the figure shows a sound wave as a function of time when the source is stationary with respect to the…

the figure shows a sound wave as a function of time when the source is stationary with respect to the observer. which shows the perceived sound wave heard by a stationary observer when the source moves toward the observer?
Answer
Explanation:
Step1: Recall Doppler - effect principle
When a sound - source moves towards a stationary observer, the frequency of the sound wave perceived by the observer increases.
Step2: Analyze wave characteristics
An increase in frequency means more wave - cycles in the same time interval. The original wave has a certain number of cycles in 1 second. When the source moves towards the observer, the number of cycles in 1 second should increase.
Answer:
The wave with more cycles in 1 - second (the bottom - right wave in the options if the description is correct)