequency" and will be more high pitched.
Answer: The correct option is (2).
Explanation:
Doppler effect is the phenomenon in which the frequency of the wave increase or decrease when there is relative motion between the source and the listener. There is an apparent change in the frequency.
When the source and the listener are approaching each other then there will be increase in the frequency.
When the source and the listener are moving away form each other then there will be decrease in the frequency.
In the given problem, Sound waves are produced by the horn of a truck
that is approaching a stationary observer. The sound waves detected by the observer have greater frequency.
Therefore, the correct option is (2).
