question_answer

Sound of frequency \[1000\text{ }Hz\] from a stationary source is reflected from an object approaching the source at\[30\text{ }m{{s}^{-1}}\], back to a stationary observer located at the source. The speed of sound in air is \[330m{{s}^{-1}}\]. The frequency of the sound heard by the observer is

A) \[1200\text{ }Hz\]          

B) \[1000\text{ }Hz\]

C) \[1090\text{ }Hz\]          

D) 1100 Hz